





















                                 GGNNUUPPLLOOTT
                     AAnn IInntteerraaccttiivvee PPlloottttiinngg PPrrooggrraamm



                      _T_h_o_m_a_s _W_i_l_l_i_a_m_s _& _C_o_l_i_n _K_e_l_l_e_y
               _V_e_r_s_i_o_n _4_._1 _o_r_g_a_n_i_z_e_d _b_y_: _H_a_n_s_-_B_e_r_n_h_a_r_d _B_r_o_e_k_e_r
                   _M_a_j_o_r _c_o_n_t_r_i_b_u_t_o_r_s _(_a_l_p_h_a_b_e_t_i_c _o_r_d_e_r_)_:
                           _H_a_n_s_-_B_e_r_n_h_a_r_d _B_r_o_e_k_e_r
                               _J_o_h_n _C_a_m_p_b_e_l_l
                             _R_o_b_e_r_t _C_u_n_n_i_n_g_h_a_m
                               _D_a_v_i_d _D_e_n_h_o_l_m
                               _G_e_r_s_h_o_n _E_l_b_e_r
                               _R_o_g_e_r _F_e_a_r_i_c_k
                              _C_a_r_s_t_e_n _G_r_a_m_m_e_s
                                 _L_u_c_a_s _H_a_r_t
                                _L_a_r_s _H_e_c_k_i_n_g
                               _T_h_o_m_a_s _K_o_e_n_i_g
                                 _D_a_v_i_d _K_o_t_z
                                _E_d _K_u_b_a_i_t_i_s
                                _R_u_s_s_e_l_l _L_a_n_g
                             _A_l_e_x_a_n_d_e_r _L_e_h_m_a_n_n
                               _A_l_e_x_a_n_d_e_r _M_a_i
                               _E_t_h_a_n _M_e_r_r_i_t_t
                                _P_e_t_r _M_i_k_u_l_i_k
                               _C_a_r_s_t_e_n _S_t_e_g_e_r
                                 _T_o_m _T_k_a_c_i_k
                             _J_o_s _V_a_n _d_e_r _W_o_u_d_e
                                  _A_l_e_x _W_o_o
                             _J_a_m_e_s _R_. _V_a_n _Z_a_n_d_t
                              _J_o_h_a_n_n_e_s _Z_e_l_l_n_e_r
     _C_o_p_y_r_i_g_h_t _(_C_) _1_9_8_6 _- _1_9_9_3_, _1_9_9_8_, _2_0_0_4   _T_h_o_m_a_s _W_i_l_l_i_a_m_s_, _C_o_l_i_n _K_e_l_l_e_y
        Mailing list for comments: gnuplot-info@lists.sourceforge.net
      Mailing list for bug reports: gnuplot-bugs@lists.sourceforge.net
                              19 April 2013



















                                    -2-








                This manual was prepared by Dick Crawford.
                             3 December 1998





























































   11..  GGnnuupplloott





   22..  CCooppyyrriigghhtt


       Copyright (C) 1986 - 1993, 1998, 2004, 2007  Thomas Williams,
   Colin Kelley

   Permission to use, copy, and distribute this software and its docu-
   mentation for any purpose with or without fee is hereby granted,
   provided that the above copyright notice appear in all copies and
   that both that copyright notice and this permission notice appear in
   supporting documentation.

   Permission to modify the software is granted, but not the right to
   distribute the complete modified source code.  Modifications are to
   be distributed as patches to the released version.  Permission to
   distribute binaries produced by compiling modified sources is
   granted, provided you
     1. distribute the corresponding source modifications from the
      released version in the form of a patch file along with the bina-
   ries,
     2. add special version identification to distinguish your version
      in addition to the base release version number,
     3. provide your name and address as the primary contact for the
      support of your modified version, and
     4. retain our contact information in regard to use of the base
      software.
   Permission to distribute the released version of the source code
   along with corresponding source modifications in the form of a patch
   file is granted with same provisions 2 through 4 for binary distri-
   butions.

   This software is provided "as is" without express or implied war-
   ranty to the extent permitted by applicable law.


         AUTHORS

         Original Software:










   GNUPLOT 4.1                                                        2


            Thomas Williams,  Colin Kelley.

         Gnuplot 2.0 additions:
            Russell Lang, Dave Kotz, John Campbell.

         Gnuplot 3.0 additions:
            Gershon Elber and many others.

         Gnuplot 4.0 additions:
            See list of contributors at head of this document.



   33..  IInnttrroodduuccttiioonn


   GGnnuupplloott is a portable command-line driven graphing utility for
   Linux, OS/2, MS Windows, OSX, VMS, and many other platforms. The
   source code is copyrighted but freely distributed (i.e., you don't
   have to pay for it). It was originally created to allow scientists
   and students to visualize mathematical functions and data interac-
   tively, but has grown to support many non-interactive uses such as
   web scripting. It is also used as a plotting engine by third-party
   applications like Octave. Gnuplot has been supported and under
   active development since 1986.

   Gnuplot supports many types of plots in either 2D and 3D. It can
   draw using lines, points, boxes, contours, vector fields, surfaces,
   and various associated text. It also supports various specialized
   plot types.

   Gnuplot supports many different types of output: interactive screen
   terminals (with mouse and hotkey input), direct output to pen plot-
   ters or modern printers, and output to many file formats (eps, emf,
   fig, jpeg, LaTeX, pdf, png, postscript, ...). Gnuplot is easily
   extensible to include new output modes.  Recent additions include
   interactive terminals based on wxWidgets (usable on multiple plat-
   forms), and Qt.  Mouseable plots embedded in web pages can be gener-
   ated using the svg or HTML5 canvas terminal drivers.

   The command language of ggnnuupplloott is case sensitive, i.e. commands and
   function names written in lowercase are not the same as those writ-
   ten in capitals. All command names may be abbreviated as long as the
   abbreviation is not ambiguous. Any number of commands may appear on
   a line, separated by semicolons (;). Strings may be set off by
   either single or double quotes, although there are some subtle dif-
   ferences.  See ssyynnttaaxx and qquuootteess for more details. Examples:

         load "filename"
         cd 'dir'

   Commands may extend over several input lines by ending each line but
   the last with a backslash (\).  The backslash must be the _last_










   GNUPLOT 4.1                                                        3


   character on each line.  The effect is as if the backslash and new-
   line were not there.  That is, no white space is implied, nor is a
   comment terminated.  Therefore, commenting out a continued line com-
   ments out the entire command (see ccoommmmeennttss).  But note that if an
   error occurs somewhere on a multi-line command, the parser may not
   be able to locate precisely where the error is and in that case will
   not necessarily point to the correct line.

   In this document, curly braces ({}) denote optional arguments and a
   vertical bar (|) separates mutually exclusive choices.  GGnnuupplloott key-
   words or hheellpp topics are indicated by backquotes or bboollddffaaccee (where
   available).  Angle brackets (<>) are used to mark replaceable
   tokens.  In many cases, a default value of the token will be taken
   for optional arguments if the token is omitted, but these cases are
   not always denoted with braces around the angle brackets.

   For built-in help on any topic, type hheellpp followed by the name of
   the topic or hheellpp ?? to get a menu of available topics.

   The new ggnnuupplloott user should begin by reading about pplloottttiinngg (if in
   an interactive session, type hheellpp pplloottttiinngg).

   See the simple.dem demo, also available together with other demos on
   the web page
             http://www.gnuplot.info/demo/
   GGnnuupplloott can be started from a command line or from an icon according
   to the desktop environment. Running it from command line can take
   the syntax
         gnuplot {OPTIONS} file1 file2 ...
   where file1, file2, etc. are input file as in the llooaadd command.  On
   X11-based systems, you can use
         gnuplot {X11OPTIONS} {OPTIONS} file1 file2 ...
   see your X11 documentation and xx1111 in this document.

   Options interpreted by gnuplot may come anywhere on the line.  Files
   are executed in the order specified, as are commands supplied by the
   -e option, for example
         gnuplot   file1.in   -e "reset"   file2.in

   The special filename "-" is used to force reading from stdin.  GGnnuu--
   pplloott exits after the last file is processed.  If no load files are
   named, GGnnuupplloott takes interactive input from stdin.  See help
   bbaattcchh//iinntteerraaccttiivvee for more details.  The options specific to gnuplot
   can be listed by typing
         gnuplot --help
   See ccoommmmaanndd lliinnee ooppttiioonnss for more details.

   In sessions with an interactive plot window you can hit 'h' anywhere
   on the plot for help about hhoottkkeeyyss and mmoouussiinngg features.  Section
   sseeeekkiinngg--aassssiissttaannccee will help you to find further information, help
   and FAQ.












   GNUPLOT 4.1                                                        4


   44..  SSeeeekkiinngg--aassssiissttaannccee


   The canonical gnuplot web page can be found at
             http://www.gnuplot.info

   Before seeking help, please check file FAQ.pdf or the above website
   for
             FAQ (Frequently Asked Questions) list.

   If you need help as a gnuplot user, please use the newsgroup
             comp.graphics.apps.gnuplot
   We prefer that you read the messages through the newsgroup rather
   than subscribing to the mailing list which is also available and
   carries the same set of messages. Instructions for subscribing to
   gnuplot mailing lists may be found via the gnuplot development web-
   site on SourceForge
             http://sourceforge.net/projects/gnuplot

   The address for mailing to list members is:
             gnuplot-info@lists.sourceforge.net

   Bug reports and code contributions should be uploaded to the track-
   ers at
             http://sourceforge.net/projects/gnuplot/support
   Please check previous bug reports if the bug you want to report has
   not been already fixed in a newer version of gnuplot.

   A mailing list for those interested in development version of gnu-
   plot is:
             gnuplot-beta@lists.sourceforge.net

   When posting a question, please include full details of the gnuplot
   version, the terminal type, and the operating system you are using.
   A _small_ script demonstrating the problem may be useful.  Function
   plots are preferable to datafile plots.




   55..  NNeeww ffeeaattuurreess


   This section lists major additions since version 4.4.  For a more
   exhaustive list, see the NEWS file.


















   GNUPLOT 4.1                                                        5


        55..11..  NNeeww ssyynnttaaxx


        This version of gnuplot introduces command iteration and block-
        structured if/else/while/do constructs.  See iiff, wwhhiillee, and ddoo.
        Simple iteration is possible inside pplloott or sseett commands.  See
        iitteerraattiioonn.  General iteration spanning multiple commands is
        possible using a block construct as shown below.  For a related
        new feature, see the ssuummmmaattiioonn expression type.  Here is an
        example using several of these new syntax features:
              set multiplot layout 2,2
              fourier(k, x) = sin(3./2*k)/k * 2./3*cos(k*x)
              do for [power = 0:3] {
                  TERMS = 10**power
                  set title sprintf("%g term Fourier series",TERMS)
                  plot 0.5 + sum [k=1:TERMS] fourier(k,x) notitle
              }
              unset multiplot

        It is now possible to select a column of data from a data file
        by matching a label in the first row of the file. See ccoolluummnn--
        hheeaadd.  For example
              plot for [crop in "Oats Peas Beans"] 'data' using
        "Year":crop




        55..22..  LLooccaall ccuussttoommiizzaattiioonn ooff lliinneettyyppeess


        You can now customize properties (color, linewidth, point type)
        of the default sequence of linetypes used in plotting. See sseett
        lliinneettyyppee.  This is normally done in an initialization file,
        either the system-wide file ggnnuupplloottrrcc or a private file ~~//..ggnnuu--
        pplloott. See iinniittiiaalliizzaattiioonn.

        Most terminals now allow you to set an explicit background
        color for the plot.  The special linetype bbggnndd can be used to
        draw in this color. See bbggnndd.




        55..33..  NNeeww pplloott ssttyylleess


        See documentation for plot styles bbooxxpplloott, cciirrcclleess, eelllliippsseess,
        and ffiillllsstteeppss.














   GNUPLOT 4.1                                                        6


        55..44..  RReevviisseedd ppoollaarr aaxxeess


        Polar plot mode has been reworked to support additional plot
        styles.  The polar axes can now be drawn and labeled indepen-
        dent of the x and y axes. See sseett ppoollaarr and sseett rrrraannggee.




        55..55..  NNeeww ssmmooootthhiinngg aallggoorriitthhmmss


        New smoothing algorithms have been added for both 2- and
        3-dimensional plots.  ssmmooootthh kkddeennssiittyy and ssmmooootthh ccuummuullaattiivvee can
        be used with pplloott to draw smooth histograms and cumulative dis-
        tribution functions.  Several new smoothing kernels have been
        added to ddggrriidd33dd for use with sspplloott.  See ssmmooootthh ddggrriidd33dd.




        55..66..  NNeeww ttiimmee//ddaattee hhaannddlliinngg


        Gnuplot now tracks time to millisecond precision. Time formats
        have been modified to match this. The new built-in function
        time() returns the current time of day according to the system
        clock.  Example: print the current time to msec precision
             print strftime("%H:%M:%.3S %d-%b-%Y",time(0.0))
             18:15:04.253 16-Apr-2011



        55..77..  SSttaattiissttiiccaall ssuummmmaarryy ooff ddaattaa


        The new ssttaattss command reads data from a file using the same
        syntax as the pplloott or sspplloott commands. Rather than drawing a
        graph, it prints out a statistical summary of the data con-
        tained in the column[s] requested.  The resulting statistics
        min, max, mean, standard deviation, correlation, etc. are also
        stored in named variables that can be used to compose or modify
        subsequent plotting commands.  See ssttaattss.




        55..88..  NNeeww oorr rreevviisseedd tteerrmmiinnaall ddrriivveerrss


        The qqtt driver implements an interactive terminal on top of the
        Qt graphics layer.  It can function either as a window in a










   GNUPLOT 4.1                                                        7


        full-featured desktop enviroment or as a full-screen applica-
        tion on a Qt-based embedded device.  The qqtt terminal is new and
        may still have some rough edges.

        Two terminal types support web-based interactive display. The
        HTML5 ccaannvvaass terminal was introduced in version 4.4. The ssvvgg
        terminal has been extensively revised to include support for
        mousing and better incorporation of svg plots from gnuplot into
        larger svg/xml documents.

        The ccaannvvaass terminal driver produces javascript output that
        draws onto the HTML canvas element of a web page.  It can pro-
        duce either a complete web page containing a single plot, or a
        script that can be embedded as part of an externally generated
        HTML document that perhaps contains multiple plots.  The embed-
        ded plots support browser-side mousing, including zoom/unzoom.

        The lluuaa terminal driver creates data intended to be further
        processed by a script in the lua programming language.  At this
        point only one such lua script, gnuplot-tikz.lua, is available.
        It produces a TeX document suitable for use with the latex TikZ
        package.  Other lua scripts could be written to process the
        gnuplot output for use with other TeX packages, or with other
        non-TeX tools.

        sseett tteerrmm ttiikkzz is shorthand for sseett tteerrmm lluuaa ttiikkzz.  As decribed
        above, it uses the generic lua terminal and an external lua
        script to produce a latex document.

        The ccoonntteexxtt terminal driver creates output to be further pro-
        cessed by the ConTeXt TeX macro package. To process its output,
        you additionally require the gnuplot module for ConTeXt avail-
        able at
                  http://ctan.org/pkg/context-gnuplot

        The eeppssccaaiirroo terminal uses the cairo and pango libraries to
        create encapsulated postscript (eps) ouput. It is an alterna-
        tive to the ppoossttssccrriipptt terminal driver for those who would like
        to have their eps files look equal to e.g. screen output by the
        wwxxtt terminal.

        The ccaaiirroollaatteexx terminal uses the cairo backend of the ppddffccaaiirroo
        or eeppssccaaiirroo terminal to produce graphs for inclusion in LaTeX
        documents. It creates pdf or eps graphics but transfers texts
        to LaTeX in the same way as the eeppssllaatteexx terminal.

        The wwiinnddoowwss terminal driver has been revised to suport trans-
        parency, antialiasing, buffered output, multiple graph windows
        and copying to clipboard and saving of graphs as emf files. It
        has many new options and a revised user interface. Additionaly,
        the code of the text console has been largely rewritten to sup-
        port wrapping of long lines. Help is now provided via HTML.











   GNUPLOT 4.1                                                        8


   66..  BBaacckkwwaarrddss ccoommppaattiibbiilliittyy


   Gnuplot version 4.0 deprecated certain syntax used in earlier ver-
   sions, but continued to recognize it.  This is now under the control
   of a configuration option, and can be enabled as follows:

         ./configure --enable-backwards-compatibility

   Notice: Deprecated syntax items may be removed entirely in some
   future version of gnuplot.

   One major difference is the introduction of keywords to disambiguate
   complex commands, particularly commands containing string variables.
   A notable issue was the use of bare numbers to specify offsets, line
   and point types.  Illustrative examples:

   Deprecated:
         set title "Old" 0,-1
         set data linespoints
         plot 1 2 4               # horizontal line at y=1
   New:
         TITLE = "New"
         set title TITLE offset char 0, char -1
         set style data linespoints
         plot 1 linetype 2 pointtype 4




   77..  BBaattcchh//IInntteerraaccttiivvee OOppeerraattiioonn


   GGnnuupplloott may be executed in either batch or interactive modes, and
   the two may even be mixed together on many systems.

   Any command-line arguments are assumed to be either program options
   (first character is -) or names of files containing ggnnuupplloott com-
   mands. The option -e "command" may be used to force execution of a
   gnuplot command. Each file or command string will be executed in the
   order specified.  The special filename "-" is indicates that com-
   mands are to be read from stdin.  GGnnuupplloott exits after the last file
   is processed.  If no load files and no command strings are speci-
   fied, ggnnuupplloott accepts interactive input from stdin.

   Both the eexxiitt and qquuiitt commands terminate the current command file
   and llooaadd the next one, until all have been processed.

   Examples:

   To launch an interactive session:
         gnuplot











   GNUPLOT 4.1                                                        9


   To launch a batch session using two command files "input1" and
   "input2":
         gnuplot input1 input2

   To launch an interactive session after an initialization file
   "header" and followed by another command file "trailer":
         gnuplot header - trailer

   To give ggnnuupplloott commands directly in the command line, using the
   "-persist" option so that the plot remains on the screen afterwards:
         gnuplot -persist -e "set title 'Sine curve'; plot sin(x)"

   To set user-defined variables a and s prior to executing commands
   from a file:
         gnuplot -e "a=2; s='file.png'" input.gpl




   88..  CCaannvvaass ssiizzee



   In earlier versions of gnuplot, some terminal types used the values
   from sseett ssiizzee to control also the size of the output canvas; others
   did not.  The use of 'set size' for this purpose was deprecated in
   version 4.2.  Since version 4.4 almost all terminals now behave as
   follows:

   sseett tteerrmm <<tteerrmmiinnaall__ttyyppee>> ssiizzee <<XXXX>>,, <<YYYY>> controls the size of the
   output file, or "canvas". Please see individual terminal documenta-
   tion for allowed values of the size parameters.  By default, the
   plot will fill this canvas.

   sseett ssiizzee <<XXXX>>,, <<YYYY>> scales the plot itself relative to the size of
   the canvas.  Scale values less than 1 will cause the plot to not
   fill the entire canvas.  Scale values larger than 1 will cause only
   a portion of the plot to fit on the canvas.  Please be aware that
   setting scale values larger than 1 may cause problems on some termi-
   nal types.

   The major exception to this convention is the PostScript driver,
   which by default continues to act as it has in earlier versions. Be
   warned that the next version of gnuplot may change the default be-
   haviour of the PostScript driver as well.

   Example:

         set size 0.5, 0.5
         set term png size 600, 400
         set output "figure.png"
         plot "data" with lines











   GNUPLOT 4.1                                                       10


   These commands will produce an output file "figure.png" that is 600
   pixels wide and 400 pixels tall. The plot will fill the lower left
   quarter of this canvas.  This is consistent with the way multiplot
   mode has always worked.




   99..  CCoommmmaanndd--lliinnee--eeddiittiinngg


   Command-line editing and command history are supported using either
   an external gnu readline library, an external BSD libedit library,
   or a built-in equivalent.  This choice is a configuration option at
   the time gnuplot is built.

   The editing commands of the built-in version are given below. Please
   note that the action of the DEL key is system-dependent. The gnu
   readline and BSD libedit libraries have their own documentation.




      +-------------------------------------------------------------+
      |Character   Function                                         |
      +-------------------------------------------------------------+
      |            Line Editing                                     |
      |   ^B       move back a single character.                    |
      |   ^F       move forward a single character.                 |
      |   ^A       move to the beginning of the line.               |
      |   ^E       move to the end of the line.                     |
      |   ^H       delete the previous character.                   |
      |   DEL      delete the current character.                    |
      |   ^D       delete current character. EOF if line is empty.  |
      |   ^K       delete from current position to the end of line. |
      | ^L, ^R     redraw line in case it gets trashed.             |
      |   ^U       delete the entire line.                          |
      |   ^W       delete previous word.                            |
      +-------------------------------------------------------------+
      |            History                                          |
      |   ^P       move back through history.                       |
      |   ^N       move forward through history.                    |
      +-------------------------------------------------------------+






   1100..  CCoommmmeennttss













   GNUPLOT 4.1                                                       11


   Comments are supported as follows: a ## may appear in most places in
   a line and ggnnuupplloott will ignore the rest of the line.  It will not
   have this effect inside quotes, inside numbers (including complex
   numbers), inside command substitutions, etc.  In short, it works
   anywhere it makes sense to work.

   See also sseett ddaattaaffiillee ccoommmmeennttsscchhaarrss for specifying comment charac-
   ters in data files.  Note that if a comment line ends in '\' then
   the subsequent line is also treated as a comment.



   1111..  CCoooorrddiinnaatteess


   The commands sseett aarrrrooww, sseett kkeeyy, sseett llaabbeell and sseett oobbjjeecctt allow you
   to draw something at an arbitrary position on the graph.  This posi-
   tion is specified by the syntax:

         {<system>} <x>, {<system>} <y> {,{<system>} <z>}

   Each <system> can either be ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacc--
   tteerr.

   ffiirrsstt places the x, y, or z coordinate in the system defined by the
   left and bottom axes; sseeccoonndd places it in the system defined by the
   second axes (top and right); ggrraapphh specifies the area within the
   axes---0,0 is bottom left and 1,1 is top right (for splot, 0,0,0 is
   bottom left of plotting area; use negative z to get to the
   base---see sseett xxyyppllaannee); ssccrreeeenn specifies the screen area (the
   entire area---not just the portion selected by sseett ssiizzee), with 0,0
   at bottom left and 1,1 at top right; and cchhaarraacctteerr gives the posi-
   tion in character widths and heights from the bottom left of the
   screen area (screen 0,0), cchhaarraacctteerr coordinates depend on the chosen
   font size.

   If the coordinate system for x is not specified, ffiirrsstt is used.  If
   the system for y is not specified, the one used for x is adopted.

   In some cases, the given coordinate is not an absolute position but
   a relative value (e.g., the second position in sseett aarrrrooww ... rrttoo).
   In most cases, the given value serves as difference to the first
   position.  If the given coordinate resides in a logarithmic axis the
   value is interpreted as factor. For example,

         set logscale x
         set arrow 100,5 rto 10,2

   plots an arrow from position 100,5 to position 1000,7 since the x
   axis is logarithmic while the y axis is linear.

   If one (or more) axis is timeseries, the appropriate coordinate
   should be given as a quoted time string according to the ttiimmeeffmmtt










   GNUPLOT 4.1                                                       12


   format string.  See sseett xxddaattaa and sseett ttiimmeeffmmtt.  GGnnuupplloott will also
   accept an integer expression, which will be interpreted as seconds
   from 1 January 2000.



   1122..  DDaattaassttrriinnggss


   Data files may contain string data consisting of either an arbitrary
   string of printable characters containing no whitespace or an arbi-
   trary string of characters, possibly including whitespace, delimited
   by double quotes.  The following sample line from a datafile is
   interpreted to contain four columns, with a text field in column 3:

     1.000 2.000 "Third column is all of this text" 4.00

   Text fields can be positioned within a 2-D or 3-D plot using the
   commands:

     plot 'datafile' using 1:2:4 with labels
     splot 'datafile' using 1:2:3:4 with labels

   A column of text data can also be used to label the ticmarks along
   one or more of the plot axes. The example below plots a line through
   a series of points with (X,Y) coordinates taken from columns 3 and 4
   of the input datafile.  However, rather than generating regularly
   spaced tics along the x axis labeled numerically, gnuplot will posi-
   tion a tic mark along the x axis at the X coordinate of each point
   and label the tic mark with text taken from column 1 of the input
   datafile.

     set xtics
     plot 'datafile' using 3:4:xticlabels(1) with linespoints

   There is also an option that will interpret the first entry in a
   column of input data (i.e. the column heading) as a text field, and
   use it as the key title for data plotted from that column. The exam-
   ple given below will use the first entry in column 2 to generate a
   title in the key box, while processing the remainder of columns 2
   and 4 to draw the required line:

     plot 'datafile' using 1:(f($2)/$4) with lines title columnhead(2)

   Another example:

     plot for [i=2:6] 'datafile' using i title "Results for ".column-
   head(i)

   See sseett ssttyyllee llaabbeellss, uussiinngg xxttiiccllaabbeellss, pplloott ttiittllee, uussiinngg.













   GNUPLOT 4.1                                                       13


   1133..  EEnnhhaanncceedd tteexxtt mmooddee


   Many terminal types support an enhanced text mode in which addi-
   tional formatting information is embedded in the text string.  For
   example, "x^2" will write x-squared as we are used to seeing it,
   with a superscript 2.  This mode is normally selected when you set
   the terminal, e.g.  "set term png enhanced", but may also be toggled
   afterward using "set termoption enhanced", or by marking individual
   strings as in "set label 'x_2' noenhanced".




        +--------------------------------------------------------+
        |.lf 906  _C_o_n_tc_re_on_ltEexramb_cpo_clx_le.st_Ea_xb_p_l(_a)_n;_a_t_i_o_n        ..._n_n_n_r_r_r333_b_b_b_o_o_o_t_t_t_8_8_8_0_0_0>>>???_8_8_8_0_0_0...|_s_s_s_p_p_p|||_8_1_2_0_6_0_u_0_0._u_u3.._r33_v_r_r_p_v_v_t_p_p1_t_t.11_s.._p_s_s|_p_p_8||_0_8_8_u_0_0._u_u_n.._r_n_n3_r_r_b33_r_b_b_u_r_r_l_u_u_e_l_l1_e_e.113.._r3_v_e_r_s_l_e2_e_l_p_a_e>_s_a?_e_s_4._e_03._u_k3._e_k_l_e_e_s_p_e1._p3._r3_m_r_k_m3_k_r3_t_r1_t.2_n._r_n3_r_c3_r_c_o_r_w_o1_w.23._k3_e_k_e_e_p_e._p_m._k_m3_k_r3_s_r1_s.2_m._k_m3_k_b3_o_b_t_o._t3._r3_v_r_p_v_t_p0_t.0_t._a_t_1_a_0_1_3_0_2_3_u_2._u_l._f_l8_f28021
        |    & inserts space of specified length                 |
        | ~ _a.8-overprints '-' on 'a', raised by .8              |
        |         times the current fontsize                     |
        +--------------------------------------------------------+




   Braces can be used to place multiple-character text where a single
   character is expected (e.g., 2^{10}).  To change the font and/or
   size, use the full form: {/[fontname][=fontsize | *fontscale] text}.
   Thus {/Symbol=20 G} is a 20 pt GAMMA and {/*0.75 K} is a K at three-
   quarters of whatever fontsize is currently in effect.  (The '/'
   character MUST be the first character after the '{'.)

   The phantom box is useful for a@^b_c to align superscripts and sub-
   scripts but does not work well for overwriting an accent on a let-
   ter.  For the latter, it is much better to use an encoding  (e.g.
   iso_8859_1 or utf8) that contains a large variety of letters with
   accents or other diacritical marks.  See sseett eennccooddiinngg. Since the box
   is non-spacing, it is sensible to put the shorter of the subscript
   or superscript in the box (that is, after the @).

   Space equal in length to a string can be inserted using the '&'
   character.  Thus
           'abc&{def}ghi'
   would produce
           'abc   ghi'.

   The '~' character causes the next character or bracketed text to be
   overprinted by the following character or bracketed text.  The sec-
   ond text will be horizontally centered on the first.  Thus '~a/'
   will result in an 'a' with a slash through it.  You can also shift
   the second text vertically by preceding the second text with a num-
   ber, which will define the fraction of the current fontsize by which
   the text will be raised or lowered.  In this case the number and
   text must be enclosed in brackets because more than one character is










   GNUPLOT 4.1                                                       14


   necessary.  If the overprinted text begins with a number, put a
   space between the vertical offset and the text ('~{abc}{.5 000}');
   otherwise no space is needed ('~{abc}{.5---}').  You can change the
   font for one or both strings ('~a{.5 /*.2 o}'---an 'a' with a one-
   fifth-size 'o' on top---and the space between the number and the
   slash is necessary), but you can't change it after the beginning of
   the string.  Neither can you use any other special syntax within
   either string.  You can, of course, use control characters by escap-
   ing them (see below), such as '~a{\^}'

   You can access special symbols numerically by specifying \character-
   code (in octal), e.g., {/Symbol \245} is the symbol for infinity.
   This does not work for multibyte encodings like UTF-8, however.  In
   a UTF-8 environment, you should be able to enter multibyte sequences
   implicitly by typing or otherwise selecting the character you want.

   You can escape control characters using \, e.g.,  \\, \{, and so on.

   But be aware that strings in double-quotes are parsed differently
   than those enclosed in single-quotes.  The major difference is that
   backslashes may need to be doubled when in double-quoted strings.

   Examples (these are hard to describe in words---try them!):
         set xlabel 'Time (10^6 {/Symbol m}s)'
         set title '{/Symbol=18 \\362@_{/=9.6 0}^{/=12 x}} \\
                    {/Helvetica e^{-{/Symbol m}^2/2} d}{/Symbol m}'

   The file "ps_guide.ps" in the /docs/psdoc subdirectory of the gnu-
   plot source distribution contains more examples of the enhanced syn-
   tax.



   1144..  EEnnvviirroonnmmeenntt


   A number of shell environment variables are understood by ggnnuupplloott.
   None of these are required, but may be useful.

   If GNUTERM is defined, it is used as the name of the terminal type
   to be used.  This overrides any terminal type sensed by ggnnuupplloott on
   start-up, but is itself overridden by the .gnuplot (or equivalent)
   start-up file (see ssttaarrttuupp) and, of course, by later explicit
   changes.

   GNUHELP may be defined to be the pathname of the HELP file (gnu-
   plot.gih).

   On VMS, the logical name GNUPLOT$HELP should be defined as the name
   of the help library for ggnnuupplloott.  The ggnnuupplloott help can be put inside
   any system help library, allowing access to help from both within
   and outside ggnnuupplloott if desired.











   GNUPLOT 4.1                                                       15


   On Unix, HOME is used as the name of a directory to search for a
   .gnuplot file if none is found in the current directory.  On MS-DOS,
   Windows and OS/2, GNUPLOT is used.  On Windows, the NT-specific
   variable USERPROFILE is also tried. VMS, SYS$LOGIN: is used. Type
   hheellpp ssttaarrttuupp.

   On Unix, PAGER is used as an output filter for help messages.

   On Unix, SHELL is used for the sshheellll command.  On MS-DOS and OS/2,
   COMSPEC is used for the sshheellll command.

   FIT_SCRIPT may be used to specify a ggnnuupplloott command to be executed
   when a fit is interrupted---see ffiitt.  FIT_LOG specifies the default
   filename of the logfile maintained by fit.

   GNUPLOT_LIB may be used to define additional search directories for
   data and command files. The variable may contain a single directory
   name, or a list of directories separated by a platform-specific path
   separator, eg. ':' on Unix, or ';' on DOS/Windows/OS/2 platforms.
   The contents of GNUPLOT_LIB are appended to the llooaaddppaatthh variable,
   but not saved with the ssaavvee and ssaavvee sseett commands.

   Several gnuplot terminal drivers access TrueType fonts via the gd
   library.  For these drivers the font search path is controlled by
   the environmental variable GDFONTPATH.  Furthermore, a default font
   for these drivers may be set via the environmental variable GNU-
   PLOT_DEFAULT_GDFONT.

   The postscript terminal uses its own font search path. It is con-
   trolled by the environmental variable GNUPLOT_FONTPATH. The format
   is the same as for GNUPLOT_LIB. The contents of GNUPLOT_FONTPATH are
   appended to the ffoonnttppaatthh variable, but not saved with the ssaavvee and
   ssaavvee sseett commands.

   GNUPLOT_PS_DIR is used by the postscript driver to search for exter-
   nal prologue files. Depending on the build process, gnuplot contains
   either a built-in copy of those files or a default hardcoded path.
   You can use this variable have the postscript terminal use custom
   prologue files rather than the default files. See ppoossttssccrriipptt pprroo--
   lloogguuee.



   1155..  EExxpprreessssiioonnss


   In general, any mathematical expression accepted by C, FORTRAN, Pas-
   cal, or BASIC is valid.  The precedence of these operators is deter-
   mined by the specifications of the C programming language.  White
   space (spaces and tabs) is ignored inside expressions.

   Complex constants are expressed as {<real>,<imag>}, where <real> and
   <imag> must be numerical constants.  For example, {3,2} represents 3










   GNUPLOT 4.1                                                       16


   + 2i; {0,1} represents 'i' itself.  The curly braces are explicitly
   required here.

   Note that gnuplot uses both "real" and "integer" arithmetic, like
   FORTRAN and C.  Integers are entered as "1", "-10", etc; reals as
   "1.0", "-10.0", "1e1", 3.5e-1, etc.  The most important difference
   between the two forms is in division: division of integers trun-
   cates: 5/2 = 2; division of reals does not: 5.0/2.0 = 2.5.  In mixed
   expressions, integers are "promoted" to reals before evaluation:
   5/2e0 = 2.5.  The result of division of a negative integer by a pos-
   itive one may vary among compilers.  Try a test like "print -5/2" to
   determine if your system chooses -2 or -3 as the answer.

   The integer expression "1/0" may be used to generate an "undefined"
   flag, which causes a point to ignored.  Or you can use the pre-
   defined variable NaN to achieve the same result.  See uussiinngg for an
   example.

   The real and imaginary parts of complex expressions are always real,
   whatever the form in which they are entered: in {3,2} the "3" and
   "2" are reals, not integers.

   Gnuplot can also perform simple operations on strings and string
   variables.  For example, the expression ("A" . "B" eq "AB") evalu-
   ates as true, illustrating the string concatenation operator and the
   string equality operator.

   A string which contains a numerical value is promoted to the corre-
   sponding integer or real value if used in a numerical expression.
   Thus ("3" + "4" == 7) and (6.78 == "6.78") both evaluate to true.
   An integer, but not a real or complex value, is promoted to a string
   if used in string concatenation.  A typical case is the use of inte-
   gers to construct file names or other strings; e.g. ("file" . 4 eq
   "file4") is true.

   Substrings can be specified using a postfixed range descriptor
   [beg:end].  For example, "ABCDEF"[3:4] == "CD"   and   "ABCDEF"[4:*]
   == "DEF" The syntax "string"[beg:end] is exactly equivalent to call-
   ing the built-in string-valued function substr("string",beg,end),
   except that you cannot omit either beg or end from the function
   call.




        1155..11..  FFuunnccttiioonnss


        The math functions in ggnnuupplloott are the same as the corresponding
        functions in the Unix math library, except that all functions
        accept integer, real, and complex arguments unless otherwise
        noted.  Functions that accept or return angles (e.g. sin(x),
        cos(x), arg(z)) treat angle values as radians, but this may be










   GNUPLOT 4.1                                                       17


        changed to degrees using the command sseett aanngglleess.






























































   GNUPLOT 4.1                                                       18


   +---------------------------------------------------------------------------------------------------+
   |   Function                Arguments            Returns                                            |
   +---------------------------------------------------------------------------------------------------+
   |    abs(x)                    any               absolute value of _x, |_x|; same type                |
   |    abs(x)                  complex             length of _x, real(_x)2+imag(_x)2                     |
   |    acos(x)                   any               cos-1_x (inverse cosine)                            |
   |   acosh(x)                   any               cosh-1_x (inverse hyperbolic cosine) in radians     |
   |    airy(x)                   any               Airy function Ai(x)                                |
   |    arg(x)                  complex             the phase of _x                                     |
   |    asin(x)                   any               sin-1_x (inverse sin)                               |
   |   asinh(x)                   any               sinh-1_x (inverse hyperbolic sin) in radians        |
   |    atan(x)                   any               tan-1_x (inverse tangent)                           |
   |  atan2(y,x)              int or real           tan-1(_y/_x) (inverse tangent)                       |
   |   atanh(x)                   any               tanh-1_x (inverse hyperbolic tangent) in radians    |
   | EllipticK(k)          real k in (-1:1)         _K_k complete elliptic integral of the first kind    |
   | EllipticE(k)          real k in [-1:1]          _E_k complete elliptic integral of the second kind  |
   |EllipticPi(n,k)    real n<1, real k in (-1:1)    _n,_k complete elliptic integral of the third kind  |
   |   besj0(x)               int or real           _j0 Bessel function of _x, in radians                |
   |   besj1(x)               int or real           _j1 Bessel function of _x, in radians                |
   |   besy0(x)               int or real           _y0 Bessel function of _x, in radians                |
   |   besy1(x)               int or real           _y1 Bessel function of _x, in radians                |
   |    ceil(x)                   any               _x, smallest integer not less than _x (real part)    |
   |    cos(x)                  radians             cos_x, cosine of _x                                  |
   |    cosh(x)                   any               cosh_x, hyperbolic cosine of _x in radians           |
   |    erf(x)                    any               _e_r_f(real(_x)), error function of real (_x)           |
   |    erfc(x)                   any               _e_r_f_c(real(_x)), 1.0 - error function of real (_x)    |
   |    exp(x)                    any               _e_x, exponential function of _x                      |
   |  expint(n,x)                 any               _E_n(_x), exponential integral function of _x          |
   |   floor(x)                   any               _x, largest integer not greater than _x (real part)  |
   |   gamma(x)                   any               (real(_x)), gamma function of real (_x)              |
   | ibeta(p,q,x)                 any               _i_b_e_t_a(real(_p,_q,_x)), ibeta function of real (_p,_q,_x) |
   |   inverf(x)                  any               inverse error function real(_x)                     |
   |  igamma(a,x)                 any               _i_g_a_m_m_a(real(_a,_x)), igamma function of real (_a,_x)   |
   |    imag(x)                 complex             imaginary part of _x as a real number               |
   |  invnorm(x)                  any               inverse normal distribution function real(_x)       |
   |    int(x)                   real               integer part of _x, truncated toward zero           |
   |  lambertw(x)                real               Lambert W function                                 |
   |   lgamma(x)                  any               _l_g_a_m_m_a(real(_x)), lgamma function of real (_x)       |
   |    log(x)                    any               ln_x, natural logarithm (base _e) of _x               |
   |   log10(x)                   any               log10_x, logarithm (base 10) of _x                   |
   |    norm(x)                   any               _n_o_r_m(_x), normal distribution function of real(_x)   |
   |    rand(x)                   int               pseudo random number in the interval [0:1]         |
   |    real(x)                   any               real part of _x                                     |
   |    sgn(x)                    any               1 if _x>0, -1 if _x<0, 0 if _x=0. imag(_x) ignored     |
   |    sin(x)                    any               sin_x, sine of _x                                    |
   |    sinh(x)                   any               sinh_x, hyperbolic sine of _x in radians             |
   |    sqrt(x)                   any               _x, square root of _x                                |
   |    tan(x)                    any               tan_x, tangent of _x                                 |
   |    tanh(x)                   any               tanh_x, hyperbolic tangent of _x in radians          |
   |  voigt(x,y)                 real               convolution of Gaussian and Lorentzian             |
   +---------------------------------------------------------------------------------------------------+












   GNUPLOT 4.1                                                       19


   +---------------------------------------------------------------------------------------------+
   |        Function            Arguments    Returns                                             |
   +---------------------------------------------------------------------------------------------+
   |gprintf("format",x,...)        any       string result from applying gnuplot's format parser |
   |sprintf("format",x,...)     multiple     string result from C-language sprintf               |
   |    strlen("string")         string      int length of string in bytes                       |
   |strstrt("string","key")      strings     int index of first character of substring "key"     |
   |substr("string",beg,end)    multiple     string "string"[beg:end]                            |
   |strftime("timeformat",t)       any       string result from applying gnuplot's time parser   |
   |strptime("timeformat",s)     string      seconds since year 2000 as given in string s        |
   |   system("command")         string      string containing output stream of shell command    |
   |    word("string",n)       string, int   returns the nth word in "string"                    |
   |    words("string")          string      returns the number of words in "string"             |
   +---------------------------------------------------------------------------------------------+






   +--------------------------------------------------------------------------------------------+
   |   Function         Arguments     Returns                                                   |
   +--------------------------------------------------------------------------------------------+
   |   column(x)      int or string    column _x during datafile manipulation.                   |
   | columnhead(x)         int         string containing first entry of column _x in datafile.   |
   |  defined(X)      variable name    [DEPRECATED] returns 1 if X is defined, 0 otherwise.     |
   |  exists("X")        string        returns 1 if a variable named X is defined, 0 otherwise. |
   |stringcolumn(x)   int or string    content column _x as a string.                            |
   | timecolumn(x)         int         timecolumn _x during datafile manipulation.               |
   |  tm_hour(x)           int        the hour                                                  |
   |  tm_mday(x)           int        the day of the month                                      |
   |   tm_min(x)           int        the minute                                                |
   |   tm_mon(x)           int        the month                                                 |
   |   tm_sec(x)           int        the second                                                |
   |  tm_wday(x)           int        the day of the week                                       |
   |  tm_yday(x)           int        the day of the year                                       |
   |  tm_year(x)           int        the year                                                  |
   |    time(x)            any        the current system time                                   |
   |   valid(x)            int         test validity of column(_x) during datafile manip.        |
   | value("name")       string        returns the current value of the named variable.         |
   +--------------------------------------------------------------------------------------------+







             1155..11..11..  EElllliippttiicc iinntteeggrraallss


             The EElllliippttiiccKK((kk)) function returns the complete elliptic
             integral of the first kind, i.e. the definite integral










   GNUPLOT 4.1                                                       20


             between 0 and pi/2 of the function
             ((11--((kk**ssiinn((pp))))****22))****((--00..55)).  The domain of kk is -1 to 1
             (exclusive).

             The EElllliippttiiccEE((kk)) function returns the complete elliptic
             integral of the second kind, i.e. the definite integral
             between 0 and pi/2 of the function ((11--((kk**ssiinn((pp))))****22))****00..55.
             The domain of kk is -1 to 1 (inclusive).

             The EElllliippttiiccPPii((nn,,kk)) function returns the complete elliptic
             integral of the third kind, i.e. the definite integral
             between 0 and pi/2 of the function
             ((11--((kk**ssiinn((pp))))****22))****((--00..55))//((11--nn**ssiinn((pp))****22)).  The parameter
             nn must be less than 1, while kk must lie between -1 and 1
             (exclusive).  Note that by definition EllipticPi(0,k) ==
             EllipticK(k) for all possible values of kk.



             1155..11..22..  RRaannddoomm nnuummbbeerr ggeenneerraattoorr


             The function rraanndd(()) produces a sequence of pseudo-random
             numbers between 0 and 1 using an algorithm from P.
             L'Ecuyer and S. Cote, "Implementing a random number pack-
             age with splitting facilities", ACM Transactions on Mathe-
             matical Software, 17:98-111 (1991).

                   rand(0)     returns a pseudo random number in the
             interval [0:1]
                               generated from the current value of two
             internal
                               32-bit seeds.
                   rand(-1)    resets both seeds to a standard value.
                   rand(x)     for integer 0 < x < 2^31-1 sets both
             internal seeds
                               to x.
                   rand({x,y}) for integer 0 < x,y < 2^31-1 sets seed1
             to x and
                               seed2 to y.



             1155..11..33..  VVaalluuee


             B = value("A") is effectively the same as B = A, where A
             is the name of a user-defined variable.  This is useful
             when the name of the variable is itself held in a string
             variable. See uusseerr--ddeeffiinneedd vvaarriiaabblleess.  It also allows you
             to read the name of a variable from a data file.  If the
             argument is a numerical expression, value() returns the
             value of that expression.  If the argument is a string










   GNUPLOT 4.1                                                       21


             that does not correspond to a currently defined variable,
             value() returns NaN.




        1155..22..  OOppeerraattoorrss


        The operators in ggnnuupplloott are the same as the corresponding
        operators in the C programming language, except that all opera-
        tors accept integer, real, and complex arguments, unless other-
        wise noted.  The ** operator (exponentiation) is supported, as
        in FORTRAN.

        Parentheses may be used to change order of evaluation.




             1155..22..11..  UUnnaarryy


             The following is a list of all the unary operators and
             their usages:







    +-----------------------------------------------------------------+
    |Symbol   Example   Explanation                                   |
    +-----------------------------------------------------------------+
    |  -        -a      unary minus                                   |
    |  +        +a      unary plus (no-operation)                     |
    |  ~        ~a      * one's complement                            |
    |  !        !a      * logical negation                            |
    |  !        a!      * factorial                                   |
    |  $        $3      * call arg/column during `using` manipulation |
    +-----------------------------------------------------------------+
    +-----------------------------------------------------------------+




   (*) Starred explanations indicate that the operator requires an
   integer argument.

   Operator precedence is the same as in Fortran and C.  As in those
   languages, parentheses may be used to change the order of operation.
   Thus -2**2 = -4, but (-2)**2 = 4.










   GNUPLOT 4.1                                                       22


   The factorial operator returns a real number to allow a greater
   range.



             1155..22..22..  BBiinnaarryy


             The following is a list of all the binary operators and
             their usages:




              +--------------------------------------------+
              |Symbol   Example   Explanation              |
              +--------------------------------------------+
              |  **      a**b     exponentiation           |
              |  *        a*b     multiplication           |
              |  /        a/b     division                 |
              |  %        a%b     * modulo                 |
              |  +        a+b     addition                 |
              |  -        a-b     subtraction              |
              |  ==      a==b     equality                 |
              |  !=      a!=b     inequality               |
              |  <        a<b     less than                |
              |  <=      a<=b     less than or equal to    |
              |  >        a>b     greater than             |
              |  >=      a>=b     greater than or equal to |
              |  &        a&b     * bitwise AND            |
              |  ^        a^b     * bitwise exclusive OR   |
              |  |        a|b     * bitwise inclusive OR   |
              |  &&      a&&b     * logical AND            |
              |  ||      a||b     * logical OR             |
              +--------  a = b    assignment               |
              |  ,       (a,b)    serial evaluation        |
              |  eq     A eq B    string equality          |
              |  ne     A ne B    string inequality        |
              +--------------------------------------------+




   (*) Starred explanations indicate that the operator requires integer
   arguments.  Capital letters A and B indicate that the operator
   requires string arguments.

   Logical AND (&&) and OR (||) short-circuit the way they do in C.
   That is, the second &&&& operand is not evaluated if the first is
   false; the second |||| operand is not evaluated if the first is true.

   Serial evaluation occurs only in parentheses and is guaranteed to
   proceed in left to right order.  The value of the rightmost










   GNUPLOT 4.1                                                       23


   subexpression is returned.



             1155..22..33..  TTeerrnnaarryy


             There is a single ternary operator:




                 +---------------------------------------+
                 |Symbol   Example   Explanation         |
                 +---------------------------------------+
                 |  ?:      a?b:c    * ternary operation |
                 +---------------------------------------+




   The ternary operator behaves as it does in C.  The first argument
   (a), which must be an integer, is evaluated.  If it is true (non-
   zero), the second argument (b) is evaluated and returned; otherwise
   the third argument (c) is evaluated and returned.

   The ternary operator is very useful both in constructing piecewise
   functions and in plotting points only when certain conditions are
   met.

   Examples:

   Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <=
   x < 2, and undefined elsewhere:
         f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
         plot f(x)
   Note that ggnnuupplloott quietly ignores undefined values, so the final
   branch of the function (1/0) will produce no plottable points.  Note
   also that f(x) will be plotted as a continuous function across the
   discontinuity if a line style is used.  To plot it discontinuously,
   create separate functions for the two pieces.  (Parametric functions
   are also useful for this purpose.)

   For data in a file, plot the average of the data in columns 2 and 3
   against the datum in column 1, but only if the datum in column 4 is
   non-negative:

         plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )

   For an explanation of the uussiinngg syntax, please see pplloott ddaattaaffiillee
   uussiinngg.












   GNUPLOT 4.1                                                       24


        1155..33..  SSuummmmaattiioonn


        A summation expression has the form
              sum [<var> = <start> : <end>] <expression>
        <var> is treated as an integer variable that takes on succes-
        sive integral values from <start> to <end>.  For each of these,
        the current value of <expression> is added to a running total
        whose final value becomes the value of the summation expres-
        sion.  Examples:
              print sum [i=1:10] i
                  55.
              # Equivalent to plot 'data' using 1:($2+$3+$4+$5+$6+...)
              plot 'data' using 1 : (sum [col=2:MAXCOL] column(col))
        It is not necessary that <expression> contain the variable
        <var>.  Although <start> and <end> can be specified as vari-
        ables or expressions, their value cannot be changed dynamically
        as a side-effect of carrying out the summation. If <end> is
        less than <start> then the value of the summation is zero.



        1155..44..  GGnnuupplloott--ddeeffiinneedd vvaarriiaabblleess


        Gnuplot maintains a number of read-only variables that reflect
        the current internal state of the program and the most recent
        plot. These variables begin with the prefix "GPVAL_".  Examples
        include GPVAL_TERM, GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN.
        Type sshhooww vvaarriiaabblleess aallll to display the complete list and cur-
        rent values.  Values related to axes parameters (ranges, log
        base) are values used during the last plot, not those currently
        sseett.

        Example:  To calculate the fractional screen coordinates of the
        point [X,Y]
             GRAPH_X = (X - GPVAL_X_MIN) / (GPVAL_X_MAX - GPVAL_X_MIN)
             GRAPH_Y = (Y - GPVAL_Y_MIN) / (GPVAL_Y_MAX - GPVAL_Y_MIN)
             SCREEN_X = GPVAL_TERM_XMIN + GRAPH_X * (GPVAL_TERM_XMAX -
        GPVAL_TERM_XMIN)
             SCREEN_Y = GPVAL_TERM_YMIN + GRAPH_Y * (GPVAL_TERM_YMAX -
        GPVAL_TERM_YMIN)
             FRAC_X = SCREEN_X / GPVAL_TERM_XSIZE
             FRAC_Y = SCREEN_Y / GPVAL_TERM_YSIZE

        The read-only variable GPVAL_ERRNO is set to a non-zero value
        if any gnuplot command terminates early due to an error.  The
        most recent error message is stored in the string variable
        GPVAL_ERRMSG.  Both GPVAL_ERRNO and GPVAL_ERRMSG can be cleared
        using the command rreesseett eerrrroorrss.

        Interactive terminals with mmoouussee functionality maintain read-
        only variables with the prefix "MOUSE_".  See mmoouussee vvaarriiaabblleess










   GNUPLOT 4.1                                                       25


        for details.

        The ffiitt mechanism uses several variables with names that begin
        "FIT_".  It is safest to avoid using such names.  "FIT_LIMIT",
        however, is one that you may wish to redefine. Under sseett ffiitt
        eerrrroorrvvaarriiaabblleess, the error for each fitted parameter will be
        stored in a variable named like the parameter, but with "_err"
        appended. See the documentation on ffiitt for details.

        See uusseerr--ddeeffiinneedd vvaarriiaabblleess, rreesseett eerrrroorrss, mmoouussee vvaarriiaabblleess, and
        ffiitt.




        1155..55..  UUsseerr--ddeeffiinneedd vvaarriiaabblleess aanndd ffuunnccttiioonnss


        New user-defined variables and functions of one through twelve
        variables may be declared and used anywhere, including on the
        pplloott command itself.

        User-defined function syntax:
              <func-name>( <dummy1> {,<dummy2>} ... {,<dummy12>} ) =
        <expression>

        where <expression> is defined in terms of <dummy1> through
        <dummy12>.

        User-defined variable syntax:
              <variable-name> = <constant-expression>

        Examples:
              w = 2
              q = floor(tan(pi/2 - 0.1))
              f(x) = sin(w*x)
              sinc(x) = sin(pi*x)/(pi*x)
              delta(t) = (t == 0)
              ramp(t) = (t > 0) ? t : 0
              min(a,b) = (a < b) ? a : b
              comb(n,k) = n!/(k!*(n-k)!)
              len3d(x,y,z) = sqrt(x*x+y*y+z*z)
              plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)

              file = "mydata.inp"
              file(n) = sprintf("run_%d.dat",n)

        The final two examples illustrate a user-defined string vari-
        able and a user-defined string function.

        Note that the variables ppii (3.14159...) and NNaaNN (IEEE "Not a
        Number") are already defined.  You can redefine these to some-
        thing else if you really need to. The original values can be










   GNUPLOT 4.1                                                       26


        recovered by setting:

              NaN = GPVAL_NaN
              pi  = GPVAL_pi

        Other variables may be defined under various gnuplot operations
        like mousing in interactive terminals or fitting; see ggnnuupplloott--
        ddeeffiinneedd vvaarriiaabblleess for details.

        You can check for existence of a given variable V by the
        exists("V") expression. For example
              a = 10
              if (exists("a")) print "a is defined"
              if (!exists("b")) print "b is not defined"

        Valid names are the same as in most programming languages: they
        must begin with a letter, but subsequent characters may be let-
        ters, digits, or "_".

        Each function definition is made available as a special string-
        valued variable with the prefix 'GPFUN_'.

        Example:
              set label GPFUN_sinc at graph .05,.95

        See sshhooww ffuunnccttiioonnss, ffuunnccttiioonnss, ggnnuupplloott--ddeeffiinneedd vvaarriiaabblleess,
        mmaaccrrooss, vvaalluuee.



   1166..  FFoonnttss


   Gnuplot does not provide any fonts of its own. It relies on external
   font handling, the details of which unfortunately vary from one ter-
   minal type to another. Brief documentation of font mechanisms that
   apply to more than one terminal type is given here. For information
   on font use by other individual terminals, see the documentation for
   that terminal.




        1166..11..  CCaaiirroo ((ppddffccaaiirroo,, ppnnggccaaiirroo,, eeppssccaaiirroo,, wwxxtt tteerrmmiinnaallss))


        Sorry, this section is under construction.  These terminals
        find and access fonts using the external fontconfig tool set.
        Please see the fontconfig user manual.  It is usually suffi-
        cient in gnuplot to request a font by a generic name and size,
        letting fontconfig substitute a similar font if necessary. The
        following will probably all work:
             set term pdfcairo font "sans,12"










   GNUPLOT 4.1                                                       27


             set term pdfcairo font "Times,12"
             set term pdfcairo font "Times-New-Roman,12"




        1166..22..  GGdd ((ppnngg,, ggiiff,, jjppeegg tteerrmmiinnaallss))


        Font handling for the png, gif, and jpeg terminals is done by
        the external library libgd.  Five basic fonts are provided
        directly by libgd. These are ttiinnyy (5x8 pixels), ssmmaallll (6x12
        pixels), mmeeddiiuumm, (7x13 Bold), llaarrggee (8x16) or ggiiaanntt (9x15 pix-
        els). These fonts cannot be scaled or rotated.  Use one of
        these keywords instead of the ffoonntt keyword. E.g.
             set term png tiny

        On most systems libgd also provides access to Adobe Type 1
        fonts (*.pfa) and TrueType fonts (*.ttf). You must give the
        name of the font file, not the name of the font inside it, in
        the form "<face> {,<pointsize>}".  <face> is either the full
        pathname to the font file, or the first part of a filename in
        one of the directories listed in the GDFONTPATH environmental
        variable. That is, 'set term png font "Face"' will look for a
        font file named either <somedirectory>/Face.ttf or <somedirec-
        tory>/Face.pfa.  For example, if GDFONTPATH contains
        //uussrr//llooccaall//ffoonnttss//ttttff:://uussrr//llooccaall//ffoonnttss//ppffaa then the following
        pairs of commands are equivalent
             set term png font "arial"
             set term png font "/usr/local/fonts/ttf/arial.ttf"
             set term png font "Helvetica"
             set term png font "/usr/local/fonts/pfa/Helvetica.pfa"
        To request a default font size at the same time:
             set term png font "arial,11"

        Both TrueType and Adobe Type 1 fonts are fully scalable and
        rotatable.  If no specific font is requested in the "set term"
        command, gnuplot checks the environmental variable GNU-
        PLOT_DEFAULT_GDFONT to see if there is a preferred default
        font.



        1166..33..  PPoossttssccrriipptt  ((aallssoo eennccaappssuullaatteedd ppoossttssccrriipptt **..eeppss))


        PostScript font handling is done by the printer or viewing pro-
        gram.  Gnuplot can create valid PostScript or encapsulated
        PostScript (*.eps) even if no fonts at all are installed on
        your computer.  Gnuplot simply refers to the font by name in
        the output file, and assumes that the printer or viewing pro-
        gram will know how to find or approximate a font by that name.











   GNUPLOT 4.1                                                       28


        All PostScript printers or viewers should know about the stan-
        dard set of Adobe fonts TTiimmeess--RRoommaann, HHeellvveettiiccaa, CCoouurriieerr, and
        SSyymmbbooll.  It is likely that many additional fonts are also
        available, but the specific set depends on your system or
        printer configuration. Gnuplot does not know or care about
        this; the output *.ps or *.eps files that it creates will sim-
        ply refer to whatever font names you request.

        Thus
             set term postscript eps font "Times-Roman,12"
        will produce output that is suitable for all printers and view-
        ers.

        On the other hand
             set term postscript eps font "Garamond-Premier-Pro-Italic"
        will produce an output file that contains valid PostScript, but
        since it refers to a specialized font, only some printers or
        viewers will be able to display the specific font that was
        requested.  Most will substitute a different font.

        However, it is possible to embed a specific font in the output
        file so that all printers will be able to use it. This requires
        that the a suitable font description file is available on your
        system. Note that some font files require specific licensing if
        they are to be embedded in this way.  See ppoossttssccrriipptt ffoonnttffiillee
        for more detailed description and examples.



   1177..  GGlloossssaarryy


   Throughout this document an attempt has been made to maintain con-
   sistency of nomenclature.  This cannot be wholly successful because
   as ggnnuupplloott has evolved over time, certain command and keyword names
   have been adopted that preclude such perfection.  This section con-
   tains explanations of the way some of these terms are used.

   A "page" or "screen" or "canvas" is the entire area addressable by
   ggnnuupplloott.  On a desktop it is a full window; on a plotter, it is a
   single sheet of paper; in svga mode it is the full monitor screen.

   A screen may contain one or more "plots".  A plot is defined by an
   abscissa and an ordinate, although these need not actually appear on
   it, as well as the margins and any text written therein.

   A plot contains one "graph".  A graph is defined by an abscissa and
   an ordinate, although these need not actually appear on it.

   A graph may contain one or more "lines".  A line is a single func-
   tion or data set.  "Line" is also a plotting style.  The word will
   also be used in sense "a line of text".  Presumably the context will
   remove any ambiguity.










   GNUPLOT 4.1                                                       29


   The lines on a graph may have individual names.  These may be listed
   together with a sample of the plotting style used to represent them
   in the "key", sometimes also called the "legend".

   The word "title" occurs with multiple meanings in ggnnuupplloott.  In this
   document, it will always be preceded by the adjective "plot",
   "line", or "key" to differentiate among them.  A 2D graph may have
   up to four labelled aaxxeess.  The names of the four axes are "x" for
   the axis along the bottom border of the plot, "y" for the axis along
   the left border, "x2" for the top border, and "y2" for the right
   border.  See aaxxeess.

   A 3D graph may have up to three labelled aaxxeess -- "x", "y" and "z".
   It is not possible to say where on the graph any particular axis
   will fall because you can change the direction from which the graph
   is seen with sseett vviieeww.

   When discussing data files, the term "record" will be resurrected
   and used to denote a single line of text in the file, that is, the
   characters between newline or end-of-record characters.  A "point"
   is the datum extracted from a single record.  A "datablock" is a set
   of points from consecutive records, delimited by blank records.  A
   line, when referred to in the context of a data file, is a subset of
   a datablock.



   1188..  LLiinneettyyppeess,, ccoolloorrss,, aanndd ssttyylleess


   Each gnuplot terminal type provides a set of distinct "linetypes".
   These may differ in color, in thickness, in dot/dash pattern, or in
   some combination of color and dot/dash. The default linetypes for a
   particular terminal can be previewed by issuing the tteesstt command
   after setting the terminal type.  The pre-defined colors and
   dot/dash patterns are not guaranteed to be consistent for all termi-
   nal types, but all terminals use the special linetype -1 to mean a
   solid line in the primary foreground color (normally black).  Most
   terminals also recognize the special linetype "bgnd" to mean a solid
   line in the background color.

   You can redefine the default linetype properties either interac-
   tively or via an initialization file.  This allows you to customize
   the colors and other properties of the lines used by all gnuplot
   plotting commands.  See sseett lliinneettyyppee.

   By default, successive functions or datafiles plotted by a single
   command will be assigned successive linetypes.  You can override
   this default sequence by specifying a particular linetype for any
   function, datafile, or plot element.

   Examples:











   GNUPLOT 4.1                                                       30


        plot "foo", "bar"                 # plot two files using line-
   types 1, 2
        plot sin(x) linetype 4            # terminal-specific linetype
   color 4
        plot sin(x) lt -1                 # black

   For many terminal types it is also possible to assign user-defined
   colors using explicit rgb (red, green, blue) values, named colors,
   or color values that refer to the current pm3d palette.

   Examples:

        plot sin(x) lt rgb "violet"       # one of gnuplot's named col-
   ors
        plot sin(x) lt rgb "#FF00FF"      # explicit RGB triple in
   hexadecimal
        plot sin(x) lt palette cb -45     # whatever color corresponds
   to -45
                                          # in the current cbrange of
   the palette
        plot sin(x) lt palette frac 0.3   # fractional value along the
   palette

   See sshhooww ccoolloorrnnaammeess, sseett ppaalleettttee, ccbbrraannggee.

   For terminals that support dot/dash patterns, each default linetype
   has both a dot-dash pattern and a default color. Gnuplot does not
   currently provide a mechanism for changing the dot-dash pattern, so
   if you want both a particular dash pattern and a particular color
   you must first choose a linetype that has the required dash pattern,
   then override the default color using the keyword lliinneeccoolloorr, abbre-
   viated llcc.  For example, the postscript terminal provides a dashed
   blue line as linetype 3.  The plot commands below use this same dash
   pattern for three plots, one in blue (the default), another in red
   (the default for linetype 1), and a third in gold.

   Example:

        set term postscript dashed color
        plot 'foo' lt 3, 'baz' lt 3 linecolor 1, 'bar' lt 3 lc rgb
   'gold'





        1188..11..  CCoolloorrssppeecc


        Many commands allow you to specify a linetype with an explicit
        color.  Terminal-independent color choice is only possible for
        terminals that support RGB color or pm3d palettes.











   GNUPLOT 4.1                                                       31


        Syntax:

              ... {linecolor | lc} {<colorspec> | <n>}
              ... {textcolor | tc} {<colorspec> | {linetype | lt} <n>}

        where <colorspec> has one of the following forms:

              rgbcolor "colorname"
              rgbcolor "#RRGGBB"
              rgbcolor variable       # color is read from input file
              palette frac <val>      # <val> runs from 0 to 1
              palette cb <value>      # <val> lies within cbrange
              palette z
              variable                # color index is read from input
        file

        The "<n>" is the linetype number the color of which is used,
        see tteesstt.

        "colorname" refers to one of the color names built in to gnu-
        plot. For a list of the available names, see sshhooww ccoolloorrnnaammeess.

        "#RRGGBB" is a hexadecimal constant preceded by the "#" symbol.
        The RRGGBB represents the red, green, and blue components of
        the color, each on a scale from 0 - 255.  For example, magenta
        = full-scale red + full-scale blue would be represented by
        #FF00FF, which is the hexadecimal representation of (255 << 16)
        + (0 << 8) + (255).

        The color palette is a linear gradient of colors that smoothly
        maps a single numerical value onto a particular color.  Two
        such mappings are always in effect. ppaalleettttee ffrraacc  maps a frac-
        tional value between 0 and 1 onto the full range of the color
        palette.  ppaalleettttee ccbb maps the range of the color axis onto the
        same palette.  See sseett ccbbrraannggee.  See also sseett ccoolloorrbbooxx.  You
        can use either of these to select a constant color from the
        current palette.

        "palette z" maps the z value of each plot segment or plot ele-
        ment into the cbrange mapping of the palette. This allows
        smoothly-varying color along a 3d line or surface. It also
        allows coloring 2D plots by palette values read from an extra
        column of data (not all 2D plot styles allow an extra column).




             1188..11..11..  BBaacckkggrroouunndd ccoolloorr


             Most terminals now allow you to set an explicit background
             color for the plot.  The special linetype bbggnndd will draw
             in this color, and bbggnndd is also recognized as a color.










   GNUPLOT 4.1                                                       32


             Examples:
                  # This will erase a section of the canvas by writing
             over it in the
                  # background color
                  set term wxt background rgb "gray75"
                  set object 1 rectangle from x0,y0 to x1,y1 fillstyle
             solid fillcolor bgnd
                  # This will draw an "invisible" line along the x axis
                  plot 0 lt bgnd



             1188..11..22..  LLiinneeccoolloorr vvaarriiaabbllee


             llcc vvaarriiaabbllee tells the program to use the value read from
             one column of the input data as a linetype index, and use
             the color belonging to that linetype.  This requires a
             corresponding additional column in the uussiinngg specifier.
             Text colors can be set similarly using ttcc vvaarriiaabbllee.

             Examples:
                   # Use the third column of data to assign colors to
             individual points
                   plot 'data' using 1:2:3 with points lc variable

                   # A single data file may contain multiple sets of
             data, separated by two
                   # blank lines.  Each data set is assigned as index
             value (see `index`)
                   # that can be retrieved via the `using` specifier
             `column(-2)`.
                   # See `pseudocolumns`.  This example uses to value
             in column -2 to
                   # draw each data set in a different line color.
                   plot 'data' using 1:2:(column(-2)) with lines lc
             variable




             1188..11..33..  RRggbbccoolloorr vvaarriiaabbllee


             You can assign a separate color for each data point, line
             segment, or label in your plot.  llcc rrggbbccoolloorr vvaarriiaabbllee
             tells the program to read RGB color information for each
             line in the data file. This requires a corresponding addi-
             tional column in the uussiinngg specifier.  The extra column is
             interpreted as a 24-bit packed RGB triple. If the value is
             provided directly in the data file it is easiest to give
             it as a hexidecimal value (see rrggbbccoolloorr).  Alternatively,
             the uussiinngg specifier can contain an expression that










   GNUPLOT 4.1                                                       33


             evaluates to a 24-bit RGB color as in the example below.
             Text colors are similarly set using ttcc rrggbbccoolloorr vvaarriiaabbllee.

             Example:
                   # Place colored points in 3D at the x,y,z coordi-
             nates corresponding to
                   # their red, green, and blue components
                   rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
                   splot "data" using 1:2:3:(rgb($1,$2,$3)) with points
             lc rgb variable




        1188..22..  LLiinneessttyylleess vvss lliinneettyyppeess


        Lines can have additional properties such as linewidth.  You
        can associate these various properties, as well as equivalent
        properties for point symbols, into user-defined "linestyles"
        using the command sseett ssttyyllee lliinnee.  Once you have defined a
        linestyle, you can use it in a plot command to control the
        appearance of one or more plot elements.

        Whereas lliinneettyyppeess are permanent (they last until you explicitly
        redefine them), lliinneessttyylleess are temporary.  They only last until
        the next reset of the graphics state.

        Examples:

             # define a new line style with terminal-independent color
        cyan,
             # linewidth 3, and associated point type 6 (a circle with
        a dot in it).
             set style line 5 lt rgb "cyan" lw 3 pt 6
             plot sin(x) with linespoints ls 5          # user-defined
        line style 5




   1199..  MMoouussee iinnppuutt


   Many terminals allow interaction with the current plot using the
   mouse. Some also support the definition of hotkeys to activate pre-
   defined functions by hitting a single key while the mouse focus is
   in the active plot window.  It is even possible to combine mouse
   input with bbaattcchh command scripts, by invoking the command ppaauussee
   mmoouussee and then using the mouse variables returned by mouse clicking
   as parameters for subsequent scripted actions.  See bbiinndd and mmoouussee
   vvaarriiaabblleess.  See also the command sseett mmoouussee.











   GNUPLOT 4.1                                                       34


        1199..11..  BBiinndd


        Syntax:
              bind {allwindows} [<key-sequence>] ["<gnuplot commands>"]
              bind <key-sequence> ""
              reset bind

        The bbiinndd allows defining or redefining a hotkey, i.e. a
        sequence of gnuplot commands which will be executed when a cer-
        tain key or key sequence is pressed while the driver's window
        has the input focus. Note that bbiinndd is only available if gnu-
        plot was compiled with mmoouussee support and it is used by all
        mouse-capable terminals. A user-specified binding supersedes
        any builtin bindings, except that <space> and 'q' cannot nor-
        mally be rebound. For an exception, see bbiinndd ssppaaccee.

        Only mouse button 1 can be bound, and only for 2D plots.

        You get the list of all hotkeys by typing sshhooww bbiinndd or bbiinndd or
        by typing the hotkey 'h' in the graph window.

        Key bindings are restored to their default state by rreesseett bbiinndd.

        Note that multikey-bindings with modifiers must be given in
        quotes.

        Normally hotkeys are only recognized when the currently active
        plot window has focus. bbiinndd aallllwwiinnddoowwss <<kkeeyy>> ...... (short form:
        bbiinndd aallll <<kkeeyy>> ......)  causes the binding for <key> to apply to
        all gnuplot plot windows, active or not.  In this case gnuplot
        variable MOUSE_KEY_WINDOW is set to the ID of the originating
        window, and may be used by the bound command.

        Examples:

        - set bindings:

            bind a "replot"
            bind "ctrl-a" "plot x*x"
            bind "ctrl-alt-a" 'print "great"'
            bind Home "set view 60,30; replot"
            bind all Home 'print "This is window ",MOUSE_KEY_WINDOW'

        - show bindings:
            bind "ctrl-a"          # shows the binding for ctrl-a
            bind                   # shows all bindings
            show bind              # show all bindings

        - remove bindings:
            bind "ctrl-alt-a" ""   # removes binding for ctrl-alt-a
                                     (note that builtins cannot be
        removed)










   GNUPLOT 4.1                                                       35


            reset bind             # installs default (builtin) bind-
        ings
            bind!                  # deprecated form of "reset bind"

        - bind a key to toggle something:
          v=0
          bind "ctrl-r" "v=v+1;if(v%2)set term x11 noraise; else set
        term x11 raise"

        Modifiers (ctrl / alt) are case insensitive, keys not:
            ctrl-alt-a == CtRl-alT-a
            ctrl-alt-a != ctrl-alt-A

        List of modifiers (alt == meta):
            ctrl, alt

        List of supported special keys:

           "BackSpace", "Tab", "Linefeed", "Clear", "Return", "Pause",
        "Scroll_Lock",
           "Sys_Req", "Escape", "Delete", "Home", "Left", "Up",
        "Right", "Down",
           "PageUp", "PageDown", "End", "Begin",

           "KP_Space", "KP_Tab", "KP_Enter", "KP_F1", "KP_F2", "KP_F3",
        "KP_F4",
           "KP_Home", "KP_Left", "KP_Up", "KP_Right", "KP_Down",
        "KP_PageUp",
           "KP_PageDown", "KP_End", "KP_Begin", "KP_Insert",
        "KP_Delete", "KP_Equal",
           "KP_Multiply", "KP_Add", "KP_Separator", "KP_Subtract",
        "KP_Decimal",
           "KP_Divide",

           "KP_1" - "KP_9", "F1" - "F12"

        The following are window events rather than actual keys

           "Button1" "Close"

        See also help for mmoouussee.




             1199..11..11..  BBiinndd ssppaaccee


             If gnuplot was built with configuration option --enable-
             raise-console, then typing <space> in the plot window
             raises gnuplot's command window. This hotkey can be
             changed to ctrl-space by starting gnuplot as 'gnuplot
             -ctrlq', or by setting the XResource 'gnuplot*ctrlq'.  See










   GNUPLOT 4.1                                                       36


             xx1111 ccoommmmaanndd--lliinnee--ooppttiioonnss.



        1199..22..  MMoouussee vvaarriiaabblleess


        When mmoouussiinngg is active, clicking in the active window will set
        several user variables that can be accessed from the gnuplot
        command line. The coordinates of the mouse at the time of the
        click are stored in MOUSE_X MOUSE_Y MOUSE_X2 and MOUSE_Y2. The
        mouse button clicked, and any meta-keys active at that time,
        are stored in MOUSE_BUTTON MOUSE_SHIFT MOUSE_ALT and
        MOUSE_CTRL.  These variables are set to undefined at the start
        of every plot, and only become defined in the event of a mouse
        click in the active plot window. To determine from a script if
        the mouse has been clicked in the active plot window, it is
        sufficient to test for any one of these variables being
        defined.

              plot 'something'
              pause mouse
              if (defined(MOUSE_BUTTON)) call 'something_else'; \
              else print "No mouse click."

        It is also possible to track keystrokes in the plot window
        using the mousing code.

              plot 'something'
              pause mouse keypress
              print "Keystroke ", MOUSE_KEY, " at ", MOUSE_X, " ",
        MOUSE_Y

        When ppaauussee mmoouussee kkeeyypprreessss is terminated by a keypress, then
        MOUSE_KEY will contain the ascii character value of the key
        that was pressed. MOUSE_CHAR will contain the character itself
        as a string variable.  If the pause command is terminated
        abnormally (e.g. by ctrl-C or by externally closing the plot
        window) then MOUSE_KEY will equal -1.

        Note that after a zoom by mouse, you can read the new ranges as
        GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN, and GPVAL_Y_MAX, see
        ggnnuupplloott--ddeeffiinneedd vvaarriiaabblleess.





   2200..  PPlloottttiinngg


   There are three ggnnuupplloott commands which actually create a plot: pplloott,
   sspplloott and rreepplloott.  pplloott generates 2D plots, sspplloott generates 3D plots










   GNUPLOT 4.1                                                       37


   (actually 2D projections, of course), and rreepplloott appends its argu-
   ments to the previous pplloott or sspplloott and executes the modified com-
   mand.

   Much of the general information about plotting can be found in the
   discussion of pplloott; information specific to 3D can be found in the
   sspplloott section.

   pplloott operates in either rectangular or polar coordinates -- see sseett
   ppoollaarr for details of the latter.  sspplloott operates only in rectangular
   coordinates, but the sseett mmaappppiinngg command allows for a few other
   coordinate systems to be treated.  In addition, the uussiinngg option
   allows both pplloott and sspplloott to treat almost any coordinate system
   you'd care to define.

   pplloott also lets you use each of the four borders -- x (bottom), x2
   (top), y (left) and y2 (right) -- as an independent axis.  The aaxxeess
   option lets you choose which pair of axes a given function or data
   set is plotted against.  A full complement of sseett commands exists to
   give you complete control over the scales and labelling of each
   axis.  Some commands have the name of an axis built into their
   names, such as sseett xxllaabbeell.  Other commands have one or more axis
   names as options, such as sseett llooggssccaallee xxyy.  Commands and options
   controlling the z axis have no effect on 2D graphs.

   sspplloott can plot surfaces and contours in addition to points and/or
   lines.  See sseett iissoossaammpplleess for information about defining the grid
   for a 3D function.  See sspplloott ddaattaaffiillee for information about the
   requisite file structure for 3D data values, sseett ccoonnttoouurr and sseett
   ccnnttrrppaarraamm for information about contours.

   In sspplloott, control over the scales and labels of the axes are the
   same as with pplloott, except that commands and options controlling the
   x2 and y2 axes have no effect whereas of course those controlling
   the z axis do take effect.



   2211..  SSttaarrtt--uupp ((iinniittiiaalliizzaattiioonn))


   When gnuplot is run, it first looks for a system-wide initialization
   file named ggnnuupplloottrrcc.  The location of this file is determined when
   the program is built and is reported by sshhooww llooaaddppaatthh.  The program
   then looks in the user's HOME directory for a file called ..ggnnuupplloott
   on Unix-like systems or GGNNUUPPLLOOTT..IINNII on other systems.  (Windows and
   OS/2 will look for it in the directory named in the environment
   variable GGNNUUPPLLOOTT; Windows will use UUSSEERRPPRROOFFIILLEE if GNUPLOT is not
   defined).  Note: The program can be configured to look first in the
   current directory, but this is not recommended because it is bad
   security practice.












   GNUPLOT 4.1                                                       38


   2222..  SSttrriinngg ccoonnssttaannttss aanndd ssttrriinngg vvaarriiaabblleess


   In addition to string constants, most gnuplot commands also accept a
   string variable, a string expression, or a function that returns a
   string.  For example, the following four methods of creating a plot
   all result in the same plot title:

         four = "4"
         graph4 = "Title for plot #4"
         graph(n) = sprintf("Title for plot #%d",n)

         plot 'data.4' title "Title for plot #4"
         plot 'data.4' title graph4
         plot 'data.4' title "Title for plot #".four
         plot 'data.4' title graph(4)

   Since integers are promoted to strings when operated on by the
   string concatenation operator, the following method also works:

         N = 4
         plot 'data.'.N title "Title for plot #".N

   In general, elements on the command line will only be evaluated as
   possible string variables if they are not otherwise recognizable as
   part of the normal gnuplot syntax. So the following sequence of com-
   mands is legal, although probably should be avoided so as not to
   cause confusion:

         plot = "my_datafile.dat"
         title = "My Title"
         plot plot title title

   There are three binary operators that require string operands: the
   string concatenation operator ".", the string equality operator "eq"
   and the string inequality operator "ne".  The following example will
   print TRUE.

        if ("A"."B" eq "AB") print "TRUE"

   See also the two string formatting functions ggpprriinnttff and sspprriinnttff.

   Substrings can be specified by appending a range specifier to any
   string, string variable, or string-valued function.  The range spec-
   ifier has the form [begin:end], where begin is the index of the
   first character of the substring and end is the index of the last
   character of the substring.  The first character has index 1.  The
   begin or end fields may be empty, or contain '*', to indicate the
   true start or end of the original string.  E.g.  str[:] and str[*:*]
   both describe the full string str.













   GNUPLOT 4.1                                                       39


   2233..  SSuubbssttiittuuttiioonn aanndd CCoommmmaanndd lliinnee mmaaccrrooss


   When a command line to gnuplot is first read, i.e. before it is
   interpreted or executed, two forms of lexical substitution are per-
   formed. These are triggered by the presence of text in backquotes
   (ascii character 96) or preceded by @ (ascii character 64).




        2233..11..  SSuubbssttiittuuttiioonn ooff ssyysstteemm ccoommmmaannddss iinn bbaacckkqquuootteess


        Command-line substitution is specified by a system command
        enclosed in backquotes.  This command is spawned and the output
        it produces replaces the backquoted text on the command line.
        Some implementations also support pipes;  see pplloott ddaattaaffiillee
        ssppeecciiaall--ffiilleennaammeess.

        Command-line substitution can be used anywhere on the ggnnuupplloott
        command line, except inside strings delimited by single quotes.

        Example:

        This will run the program lleeaassttssqq and replace lleeaassttssqq (includ-
        ing backquotes) on the command line with its output:
              f(x) = `leastsq`

        or, in VMS
              f(x) = `run leastsq`

        These will generate labels with the current time and userid:
              set label "generated on `date +%Y-%m-%d` by `whoami`" at
        1,1
              set timestamp "generated on %Y-%m-%d by `whoami`"



        2233..22..  SSuubbssttiittuuttiioonn ooff ssttrriinngg vvaarriiaabblleess aass mmaaccrrooss


        Substitution of command line macros is disabled by default, but
        may be enabled using the sseett mmaaccrrooss command.  If macro substi-
        tution is enabled, the character @ is used to trigger substitu-
        tion of the current value of a string variable into the command
        line. The text in the string variable may contain any number of
        lexical elements.  This allows string variables to be used as
        command line macros.  Only string constants may be expanded
        using this mechanism, not string-valued expressions.  For exam-
        ple:

              set macros










   GNUPLOT 4.1                                                       40


              style1 = "lines lt 4 lw 2"
              style2 = "points lt 3 pt 5 ps 2"
              range1 = "using 1:3"
              range2 = "using 1:5"
              plot "foo" @range1 with @style1, "bar" @range2 with
        @style2

        The line containing @ symbols is expanded on input, so that by
        the time it is executed the effect is identical to having typed
        in full

              plot "foo" using 1:3 with lines lt 4 lw 2, \
                   "bar" using 1:5 with points lt 3 pt 5 ps 2

        The function exists() may be useful in connection with macro
        evaluation.  The following example checks that C can safely be
        expanded as the name of a user-defined variable:

              C = "pi"
              if (exists(C)) print C," = ", @C

        Macro expansion does not occur inside either single or double
        quotes.  However macro expansion does occur inside backquotes.

        Macro expansion is handled as the very first thing the inter-
        preter does when looking at a new line of commands and is only
        done once. Therefore, code like the following will execute cor-
        rectly:

             A = "c=1"
             @A

        but this line will not, since the macro is defined on the same
        line and will not be expanded in time

             A = "c=1"; @A   # will not expand to c=1

        For execution of complete commands the eevvaalluuaattee command may
        also be handy.



        2233..33..  SSttrriinngg vvaarriiaabblleess,, mmaaccrrooss,, aanndd ccoommmmaanndd lliinnee ssuubbssttiittuuttiioonn


        The interaction of string variables, backquotes and macro sub-
        stitution is somewhat complicated.  Backquotes do not block
        macro substitution, so

              filename = "mydata.inp"
              lines = ` wc --lines @filename | sed "s/ .*//" `

        results in the number of lines in mydata.inp being stored in










   GNUPLOT 4.1                                                       41


        the integer variable lines. And double quotes do not block
        backquote substitution, so

              mycomputer = "`uname -n`"

        results in the string returned by the system command uunnaammee --nn
        being stored in the string variable mycomputer.

        However, macro substitution is not performed inside double
        quotes, so you cannot define a system command as a macro and
        then use both macro and backquote substitution at the same
        time.

               machine_id = "uname -n"
               mycomputer = "`@machine_id`"  # doesn't work!!

        This fails because the double quotes prevent @machine_id from
        being interpreted as a macro. To store a system command as a
        macro and execute it later you must instead include the back-
        quotes as part of the macro itself.  This is accomplished by
        defining the macro as shown below.  Notice that the sprintf
        format nests all three types of quotes.

              machine_id = sprintf('"`uname -n`"')
              mycomputer = @machine_id



   2244..  SSyynnttaaxx


   Options and any accompanying parameters are separated by spaces
   whereas lists and coordinates are separated by commas.  Ranges are
   separated by colons and enclosed in brackets [], text and file names
   are enclosed in quotes, and a few miscellaneous things are enclosed
   in parentheses.

   Commas are used to separate coordinates on the sseett commands aarrrrooww,
   kkeeyy, and llaabbeell; the list of variables being fitted (the list after
   the vviiaa keyword on the ffiitt command); lists of discrete contours or
   the loop parameters which specify them on the sseett ccnnttrrppaarraamm command;
   the arguments of the sseett commands ddggrriidd33dd, dduummmmyy, iissoossaammpplleess, ooffff--
   sseettss, oorriiggiinn, ssaammpplleess, ssiizzee, ttiimmee, and vviieeww; lists of tics or the
   loop parameters which specify them; the offsets for titles and axis
   labels; parametric functions to be used to calculate the x, y, and z
   coordinates on the pplloott, rreepplloott and sspplloott commands; and the complete
   sets of keywords specifying individual plots (data sets or func-
   tions) on the pplloott, rreepplloott and sspplloott commands.

   Parentheses are used to delimit sets of explicit tics (as opposed to
   loop parameters) and to indicate computations in the uussiinngg filter of
   the ffiitt, pplloott, rreepplloott and sspplloott commands.











   GNUPLOT 4.1                                                       42


   (Parentheses and commas are also used as usual in function nota-
   tion.)

   Square brackets are used to delimit ranges given in sseett, pplloott or
   sspplloott commands.

   Colons are used to separate extrema in rraannggee specifications (whether
   they are given on sseett, pplloott or sspplloott commands) and to separate
   entries in the uussiinngg filter of the pplloott, rreepplloott, sspplloott and ffiitt com-
   mands.

   Semicolons are used to separate commands given on a single command
   line.

   Curly braces are used in the syntax for enhanced text mode and to
   delimit blocks in if/then/else statements.  They are also used to
   denote complex numbers: {3,2} = 3 + 2i.

   The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline
   to be specified by \\ in a single-quoted string or \\\\ in a double-
   quoted string.




        2244..11..  QQuuoottee MMaarrkkss


        Gnuplot uses three forms of quote marks for delimiting text
        strings, double-quote (ascii 34), single-quote (ascii 39), and
        backquote (ascii 96).

        Filenames may be entered with either single- or double-quotes.
        In this manual the command examples generally single-quote
        filenames and double-quote other string tokens for clarity.

        String constants and text strings used for labels, titles, or
        other plot elements may be enclosed in either single quotes or
        double quotes. Further processing of the quoted text depends on
        the choice of quote marks.

        Backslash processing of special characters like \n (newline)
        and \345 (octal character code) is performed for double-quoted
        strings.  In single-quoted strings, backslashes are just ordi-
        nary characters.  To get a single-quote (ascii 39) in a single-
        quoted string, it has to be doubled.  Thus the strings "d\" s'
        b\\" and 'd" s'' b\' are completely equivalent.

        Text justification is the same for each line of a multi-line
        string.  Thus the center-justified string
              "This is the first line of text.\nThis is the second
        line."
        will produce










   GNUPLOT 4.1                                                       43


                               This is the first line of text.
                                  This is the second line.
        but
              'This is the first line of text.\nThis is the second
        line.'
        will produce
                  This is the first line of text.\nThis is the second
        line.

        Enhanced text processing is performed for both double-quoted
        text and single-quoted text, but only by terminals supporting
        this mode.  See eennhhaanncceedd tteexxtt.

        Back-quotes are used to enclose system commands for substitu-
        tion into the command line.  See ssuubbssttiittuuttiioonn.



   2255..  TTiimmee//DDaattee ddaattaa


   ggnnuupplloott supports the use of time and/or date information as input
   data.  This feature is activated by the commands sseett xxddaattaa ttiimmee, sseett
   yyddaattaa ttiimmee, etc.

   Internally all times and dates are converted to the number of sec-
   onds from the year 2000.  The command sseett ttiimmeeffmmtt defines the format
   for all inputs: data files, ranges, tics, label positions---in
   short, anything that accepts a data value must receive it in this
   format.  Since only one input format can be in force at a given
   time, all time/date quantities being input at the same time must be
   presented in the same format.  Thus if both x and y data in a file
   are time/date, they must be in the same format.

   The conversion to and from seconds assumes Universal Time (which is
   the same as Greenwich Standard Time).  There is no provision for
   changing the time zone or for daylight savings.  If all your data
   refer to the same time zone (and are all either daylight or stan-
   dard) you don't need to worry about these things.  But if the abso-
   lute time is crucial for your application, you'll need to convert to
   UT yourself.

   Commands like sshhooww xxrraannggee will re-interpret the integer according to
   ttiimmeeffmmtt.  If you change ttiimmeeffmmtt, and then sshhooww the quantity again,
   it will be displayed in the new ttiimmeeffmmtt.  For that matter, if you
   give the deactivation command (like sseett xxddaattaa), the quantity will be
   shown in its numerical form.

   The commands sseett ffoorrmmaatt or sseett ttiiccss ffoorrmmaatt define the format that
   will be used for tic labels, whether or not the specified axis is
   time/date.

   If time/date information is to be plotted from a file, the uussiinngg










   GNUPLOT 4.1                                                       44


   option _must_ be used on the pplloott or sspplloott command.  These commands
   simply use white space to separate columns, but white space may be
   embedded within the time/date string.  If you use tabs as a separa-
   tor, some trial-and-error may be necessary to discover how your sys-
   tem treats them.

   The ttiimmee function can be used to get the current system time. This
   value can be converted to a date string with the ssttrrffttiimmee function,
   or it can be used in conjunction with ttiimmeeccoolluummnn to generate rela-
   tive time/date plots.  The type of the argument determines what is
   returned. If the argument is an integer, ttiimmee returns the current
   time as an integer, in seconds from 1 Jan 2000. If the argument is
   real (or complex), the result is real as well.  The precision of the
   fractional (sub-second) part depends on your operating system. If
   the argument is a string, it is assumed to be a format string, and
   it is passed to ssttrrffttiimmee to provide a formatted time/date string.

   The following example demonstrates time/date plotting.

   Suppose the file "data" contains records like

         03/21/95 10:00  6.02e23

   This file can be plotted by

         set xdata time
         set timefmt "%m/%d/%y"
         set xrange ["03/21/95":"03/22/95"]
         set format x "%m/%d"
         set timefmt "%m/%d/%y %H:%M"
         plot "data" using 1:3

   which will produce xtic labels that look like "03/21".

   See ttiimmee__ssppeecciiffiieerrss.




   2266..  PPlloottttiinngg ssttyylleess



   There are many plotting styles available in gnuplot.  They are
   listed alphabetically below.  The commands sseett ssttyyllee ddaattaa and sseett
   ssttyyllee ffuunnccttiioonn change the default plotting style for subsequent pplloott
   and sspplloott commands.

   You also have the option to specify the plot style explicitly as
   part of the pplloott or sspplloott command.  If you want to mix plot styles
   within a single plot, you must specify the plot style for each com-
   ponent.











   GNUPLOT 4.1                                                       45


   Example:

        plot 'data' with boxes, sin(x) with lines

   Each plot style has its own expected set of data entries in a data
   file.  For example by default the lliinneess style expects either a sin-
   gle column of y values (with implicit x ordering) or a pair of col-
   umns with x in the first and y in the second.  For more information
   on how to fine-tune how columns in a file are interpreted as plot
   data, see uussiinngg.




   2277..  BBooxxeerrrroorrbbaarrss


   The bbooxxeerrrroorrbbaarrss style is only relevant to 2D data plotting.  It is
   a combination of the bbooxxeess and yyeerrrroorrbbaarrss styles.  It uses 3, 4, or
   5 columns of data:

        3 columns:  x  y  ydelta
        4 columns:  x  y  ydelta xdelta        # boxwidth != -2
        4 columns:  x  y  ylow  yhigh          # boxwidth == -2
        5 columns:  x  y  ylow  yhigh  xdelta

   The boxwidth will come from the fourth column if the y errors are
   given as "ydelta" and the boxwidth was not previously set to -2.0
   (sseett bbooxxwwiiddtthh --22..00) or from the fifth column if the y errors are in
   the form of "ylow yhigh".  The special case  bbooxxwwiiddtthh == --22..00 is for
   four-column data with y errors in the form "ylow yhigh".  In this
   case the boxwidth will be calculated so that each box touches the
   adjacent boxes.  The width will also be calculated in cases where
   three-column data are used.

   An additional (4th, 5th or 6th) input column may be used to provide
   variable (per-datapoint) color information (see lliinneeccoolloorr and rrggbb--
   ccoolloorr vvaarriiaabbllee).  The error bar will be drawn in the same color as
   the border of the box.

   The box height is determined from the y error in the same way as it
   is for the yyeerrrroorrbbaarrss style---either from y-ydelta to y+ydelta or
   from ylow to yhigh, depending on how many data columns are provided.
   See also errorbar demo.



   2288..  BBooxxeess


   The bbooxxeess style is only relevant to 2D plotting.  It draws a box
   centered about the given x coordinate that extends from the x axis
   (not from the graph border) to the given y coordinate.  It uses 2 or










   GNUPLOT 4.1                                                       46


   3 columns of basic data.  Additional input columns may be used to
   provide information such as variable line or fill color (see rrggbb--
   ccoolloorr vvaarriiaabbllee).

        2 columns:  x  y
        3 columns:  x  y  x_width

   The width of the box is obtained in one of three ways.  If the input
   data has a third column, this will be used to set the width of the
   box.  If not, if a width has been set using the sseett bbooxxwwiiddtthh com-
   mand, this will be used.  If neither of these is available, the
   width of each box will be calculated automatically so that it
   touches the adjacent boxes.

   The interior of the boxes is drawn according to the current fill-
   style.  See sseett ssttyyllee ffiillll for details.  Alternatively a new fill-
   style may be specified in the plot command.

   For fillstyle eemmppttyy the box is not filled.

   For fillstyle ssoolliidd the box is filled with a solid rectangle of the
   current drawing color. There is an optional parameter <density> that
   controls the fill density; it runs from 0 (background color) to 1
   (current drawing color).

   For fillstyle ppaatttteerrnn the box is filled in the current drawing color
   with a pattern, if supported by the terminal driver.

   Examples:

   To plot a data file with solid filled boxes with a small vertical
   space separating them (bargraph):

         set boxwidth 0.9 relative
         set style fill solid 1.0
         plot 'file.dat' with boxes

   To plot a sine and a cosine curve in pattern-filled boxes style:

         set style fill pattern
         plot sin(x) with boxes, cos(x) with boxes

   The sin plot will use pattern 0; the cos plot will use pattern 1.
   Any additional plots would cycle through the patterns supported by
   the terminal driver.

   To specify explicit fillstyles for each dataset:

        plot 'file1' with boxes fs solid 0.25, \
             'file2' with boxes fs solid 0.50, \
             'file3' with boxes fs solid 0.75, \
             'file4' with boxes fill pattern 1, \
             'file5' with boxes fill empty










   GNUPLOT 4.1                                                       47


   2299..  BBooxxpplloott


   Boxplots are a common way to represent a statistical distribution of
   values.  Quartile boundaries are determined such that 1/4 of the
   points have a value equal or less than the first quartile boundary,
   1/2 of the points have a value equal or less than the second quar-
   tile (median) value, etc.  A box is drawn around the region between
   the first and third quartiles, with a horizontal line at the median
   value.  Whiskers extend from the box to user-specified limits.
   Points that lie outside these limits are drawn individually.

   Examples

       # Place a boxplot at x coordinate 1.0 representing the y values
   in column 5
       plot 'data' using (1.0):5

       # Same plot but suppress outliers and force the width of the
   boxplot to 0.3
       set style boxplot nooutliers
       plot 'data' using (1.0):5:(0.3)

   By default only one boxplot is produced that represents all y values
   from the second column of the using specification. However, an addi-
   tional (fourth) colunm can be added to the specification. If
   present, the values of that column will be interpreted as the dis-
   crete levels of a factor variable.  As many boxplots will be drawn
   as there are levels in the factor variable.  The separation between
   these boxplots is 1.0 by default, but it can be changed by sseett ssttyyllee
   bbooxxpplloott sseeppaarraattiioonn. By default, the value of the factor variable is
   shown as a tic label below (or above) each boxplot.

   Example

       # Suppose that column 2 of 'data' contains either "control" or
   "treatment"
       # The following example produces two boxplots, one for each
   level of the
       # factor
       plot 'data' using (1.0):5:(0):2

   The default width of the box can be set via sseett bbooxxwwiiddtthh <<wwiiddtthh>> or
   may be specified as an optional 3rd column in the uussiinngg clause of
   the plot command.  The first and third columns (x coordinate and
   width) are normally provided as constants rather than as data col-
   umns.

   By default the whiskers extend from the ends of the box to the most
   distant point whose y value lies within 1.5 times the interquartile
   range. By default outliers are drawn as circles (point type 7).  The
   width of the bars at the end of the whiskers may be controlled using
   sseett bbaarrss.










   GNUPLOT 4.1                                                       48


   These default properties may be changed using the sseett ssttyyllee bbooxxpplloott
   command.  See sseett ssttyyllee bbooxxpplloott, bbaarrss, bbooxxwwiiddtthh, ffiillllssttyyllee, ccaannddllee--
   ssttiicckkss.




   3300..  BBooxxxxyyeerrrroorrbbaarrss


   The bbooxxxxyyeerrrroorrbbaarrss style is only relevant to 2D data plotting.  It
   is similar to the xxyyeerrrroorrbbaarrss style except that it draws rectangular
   areas rather than simple crosses.  It uses either 4 or 6 basic col-
   umns of input data.  Additional input columns may be used to provide
   information such as variable line or fill color (see rrggbbccoolloorr vvaarrii--
   aabbllee).

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   The box width and height are determined from the x and y errors in
   the same way as they are for the xxyyeerrrroorrbbaarrss style---either from
   xlow to xhigh and from ylow to yhigh, or from x-xdelta to x+xdelta
   and from y-ydelta to y+ydelta, depending on how many data columns
   are provided.

   An additional (5th or 7th) input column may be used to provide vari-
   able (per-datapoint) color information (see lliinneeccoolloorr and rrggbbccoolloorr
   vvaarriiaabbllee).

   The interior of the boxes is drawn according to the current fill-
   style.  See sseett ssttyyllee ffiillll and bbooxxeess for details.  Alternatively a
   new fillstyle may be specified in the plot command.



   3311..  CCaannddlleessttiicckkss


   The ccaannddlleessttiicckkss style can be used for 2D data plotting of financial
   data or for generating box-and-whisker plots of statistical data.
   The symbol is a rectangular box, centered horizontally at the x
   coordinate and limited vertically by the opening and closing prices.
   A vertical line segment at the x coordinate extends up from the top
   of the rectangle to the high price and another down to the low.  The
   vertical line will be unchanged if the low and high prices are
   interchanged.

   Five columns of basic data are required:

         financial data:   date  open  low  high  close
         whisker plot:     x  box_min  whisker_min  whisker_high
   box_high










   GNUPLOT 4.1                                                       49


   The width of the rectangle can be controlled by the sseett bbooxxwwiiddtthh
   command.  For backwards compatibility with earlier gnuplot versions,
   when the boxwidth parameter has not been set then the width of the
   candlestick rectangle is controlled by sseett bbaarrss <<wwiiddtthh>>.

   Alternatively, an explicit width for each box-and-whiskers grouping
   may be specified in an optional 6th column of data.  The width must
   be given in the same units as the x coordinate.

   An additional (6th, or 7th if the 6th column is used for width data)
   input column may be used to provide variable (per-datapoint) color
   information (see lliinneeccoolloorr and rrggbbccoolloorr vvaarriiaabbllee).

   By default the vertical line segments have no crossbars at the top
   and bottom. If you want crossbars, which are typically used for box-
   and-whisker plots, then add the keyword wwhhiisskkeerrbbaarrss to the plot com-
   mand.  By default these whiskerbars extend the full horizontal width
   of the candlestick, but you can modify this by specifying a fraction
   of the full width.

   The usual convention for financial data is that the rectangle is
   empty if (open < close) and solid fill if (close < open). This is
   the behavior you will get if the current fillstyle is set to
   "empty". See ffiillllssttyyllee.  If you set the fillstyle to solid or pat-
   tern, then this will be used for all boxes independent of open and
   close values.  See also sseett bbaarrss and ffiinnaanncceebbaarrss.  See also the can-
   dlestick and finance demos.

   Note: To place additional symbols, such as the median value, on a
   box-and-whisker plot requires additional plot commands as in this
   example:

     # Data columns:X Min 1stQuartile Median 3rdQuartile Max
     set bars 4.0
     set style fill empty
     plot 'stat.dat' using 1:3:2:6:5 with candlesticks title 'Quar-
   tiles', \
          ''         using 1:4:4:4:4 with candlesticks lt -1 notitle

     # Plot with crossbars on the whiskers, crossbars are 50% of full
   width
     plot 'stat.dat' using 1:3:2:6:5 with candlesticks whiskerbars 0.5

   See sseett bbooxxwwiiddtthh, sseett bbaarrss, sseett ssttyyllee ffiillll, and bbooxxpplloott.



   3322..  CCiirrcclleess


   The cciirrcclleess style plots a circle with an explicit radius at each
   data point.  If three columns of data are present, they are inter-
   preted as x, y, radius.  The radius is always interpreted in the










   GNUPLOT 4.1                                                       50


   units of the plot's horizontal axis (x or x2).  The scale on y and
   the aspect ratio of the plot are both ignored.  If only two columns
   are present, the radius is taken from sseett ssttyyllee cciirrccllee.  In this
   case the radius may be given in graph or screen coordinates.  By
   default a full circle will be drawn.  It is possible to plot arc
   segments instead of full circles by specifying a start and end angle
   in the 4th and 5th columns.  An optional 4th or 6th column can spec-
   ify per-circle color.  The start and end angles of the circle seg-
   ments must be specified in degrees.


   Examples:

       # draws circles whose area is proportional to the value in col-
   umn 3
       set style fill transparent solid 0.2 noborder
       plot 'data' using 1:2:(sqrt($3)) with circles, \
            'data' using 1:2 with linespoints

       # draws Pac-men instead of circles
       plot 'data' using 1:2:(10):(40):(320) with circles

       # draw a pie chart with inline data
       set xrange [-15:15]
       set style fill transparent solid 0.9 noborder
       plot '-' using 1:2:3:4:5:6 with circles lc var
       0    0    5    0    30    1
       0    0    5   30    70    2
       0    0    5   70   120    3
       0    0    5  120   230    4
       0    0    5  230   360    5
       e

   The result is similar to using a ppooiinnttss plot with variable size
   points and pointstyle 7, except that the circles will scale with the
   x axis range.  See also sseett oobbjjeecctt cciirrccllee and ffiillllssttyyllee.



   3333..  EElllliippsseess


   The eelllliippsseess style plots an ellipse at each data point.  This style
   is only relevant for 2D plotting.  Each ellipse is described in
   terms of its center, major and minor diameters, and the angle
   between its major diameter and the x axis.

        2 columns: x y
        3 columns: x y major_diam
        4 columns: x y major_diam minor_diam
        5 columns: x y major_diam minor_diam angle

   If only two input columns are present, they are taken as the










   GNUPLOT 4.1                                                       51


   coordinates of the centers, and the ellipses will be drawn with the
   default extent (see sseett ssttyyllee eelllliippssee).  The orientation of the
   ellipse, which is defined as the angle between the major diameter
   and the plot's x axis, is taken from the default ellipse style (see
   sseett ssttyyllee eelllliippssee).  If three input columns are provided, the third
   column is used for both diameters.  The orientation angle defaults
   to zero.  If four columns are present, they are interpreted as x, y,
   major diameter, minor diameter.  Note that these are diameters, not
   radii.  An optional 5th column may be used to specify the orienta-
   tion angle in degrees.  The ellipses will also be drawn with their
   default extent if either of the supplied diameters in the 3-4-5 col-
   umn form is negative.

   In all of the above cases, optional variable color data may be given
   in an additional last (3th, 4th, 5th or 6th) column. See ccoolloorrssppeecc
   for further information.

   By default, the major diameter is interpreted in the units of the
   plot's horizontal axis (x or x2) while the minor diameter in that of
   the vertical (y or y2).  This implies that if the x and y axis
   scales are not equal, then the major/minor diameter ratio will no
   longer be correct after rotation.  This behavior can be changed with
   the uunniittss keyword, however.

   There are three alternatives: if uunniittss xxyy is included in the plot
   specification, the axes will be scaled as described above. uunniittss xxxx
   ensures that both diameters are interpreted in units of the x axis,
   while uunniittss yyyy means that both diameters are interpreted in units of
   the y axis. In the latter two cases the ellipses will have the cor-
   rect aspect ratio, even if the plot is resized.

   If uunniittss is omitted, the default setting will be used, which is
   equivalent to uunniittss xxyy. This can be redefined by sseett ssttyyllee eelllliippssee.

   Example (draws ellipses, cycling through the available line types):

       plot 'data' using 1:2:3:4:(0):0 with ellipses

   See also sseett oobbjjeecctt eelllliippssee, sseett ssttyyllee eelllliippssee and ffiillllssttyyllee.



   3344..  DDoottss


   The ddoottss style plots a tiny dot at each point; this is useful for
   scatter plots with many points.  Either 1 or 2 columns of input data
   are required in 2D.  Three columns are required in 3D.

   For some terminals (post, pdf) the size of the dot can be controlled
   by changing the linewidth.

        1 column    y         # x is row number










   GNUPLOT 4.1                                                       52


        2 columns:  x  y
        3 columns:  x  y  z   # 3D only (splot)




   3355..  FFiilllleeddccuurrvveess


   The ffiilllleeddccuurrvveess style is only relevant to 2D plotting. Three vari-
   ants are possible. The first two variants require either a function
   or two columns of input data, and may be further modified by the
   options listed below.

   Syntax:

       plot ... with filledcurves [option]

   where the option can be one of the following

       [closed | {above | below}
       {x1 | x2 | y1 | y2 | r}[=<a>] | xy=<x>,<y>]

   The first variant, cclloosseedd, treats the curve itself as a closed poly-
   gon.  This is the default if there are two columns of input data.

   The second variant is to fill the area between the curve and a given
   axis, a horizontal or vertical line, or a point.

       filledcurves closed   ... just filled closed curve,
       filledcurves x1       ... x1 axis,
       filledcurves x2       ... x2 axis, etc for y1 and y2 axes,
       filledcurves y1=0     ... line y=0 (at y1 axis) ie parallel to
   x1 axis,
       filledcurves y2=42    ... line y=42 (at y2 axis) ie parallel to
   x2, etc,
       filledcurves xy=10,20 ... point 10,20 of x1,y1 axes (arc-like
   shape).
       filledcurves above r=1.5  the area of a polar plot outside
   radius 1.5

   The third variant requires three columns of input data: the x coor-
   dinate and two y coordinates corresponding to two curves sampled at
   the same set of x coordinates; the area between the two curves is
   filled.  This is the default if there are three or more columns of
   input data.

        3 columns:  x  y1  y2

   Example of filling the area between two input curves.  fill between
   curves demo.

       plot 'data' using 1:2:3 with filledcurves










   GNUPLOT 4.1                                                       53


   The aabboovvee and bbeellooww options apply both to commands of the form
       ... filledcurves above {x1|x2|y1|y2|r}=<val>
   and to commands of the form
       ... using 1:2:3 with filledcurves below
   In either case the option limits the filled area to one side of the
   bounding line or curve.

   Note: Not all terminal types support this plotting mode.

   Zooming a filled curve drawn from a datafile may produce empty or
   incorrect areas because gnuplot is clipping points and lines, and
   not areas.

   If the values of <a>, <x>, <y> are out of the drawing boundary, then
   they are moved to the graph boundary. Then the actually filled area
   in the case of option xy=<x>,<y> will depend on xrange and yrange.



   3366..  FFiinnaanncceebbaarrss


   The ffiinnaanncceebbaarrss style is only relevant for 2D data plotting of
   financial data.  It requires 1 x coordinate (usually a date) and 4 y
   values (prices).

        5 columns:   date  open  low  high  close

   An additional (6th) input column may be used to provide variable
   (per-record) color information (see lliinneeccoolloorr and rrggbbccoolloorr vvaarrii--
   aabbllee).

   The symbol is a vertical line segment, located horizontally at the x
   coordinate and limited vertically by the high and low prices.  A
   horizontal tic on the left marks the opening price and one on the
   right marks the closing price.  The length of these tics may be
   changed by sseett bbaarrss.  The symbol will be unchanged if the high and
   low prices are interchanged.  See sseett bbaarrss and ccaannddlleessttiicckkss, and
   also the finance demo.



   3377..  FFsstteeppss


   The ffsstteeppss style is only relevant to 2D plotting.  It connects con-
   secutive points with two line segments: the first from (x1,y1) to
   (x1,y2) and the second from (x1,y2) to (x2,y2).  The input column
   requires are the same as for plot styles lliinneess and ppooiinnttss.  The dif-
   ference between ffsstteeppss and sstteeppss is that ffsstteeppss traces first the
   change in y and then the change in x.  sstteeppss traces first the change
   in x and then the change in y.











   GNUPLOT 4.1                                                       54


   See also steps demo.



   3388..  FFiillllsstteeppss


   The ffiillllsstteeppss style is exactly like sstteeppss except that the area
   between the curve and y=0 is filled in the current fill style.  See
   sstteeppss.



   3399..  HHiisstteeppss


   The hhiisstteeppss style is only relevant to 2D plotting.  It is intended
   for plotting histograms.  Y-values are assumed to be centered at the
   x-values; the point at x1 is represented as a horizontal line from
   ((x0+x1)/2,y1) to ((x1+x2)/2,y1).  The lines representing the end
   points are extended so that the step is centered on at x.  Adjacent
   points are connected by a vertical line at their average x, that is,
   from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).  The input column requires
   are the same as for plot styles lliinneess and ppooiinnttss.

   If aauuttoossccaallee is in effect, it selects the xrange from the data
   rather than the steps, so the end points will appear only half as
   wide as the others.  See also steps demo.

   hhiisstteeppss is only a plotting style; ggnnuupplloott does not have the ability
   to create bins and determine their population from some data set.



   4400..  HHiissttooggrraammss


   The hhiissttooggrraammss style is only relevant to 2D plotting.  It produces a
   bar chart from a sequence of parallel data columns. Each element of
   the pplloott command must specify a single input data source (e.g. one
   column of the input file), possibly with associated tic values or
   key titles.  Four styles of histogram layout are currently sup-
   ported.

         set style histogram clustered {gap <gapsize>}
         set style histogram errorbars {gap <gapsize>} {<linewidth>}
         set style histogram rowstacked
         set style histogram columnstacked

   The default style corresponds to sseett ssttyyllee hhiissttooggrraamm cclluusstteerreedd ggaapp
   22.  In this style, each set of parallel data values is collected
   into a group of boxes clustered at the x-axis coordinate correspond-
   ing to their sequential position (row #) in the selected datafile










   GNUPLOT 4.1                                                       55


   columns.  Thus if <n> datacolumns are selected, the first cluster is
   centered about x=1, and contains <n> boxes whose heights are taken
   from the first entry in the corresponding <n> data columns.  This is
   followed by a gap and then a second cluster of boxes centered about
   x=2 corresponding to the second entry in the respective data col-
   umns, and so on.  The default gap width of 2 indicates that the
   empty space between clusters is equivalent to the width of 2 boxes.
   All boxes derived from any one column are given the same fill color
   and/or pattern (see sseett ssttyyllee ffiillll).

   Each cluster of boxes is derived from a single row of the input data
   file.  It is common in such input files that the first element of
   each row is a label. Labels from this column may be placed along the
   x-axis underneath the appropriate cluster of boxes with the xxttiiccllaa--
   bbeellss option to uussiinngg.

   The eerrrroorrbbaarrss style is very similar to the cclluusstteerreedd style, except
   that it requires additional columns of input for each entry. The
   first column holds the height (y value) of that box, exactly as for
   the cclluusstteerreedd style.
        2 columns:        y yerr          bar extends from y-yerr to
   y+err
        3 columns:        y ymin yman     bar extends from ymin to ymax
   The appearance of the error bars is controlled by the current value
   of sseett bbaarrss and by the optional <linewidth> specification.

   Two styles of stacked histogram are supported, chosen by the command
   sseett ssttyyllee hhiissttooggrraamm {{rroowwssttaacckkeedd||ccoolluummnnssttaacckkeedd}}.  In these styles the
   data values from the selected columns are collected into stacks of
   boxes.  Positive values stack upwards from y=0; negative values
   stack downwards.  Mixed positive and negative values will produce
   both an upward stack and a downward stack.  The default stacking
   mode is rroowwssttaacckkeedd.

   The rroowwssttaacckkeedd style places a box resting on the x-axis for each
   data value in the first selected column; the first data value
   results in a box a x=1, the second at x=2, and so on.  Boxes corre-
   sponding to the second and subsequent data columns are layered on
   top of these, resulting in a stack of boxes at x=1 representing the
   first data value from each column, a stack of boxes at x=2 repre-
   senting the second data value from each column, and so on.  All
   boxes derived from any one column are given the same fill color
   and/or pattern (see sseett ssttyyllee ffiillll).

   The ccoolluummnnssttaacckkeedd style is similar, except that each stack of boxes
   is built up from a single data column. Each data value from the
   first specified column yields a box in the stack at x=1, each data
   value from the second specified column yields a box in the stack at
   x=2, and so on.  In this style the color of each box is taken from
   the row number, rather than the column number, of the corresponding
   data field.

   Box widths may be modified using the sseett bbooxxwwiiddtthh command.  Box fill










   GNUPLOT 4.1                                                       56


   styles may be set using the sseett ssttyyllee ffiillll command.

   Histograms always use the x1 axis, but may use either y1 or y2.  If
   a plot contains both histograms and other plot styles, the non-his-
   togram plot elements may use either the x1 or the x2 axis.

   Examples: Suppose that the input file contains data values in col-
   umns 2, 4, 6, ...  and error estimates in columns 3, 5, 7, ...  This
   example plots the values in columns 2 and 4 as a histogram of clus-
   tered boxes (the default style).  Because we use iteration in the
   plot command, any number of data columns can be handled in a single
   command. See iitteerraattiioonn.

         set boxwidth 0.9 relative
         set style data histograms
         set style histogram cluster
         set style fill solid 1.0 border lt -1
         plot for [COL=2:4:2] 'file.dat' using COL

   This will produce a plot with clusters of two boxes (vertical bars)
   centered at each integral value on the x axis.  If the first column
   of the input file contains labels, they may be placed along the x-
   axis using the variant command

         plot for [COL=2:4:2] 'file.dat' using COL:xticlabels(1)

   If the file contains both magnitude and range information for each
   value, then error bars can be added to the plot.  The following com-
   mands will add error bars extending from (y-<error>) to (y+<error>),
   capped by horizontal bar ends drawn the same width as the box
   itself. The error bars and bar ends are drawn with linewidth 2,
   using the border linetype from the current fill style.

         set bars fullwidth
         set style fill solid 1 border lt -1
         set style histogram errorbars gap 2 lw 2
         plot for [COL=2:4:2] 'file.dat' using COL:COL+1

   To plot the same data as a rowstacked histogram.  Just to be differ-
   ent, this example lists the separate columns explicitly rather than
   using iteration.

         set style histogram rowstacked
         plot 'file.dat' using 2, '' using 4:xtic(1)

   This will produce a plot in which each vertical bar corresponds to
   one row of data.  Each vertical bar contains a stack of two seg-
   ments, corresponding in height to the values found in columns 2 and
   4 of the datafile.


   Finally, the commands











   GNUPLOT 4.1                                                       57


         set style histogram columnstacked
         plot 'file.dat' using 2, '' using 4

   will produce two vertical stacks, one for each column of data.  The
   stack at x=1 will contain a box for each entry in column 2 of the
   datafile.  The stack at x=2 will contain a box for each parallel
   entry in column 4 of the datafile.  Because this interchanges gnu-
   plot's usual interpretation of input rows and columns, the specifi-
   cation of key titles and x-axis tic labels must also be modified
   accordingly. See the comments given below.

         set style histogram columnstacked
         plot '' u 5:key(1)            # uses first column to generate
   key titles
         plot '' u 5 title columnhead  # uses first row to generate
   xtic labels

   Note that the two examples just given present exactly the same data
   values, but in different formats.




        4400..11..  NNeewwhhiissttooggrraamm


        Syntax:

             newhistogram {"<title>"} {lt <linetype>} {fs <fillstyle>}
        {at <x-coord>}

        More than one set of histograms can appear in a single plot. In
        this case you can force a gap between them, and a separate
        label for each set, by using the nneewwhhiissttooggrraamm command.  For
        example

              set style histogram  cluster
              plot newhistogram "Set A", 'a' using 1, '' using 2, ''
        using 3, \
                   newhistogram "Set B", 'b' using 1, '' using 2, ''
        using 3

        The labels "Set A" and "Set B" will appear beneath the respec-
        tive sets of histograms, under the overall x axis label.

        The newhistogram command can also be used to force histogram
        coloring to begin with a specific color (linetype). By default
        colors will continue to increment successively even across his-
        togram boundaries. Here is an example using the same coloring
        for multiple histograms
              plot newhistogram "Set A" lt 4, 'a' using 1, '' using 2,
        '' using 3, \
                   newhistogram "Set B" lt 4, 'b' using 1, '' using 2,










   GNUPLOT 4.1                                                       58


        '' using 3

        Similarly you can force the next histogram to begin with a
        specified fillstyle.  If the fillstyle is set to ppaatttteerrnn, then
        the pattern used for filling will be incremented automatically.

        The aatt <<xx--ccoooorrdd>> option sets the x coordinate position of the
        following histogram to <x-coord>. For example

               set style histogram cluster
               set style data histogram
               set style fill solid 1.0 border -1
               set xtic 1 offset character 0,0.3
               plot newhistogram "Set A", \
                    'file.dat' u 1 t 1, '' u 2 t 2, \
                    newhistogram "Set B" at 8, \
                    'file.dat' u 2 t 2, '' u 2 t 2

        will position the second histogram to start at x=8.



        4400..22..  AAuuttoommaatteedd iitteerraattiioonn oovveerr mmuullttiippllee ccoolluummnnss


        If you want to create a histogram from many columns of data in
        a single file, it is very convenient to use the plot iteration
        feature.  See iitteerraattiioonn.  For example, to create stacked his-
        tograms of the data in columns 3 through 8

              set style histogram columnstacked
              plot for [i=3:8] "datafile" using i title columnhead



   4411..  IImmaaggee


   The iimmaaggee, rrggbbiimmaaggee, and rrggbbaallpphhaa plotting styles all project a uni-
   formly sampled grid of data values onto a plane  in either 2D or 3D.
   The input data may be an actual bitmapped image, perhaps converted
   from a standard format such as PNG, or a simple array of numerical
   values.

   This figure illustrates generation of a heat map from an array of
   scalar values.  The current palette is used to map each value onto
   the color assigned to the corresponding pixel.
         plot '-' matrix with image
         5 4 3 1 0
         2 2 0 0 1
         0 0 0 1 0
         0 1 2 4 3
         e










   GNUPLOT 4.1                                                       59


         e

   Each pixel (data point) of the input 2D image will become a rectan-
   gle or parallelipiped in the plot. The coordinates of each data
   point will determine the center of the parallelipiped.  That is, an
   M x N set of data will form an image with M x N pixels.  This is
   different from the pm3d plotting style, where an M x N set of data
   will form a surface of (M-1) x (N-1) elements.  The scan directions
   for a binary image data grid can be further controlled by additional
   keywords. See bbiinnaarryy kkeeyywwoorrddss fflliippxx, kkeeyywwoorrddss cceenntteerr, and kkeeyywwoorrddss
   rroottaattee.

   Image data can be scaled to fill a particular rectangle within a 2D
   plot coordinate system by specifying the x and y extent of each
   pixel.  See bbiinnaarryy kkeeyywwoorrddss ddxx and ddyy. To generate the figure at the
   right, the same input image was placed multiple times, each with a
   specified dx, dy, and origin. The input PNG image of a building is
   50x128 pixels.  The tall building was drawn by mapping this using
   ddxx==00..55 ddyy==11..55.  The short building used a mapping ddxx==00..55 ddyy==00..3355.

   The iimmaaggee style handles input pixels containing a grayscale or color
   palette value. Thus 2D plots (pplloott command) require 3 columns of
   data (x,y,value), while 3D plots (sspplloott command) require 4 columns
   of data (x,y,z,value).

   The rrggbbiimmaaggee style handles input pixels that are described by three
   separate values for the red, green, and blue components.  Thus 5D
   data (x,y,r,g,b) is needed for pplloott and 6D data (x,y,z,r,g,b) for
   sspplloott.  The individual red, green, and blue components are assumed
   to lie in the range [0:255].

   The rrggbbaallpphhaa style handles input pixels that contain alpha channel
   (transparency) information in addition to the red, green, and blue
   components.  Thus 6D data (x,y,r,g,b,a) is needed for pplloott and 7D
   data (x,y,z,r,g,b,a) for sspplloott.  The r, g, b, and alpha components
   are assumed to lie in the range [0:255].




        4411..11..  TTrraannssppaarreennccyy


        The rrggbbaallpphhaa plotting style assumes that each pixel of input
        data contains an alpha value in the range [0:255].  A pixel
        with alpha = 0 is purely transparent and does not alter the
        underlying contents of the plot. A pixel with alpha = 255 is
        purely opaque.  All terminal types can handle these two extreme
        cases.  A pixel with 0 < alpha < 255 is partially transparent.
        Only a few terminal types can handle this correctly; other ter-
        minals will approximate this by treating alpha as being either
        0 or 255.











   GNUPLOT 4.1                                                       60


        4411..22..  IImmaaggee ffaaiillssaaffee


        Some terminal drivers provide code to optimize rendering of
        image data within a rectangular 2D area.  However this code is
        known to be imperfect.  This optimized code may be disabled by
        using the keyword ffaaiillssaaffee. E.g.

              plot 'data' with image failsafe



   4422..  IImmppuullsseess


   The iimmppuullsseess style displays a vertical line from y=0 to the y value
   of each point (2D) or from z=0 to the z value of each point (3D).
   Note that the y or z values may be negative.  Data from additional
   columns can be used to control the color of each impulse.  To use
   this style effectively in 3D plots, it is useful to choose thick
   lines (linewidth > 1). This approximates a 3D bar chart.

        1 column:   y
        2 columns:  x  y     # line from [x,0] to [x,y]  (2D)
        3 columns:  x  y  z  # line from [x,y,0] to [x,y,z] (3D)




   4433..  LLaabbeellss


   The llaabbeellss style reads coordinates and text from a data file and
   places the text string at the corresponding 2D or 3D position.  3 or
   4 input columns of basic data are required.  Additional input col-
   umns may be used to provide information such as variable font size
   or text color (see rrggbbccoolloorr vvaarriiaabbllee).

        3 columns:  x  y  string    # 2D version
        4 columns:  x  y  z  string # 3D version

   The font, color, rotation angle and other properties of the printed
   text may be specified as additional command options (see sseett llaabbeell).
   The example below generates a 2D plot with text labels constructed
   from the city whose name is taken from column 1 of the input file,
   and whose geographic coordinates are in columns 4 and 5. The font
   size is calculated from the value in column 3, in this case the pop-
   ulation.

     CityName(String,Size) = sprintf("{/=%d %s}", Scale(Size), String)
     plot 'cities.dat' using 5:4:(CityName(stringcolumn(1),$3)) with
   labels











   GNUPLOT 4.1                                                       61


   If we did not want to adjust the font to a different size for each
   city, the command would be much simpler:

     plot 'cities.dat' using 5:4:1 with labels font "Times,8"

   The llaabbeellss style can also be used in 3D plots. In this case four
   input column specifiers are required, corresponding to X Y Z and
   text.

     splot 'datafile' using 1:2:3:4 with labels

   See also ddaattaassttrriinnggss, sseett ssttyyllee ddaattaa.



   4444..  LLiinneess


   The lliinneess style connects adjacent points with straight line seg-
   ments.  It may be used in either 2D or 3D plots. The basic form
   requires 1, 2, or 3 columns of input data.  Additional input columns
   may be used to provide information such as variable line color (see
   rrggbbccoolloorr vvaarriiaabbllee).

   2D form
        1 column:   y       # implicit x from row number
        2 columns:  x  y
   3D form
        1 column:   z       # implicit x from row, y from index
        3 columns:  x  y  z

   See also lliinneettyyppee, lliinneewwiiddtthh, and lliinneessttyyllee.



   4455..  LLiinneessppooiinnttss


   The lliinneessppooiinnttss style connects adjacent points with straight line
   segments and then goes back to draw a small symbol at each point.
   The command sseett ppooiinnttssiizzee may be used to change the default size of
   the points.  1 or 2 columns of basic input data are required in 2D
   plots; 1 or 3 columns are required if 3D plots.  See ssttyyllee lliinneess.
   Additional input columns may be used to provide information such as
   variable point size or line color.

   The ppooiinnttiinntteerrvvaall (short form ppii) property of the linetype can be
   used to control whether or not every point in the plot is given a
   symbol.  For example, 'with lp pi 3' will draw line segments through
   every data point, but will only place a symbol on every 3rd point.
   A negative value for ppooiinnttiinntteerrvvaall will erase the portion of line
   segment that passes underneath the symbol. The size of the erased
   portion is controlled by sseett ppooiinnttiinntteerrvvaallbbooxx.










   GNUPLOT 4.1                                                       62


   lliinneessppooiinnttss may be abbreviated llpp.



   4466..  PPooiinnttss


   The ppooiinnttss style displays a small symbol at each point.  The command
   sseett ppooiinnttssiizzee may be used to change the default size of the points.
   1 or 2 columns of basic input data are required in 2D plots; 1 or 3
   columns are required in 3D plots.  See ssttyyllee lliinneess.  Additional
   input columns may be used to provide information such as variable
   point size or variable point color.




   4477..  PPoollaarr


   Polar plots are not really a separate plot style but are listed here
   for completeness.  The option sseett ppoollaarr tells gnuplot to interpret
   input 2D coordinates as <angle>,<radius> rather than <x>,<y>.  Many,
   but not all, 2D plotting styles work in polar mode.  The figure
   shows a combination of plot styles lliinneess and ffiilllleeddccuurrvveess.  See sseett
   ppoollaarr, sseett rrrraannggee, sseett ssiizzee ssqquuaarree.




   4488..  SStteeppss


   The sstteeppss style is only relevant to 2D plotting.  It connects con-
   secutive points with two line segments: the first from (x1,y1) to
   (x2,y1) and the second from (x2,y1) to (x2,y2).  The input column
   requires are the same as for plot styles lliinneess and ppooiinnttss.  The dif-
   ference between ffsstteeppss and sstteeppss is that ffsstteeppss traces first the
   change in y and then the change in x.  sstteeppss traces first the change
   in x and then the change in y.  To fill the area between the curve
   and the baseline at y=0, use ffiillllsstteeppss.  See also steps demo.




   4499..  RRggbbaallpphhaa


   See iimmaaggee.














   GNUPLOT 4.1                                                       63


   5500..  RRggbbiimmaaggee


   See iimmaaggee.



   5511..  VVeeccttoorrss


   The 2D vveeccttoorrss style draws a vector from (x,y) to
   (x+xdelta,y+ydelta).  The 3D vveeccttoorrss style is similar, but requires
   six columns of basic data.  A small arrowhead is drawn at the end of
   each vector.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  z  xdelta  ydelta  zdelta

   In both cases, an additional input column (5th in 2D, 7th in 3D) may
   be used to provide variable (per-datapoint) color information.  (see
   lliinneeccoolloorr and rrggbbccoolloorr vvaarriiaabbllee).

   splot with vectors is supported only for sseett mmaappppiinngg ccaarrtteessiiaann.

   The keywords "with vectors" may be followed by an in-line arrow
   style specifications, a reference to a predefined arrow style, or a
   request to read the index of the desired arrow style for each vector
   from a separate column.  Note: If you choose "arrowstyle variable"
   it will fill in all arrow properties at the time the corresponding
   vector is drawn; you cannot mix this keyword with other line or
   arrow style qualifiers in the plot command.

        plot ... with vectors filled heads
        plot ... with vectors arrowstyle 3
        plot ... using 1:2:3:4:5 with vectors arrowstyle variable

   See aarrrroowwssttyyllee for more details.

   Example:
         plot 'file.dat' using 1:2:3:4 with vectors head filled lt 2
         splot 'file.dat' using 1:2:3:(1):(1):(1) with vectors filled
   head lw 2

   sseett cclliipp oonnee and sseett cclliipp ttwwoo affect vectors drawn in 2D.  Please
   see sseett cclliipp and aarrrroowwssttyyllee.



   5522..  XXeerrrroorrbbaarrss


   The xxeerrrroorrbbaarrss style is only relevant to 2D data plots.  xxeerrrroorrbbaarrss
   is like ppooiinnttss, except that a horizontal error bar is also drawn.










   GNUPLOT 4.1                                                       64


   At each point (x,y), a line is drawn from (xlow,y) to (xhigh,y) or
   from (x-xdelta,y) to (x+xdelta,y), depending on how many data col-
   umns are provided.  A tic mark is placed at the ends of the error
   bar (unless sseett bbaarrss is used---see sseett bbaarrss for details).  The basic
   style requires either 3 or 4 columns:

        3 columns:  x  y  xdelta
        4 columns:  x  y  xlow  xhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.




   5533..  XXyyeerrrroorrbbaarrss


   The xxyyeerrrroorrbbaarrss style is only relevant to 2D data plots.  xxyyeerrrroorr--
   bbaarrss is like ppooiinnttss, except that horizontal and vertical error bars
   are also drawn.  At each point (x,y), lines are drawn from (x,y-
   ydelta) to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y) or
   from (x,ylow) to (x,yhigh) and from (xlow,y) to (xhigh,y), depending
   upon the number of data columns provided.  A tic mark is placed at
   the ends of the error bar (unless sseett bbaarrss is used---see sseett bbaarrss
   for details).  Either 4 or 6 input columns are required.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   If data are provided in an unsupported mixed form, the uussiinngg filter
   on the pplloott command should be used to set up the appropriate form.
   For example, if the data are of the form (x,y,xdelta,ylow,yhigh),
   then you can use

         plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars

   An additional input column (5th or 7th) may be used to provide vari-
   able (per-datapoint) color information.




   5544..  YYeerrrroorrbbaarrss


   The yyeerrrroorrbbaarrss (or eerrrroorrbbaarrss) style is only relevant to 2D data
   plots.  yyeerrrroorrbbaarrss is like ppooiinnttss, except that a vertical error bar
   is also drawn.  At each point (x,y), a line is drawn from (x,y-
   ydelta) to (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending on
   how many data columns are provided.  A tic mark is placed at the
   ends of the error bar (unless sseett bbaarrss is used---see sseett bbaarrss for
   details).  Either 3 or 4 input columns are required.










   GNUPLOT 4.1                                                       65


        3 columns:  x  y  ydelta
        4 columns:  x  y  ylow  yhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.

   See also errorbar demo.



   5555..  XXeerrrroorrlliinneess


   The xxeerrrroorrlliinneess style is only relevant to 2D data plots.  xxeerrrroorr--
   lliinneess is like lliinneessppooiinnttss, except that a horizontal error line is
   also drawn. At each point (x,y), a line is drawn from (xlow,y) to
   (xhigh,y) or from (x-xdelta,y) to (x+xdelta,y), depending on how
   many data columns are provided. A tic mark is placed at the ends of
   the error bar (unless sseett bbaarrss is used---see sseett bbaarrss for details).
   The basic style requires either 3 or 4 columns:

        3 columns:  x  y  xdelta
        4 columns:  x  y  xlow  xhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.




   5566..  XXyyeerrrroorrlliinneess


   The xxyyeerrrroorrlliinneess style is only relevant to 2D data plots.  xxyyeerrrroorr--
   lliinneess is like lliinneessppooiinnttss, except that horizontal and vertical error
   bars are also drawn. At each point (x,y), lines are drawn from (x,y-
   ydelta) to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y) or
   from (x,ylow) to (x,yhigh) and from (xlow,y) to (xhigh,y), depending
   upon the number of data columns provided. A tic mark is placed at
   the ends of the error bar (unless sseett bbaarrss is used---see sseett bbaarrss
   for details).  Either 4 or 6 input columns are required.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   If data are provided in an unsupported mixed form, the uussiinngg filter
   on the pplloott command should be used to set up the appropriate form.
   For example, if the data are of the form (x,y,xdelta,ylow,yhigh),
   then you can use

         plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorlines

   An additional input column (5th or 7th) may be used to provide










   GNUPLOT 4.1                                                       66


   variable (per-datapoint) color information.




   5577..  YYeerrrroorrlliinneess


   The yyeerrrroorrlliinneess (or eerrrroorrlliinneess) style is only relevant to 2D data
   plots. yyeerrrroorrlliinneess is like lliinneessppooiinnttss, except that a vertical error
   line is also drawn. At each point (x,y), a line is drawn from (x,y-
   ydelta) to (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending on
   how many data columns are provided. A tic mark is placed at the ends
   of the error bar (see sseett bbaarrss for details).  Either 3 or 4 input
   columns are required.

        3 columns:  x  y  ydelta
        4 columns:  x  y  ylow  yhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.

   See also errorbar demo.



   5588..  33DD ((ssuurrffaaccee)) pplloottss


   Surface plots are generated using the sspplloott command rather than the
   pplloott command. The style wwiitthh lliinneess draws a surface made from a grid
   of lines.  Solid surfaces can be drawn using the style wwiitthh ppmm33dd.
   Usually the surface is displayed at some arbitrary viewing angle,
   such that it clearly represents a 3D surface.  In this case the X,
   Y, and Z axes are all visible in the plot. The illusion of 3D is
   enhanced by choosing hidden line removal or depth-sorted surface
   elements.  See hhiiddddeenn33dd and ppmm33dd ddeepptthhoorrddeerr.  The sspplloott command can
   also calculate and draw contour lines corresponding to constant Z
   values. These contour lines may be drawn onto the surface itself, or
   projected onto the XY plane. See sseett ccoonnttoouurr.








        5588..11..  22DD pprroojjeeccttiioonn ((sseett vviieeww mmaapp))


        An important special case of the sspplloott command is to map the Z
        coordinate onto a 2D surface by projecting the plot along the Z










   GNUPLOT 4.1                                                       67


        axis.  See sseett vviieeww mmaapp.  This plot mode can be used to gener-
        ate contour plots and heat maps.






        5599..  CCoommmmaannddss


        This section lists the commands acceptable to ggnnuupplloott in alpha-
        betical order.  Printed versions of this document contain all
        commands; the text available interactively may not be complete.
        Indeed, on some systems there may be no commands at all listed
        under this heading.

        Note that in most cases unambiguous abbreviations for command
        names and their options are permissible, i.e., "pp ff((xx)) ww llii"
        instead of "pplloott ff((xx)) wwiitthh lliinneess".

        In the syntax descriptions, braces ({}) denote optional argu-
        ments and a vertical bar (|) separates mutually exclusive
        choices.



        6600..  CCdd


        The ccdd command changes the working directory.

        Syntax:
              cd '<directory-name>'

        The directory name must be enclosed in quotes.

        Examples:
              cd 'subdir'
              cd ".."

        It is recommended that Windows users use single-quotes, because
        backslash [\] has special significance inside double-quotes and
        has to be escaped.  For example,
              cd "c:\newdata"
        fails, but
              cd 'c:\newdata'
              cd "c:\\newdata"
        work as expected.














   GNUPLOT 4.1                                                       68


        6611..  CCaallll


        The ccaallll command is identical to the load command with one
        exception: you can have up to ten additional parameters to the
        command (delimited according to the standard parser rules)
        which can be substituted into the lines read from the file.  As
        each line is read from the ccaalllled input file, it is scanned for
        the sequence $$ (dollar-sign) followed by a digit (0--9).  If
        found, the sequence is replaced by the corresponding parameter
        from the ccaallll command line.  If the parameter was specified as
        a string in the ccaallll line, it is substituted without its
        enclosing quotes.  Sequence $$## is replaced by the number of
        passed parameters.  $$ followed by any character will be that
        character; e.g. use $$$$ to get a single $$.  Providing more than
        ten parameters on the ccaallll command line will cause an error.  A
        parameter that was not provided substitutes as nothing.  Files
        being ccaalllled may themselves contain ccaallll or llooaadd commands.

        Syntax:
              call "<input-file>" <parameter-0> <parm-1> ... <parm-9>

        The name of the input file must be enclosed in quotes, and it
        is recommended that parameters are similarly enclosed in quotes
        (future versions of gnuplot may treat quoted and unquoted argu-
        ments differently).

        Example:

        If the file 'calltest.gp' contains the line:
              print "argc=$# p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6
        p7=x$7x"

        entering the command:
              call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"

        will display:
              argc=7 p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2
        p7=xx

        NOTE: there is a clash in syntax with the datafile uussiinngg call-
        back operator.  Use $$$$nn or ccoolluummnn((nn)) to access column n from a
        datafile inside a ccaalllled datafile plot.



        6622..  CClleeaarr


        The cclleeaarr command erases the current screen or output device as
        specified by sseett oouuttppuutt.  This usually generates a formfeed on
        hardcopy devices.  Use sseett tteerrmmiinnaall to set the device type.











   GNUPLOT 4.1                                                       69


        For some terminals cclleeaarr erases only the portion of the plot-
        ting surface defined by sseett ssiizzee, so for these it can be used
        in conjunction with sseett mmuullttiipplloott to create an inset.

        Example:
              set multiplot
              plot sin(x)
              set origin 0.5,0.5
              set size 0.4,0.4
              clear
              plot cos(x)
              unset multiplot

        Please see sseett mmuullttiipplloott, sseett ssiizzee, and sseett oorriiggiinn for details
        of these commands.



        6633..  DDoo


        Syntax:
              do for <iteration-spec> {
                   <commands>
                   <commands>
              }
        Execute a sequence of commands multiple times.  The commands
        must be enclosed in curly brackets, and the opening "{" must be
        on the same line as the ddoo keyword.  This command cannot be
        used with old-style (un-bracketed) if/else statements.  See iiff.
        For examples of iteration specifiers, see iitteerraattiioonn.  Example:
              set multiplot layout 2,2
              do for [name in "A B C D"] {
                  filename = name . ".dat"
                  set title sprintf("Condition %s",name)
                  plot filename title name
              }
              unset multiplot



        6644..  EEvvaalluuaattee


        The eevvaalluuaattee command executes the commands given as an argument
        string.  Newline characters are not allowed within the string.

        Syntax:
              eval <string expression>

        This is especially useful for a repetition of similar commands.

        Example:










   GNUPLOT 4.1                                                       70


              set_label(x, y, text) \
                = sprintf("set label '%s' at %f, %f point pt 5", text,
        x, y)
              eval set_label(1., 1., 'one/one')
              eval set_label(2., 1., 'two/one')
              eval set_label(1., 2., 'one/two')

        Please see ssuubbssttiittuuttiioonn mmaaccrrooss for another way to execute com-
        mands from a string.



        6655..  EExxiitt


        The commands eexxiitt and qquuiitt, as well as the END-OF-FILE charac-
        ter (usually Ctrl-D) terminate input from the current input
        stream: terminal session, pipe, and file input (pipe).

        If input streams are nested (inherited llooaadd scripts), then
        reading will continue in the parent stream. When the top level
        stream is closed, the program itself will exit.

        The command eexxiitt ggnnuupplloott will immediately and unconditionally
        cause gnuplot to exit even if the input stream is multiply
        nested.  In this case any open output files may not be com-
        pleted cleanly. Example of use:

              bind "ctrl-x" "unset output; exit gnuplot"

        See help for bbaattcchh//iinntteerraaccttiivvee for more details.



        6666..  FFiitt


        The ffiitt command can fit a user-supplied expression to a set of
        data points (x,z) or (x,y,z), using an implementation of the
        nonlinear least-squares (NLLS) Marquardt-Levenberg algorithm.
        Any user-defined variable occurring in the expression may serve
        as a fit parameter, but the return type of the expression must
        be real.

        Syntax:
              fit {<ranges>} <expression>
                  '<datafile>' {datafile-modifiers}
                  via '<parameter file>' | <var1>{,<var2>,...}

        Ranges may be specified to temporarily limit the data which is
        to be fitted; any out-of-range data points are ignored. The
        syntax is
              [{dummy_variable=}{<min>}{:<max>}],










   GNUPLOT 4.1                                                       71


        analogous to pplloott; see pplloott rraannggeess.

        <expression> is any valid ggnnuupplloott expression, although it is
        usual to use a previously user-defined function of the form
        f(x) or f(x,y).

        <datafile> is treated as in the pplloott command.  All the pplloott
        ddaattaaffiillee modifiers (uussiinngg, eevveerryy,...) except ssmmooootthh and the
        deprecated tthhrruu are applicable to ffiitt. See pplloott ddaattaaffiillee.

        The default data formats for fitting functions with a single
        independent variable, z=f(x), are z or x:z.  That is, if there
        is only a single column then it is the dependent variable and
        the line numbers is the independent variable.  If there are two
        columns, the first is the independent variable and the second
        is the dependent variable.

        Those formats can be changed with the datafile uussiinngg qualifier,
        for example to take the z value from a different column or to
        calculate it from several columns.  A third uussiinngg qualifier (a
        column number or an expression), if present, is interpreted as
        the standard deviation of the corresponding z value and is used
        to compute a weight for the datum, 1/s**2.  Otherwise, all data
        points are weighted equally, with a weight of one. Note that if
        you don't specify a uussiinngg option at all, no z standard devia-
        tions are read from the datafile even if it does have a third
        column, so you'll always get unit weights.

        To fit a function with two independent variables, z=f(x,y), the
        required format is uussiinngg with four items, x:y:z:s.  The com-
        plete format must be given---no default columns are assumed for
        a missing token.  Weights for each data point are evaluated
        from 's' as above.  If error estimates are not available, a
        constant value can be specified as a constant expression (see
        pplloott ddaattaaffiillee uussiinngg), e.g., uussiinngg 11::22::33::((11)).

        The fit function may have up to five independent variables.
        There must be two more uussiinngg qualifiers than there are indepen-
        dent variables, unless there is only one variable.  The allowed
        formats, and the default dummy variable names, are as follows:

              z
              x:z
              x:z:s
              x:y:z:s
              x:y:t:z:s
              x:y:t:u:z:s
              x:y:t:u:v:z:s

        The dummy variable names may be changed with ranges as noted
        above.  The first range corresponds to the first uussiinngg spec,
        etc.  A range may also be given for z (the dependent variable),
        but that name cannot be changed.










   GNUPLOT 4.1                                                       72


        Multiple datasets may be simultaneously fit with functions of
        one independent variable by making y a 'pseudo-variable', e.g.,
        the dataline number, and fitting as two independent variables.
        See ffiitt mmuullttii--bbrraanncchh.

        The vviiaa qualifier specifies which parameters are to be
        adjusted, either directly, or by referencing a parameter file.

        Examples:
              f(x) = a*x**2 + b*x + c
              g(x,y) = a*x**2 + b*y**2 + c*x*y
              FIT_LIMIT = 1e-6
              fit f(x) 'measured.dat' via 'start.par'
              fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
              fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
              fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c
              fit a0 + a1*x/(1 + a2*x/(1 + a3*x)) 'measured.dat' via
        a0,a1,a2,a3
              fit a*x + b*y 'surface.dat' using 1:2:3:(1) via a,b
              fit [*:*][yaks=*:*] a*x+b*yaks 'surface.dat' u 1:2:3:(1)
        via a,b
              fit a*x + b*y + c*t 'foo.dat' using 1:2:3:4:(1) via a,b,c
              h(x,y,t,u,v) = a*x + b*y + c*t + d*u + e*v
              fit h(x,y,t,u,v) 'foo.dat' using 1:2:3:4:5:6:(1) via
        a,b,c,d,e

        After each iteration step, detailed information about the cur-
        rent state of the fit is written to the display.  The same
        information about the initial and final states is written to a
        log file, "fit.log".  This file is always appended to, so as to
        not lose any previous fit history;  it should be deleted or
        renamed as desired. By using the command sseett ffiitt llooggffiillee, the
        name of the log file can be changed.

        If gnuplot was built with this option, and you activated it
        using sseett ffiitt eerrrroorrvvaarriiaabblleess, the error for each fitted parame-
        ter will be stored in a variable named like the parameter, but
        with "_err" appended.  Thus the errors can be used as input for
        further computations.

        The fit may be interrupted by pressing Ctrl-C.  After the cur-
        rent iteration completes, you have the option to (1) stop the
        fit and accept the current parameter values, (2) continue the
        fit, (3) execute a ggnnuupplloott command as specified by the environ-
        ment variable FIT_SCRIPT.  The default for FIT_SCRIPT is
        rreepplloott, so if you had previously plotted both the data and the
        fitting function in one graph, you can display the current
        state of the fit.

        Once ffiitt has finished, the uuppddaattee command may be used to store
        final values in a file for subsequent use as a parameter file.
        See uuppddaattee for details.











   GNUPLOT 4.1                                                       73


             6666..11..  AAddjjuussttaabbllee ppaarraammeetteerrss


             There are two ways that vviiaa can specify the parameters to
             be adjusted, either directly on the command line or indi-
             rectly, by referencing a parameter file.  The two use dif-
             ferent means to set initial values.

             Adjustable parameters can be specified by a comma-sepa-
             rated list of variable names after the vviiaa keyword.  Any
             variable that is not already defined is created with an
             initial value of 1.0.  However, the fit is more likely to
             converge rapidly if the variables have been previously
             declared with more appropriate starting values.

             In a parameter file, each parameter to be varied and a
             corresponding initial value are specified, one per line,
             in the form
                   varname = value

             Comments, marked by '#', and blank lines are permissible.
             The special form
                   varname = value       # FIXED

             means that the variable is treated as a 'fixed parameter',
             initialized by the parameter file, but not adjusted by
             ffiitt.  For clarity, it may be useful to designate variables
             as fixed parameters so that their values are reported by
             ffiitt.  The keyword ## FFIIXXEEDD has to appear in exactly this
             form.




             6666..22..  SShhoorrtt iinnttrroodduuccttiioonn


             ffiitt is used to find a set of parameters that 'best' fits
             your data to your user-defined function.  The fit is
             judged on the basis of the sum of the squared differences
             or 'residuals' (SSR) between the input data points and the
             function values, evaluated at the same places.  This quan-
             tity is often called 'chisquare' (i.e., the Greek letter
             chi, to the power of 2).  The algorithm attempts to mini-
             mize SSR, or more precisely, WSSR, as the residuals are
             'weighted' by the input data errors (or 1.0) before being
             squared; see ffiitt eerrrroorr__eessttiimmaatteess for details.

             That's why it is called 'least-squares fitting'.  Let's
             look at an example to see what is meant by 'non-linear',
             but first we had better go over some terms.  Here it is
             convenient to use z as the dependent variable for user-
             defined functions of either one independent variable,










   GNUPLOT 4.1                                                       74


             z=f(x), or two independent variables, z=f(x,y).  A parame-
             ter is a user-defined variable that ffiitt will adjust, i.e.,
             an unknown quantity in the function declaration.  Linear-
             ity/non-linearity refers to the relationship of the depen-
             dent variable, z, to the parameters which ffiitt is adjust-
             ing, not of z to the independent variables, x and/or y.
             (To be technical, the second {and higher} derivatives of
             the fitting function with respect to the parameters are
             zero for a linear least-squares problem).

             For linear least-squares (LLS), the user-defined function
             will be a sum of simple functions, not involving any
             parameters, each multiplied by one parameter.  NLLS han-
             dles more complicated functions in which parameters can be
             used in a large number of ways.  An example that illus-
             trates the difference between linear and nonlinear least-
             squares is the Fourier series.  One member may be written
             as
                  z=a*sin(c*x) + b*cos(c*x).
             If a and b are the unknown parameters and c is constant,
             then estimating values of the parameters is a linear
             least-squares problem.  However, if c is an unknown param-
             eter, the problem is nonlinear.

             In the linear case, parameter values can be determined by
             comparatively simple linear algebra, in one direct step.
             However LLS is a special case which is also solved along
             with more general NLLS problems by the iterative procedure
             that ggnnuupplloott uses.  ffiitt attempts to find the minimum by
             doing a search.  Each step (iteration) calculates WSSR
             with a new set of parameter values.  The Marquardt-Leven-
             berg algorithm selects the parameter values for the next
             iteration.  The process continues until a preset criterion
             is met, either (1) the fit has "converged" (the relative
             change in WSSR is less than FIT_LIMIT), or (2) it reaches
             a preset iteration count limit, FIT_MAXITER (see ffiitt ccoonn--
             ttrrooll vvaarriiaabblleess).  The fit may also be interrupted and sub-
             sequently halted from the keyboard (see ffiitt).  The user
             variable FIT_CONVERGED contains 1 if the previous fit com-
             mand terminated due to convergence; it contains 0 if the
             previous fit terminated for any other reason.

             Often the function to be fitted will be based on a model
             (or theory) that attempts to describe or predict the be-
             haviour of the data.  Then ffiitt can be used to find values
             for the free parameters of the model, to determine how
             well the data fits the model, and to estimate an error
             range for each parameter.  See ffiitt eerrrroorr__eessttiimmaatteess.

             Alternatively, in curve-fitting, functions are selected
             independent of a model (on the basis of experience as to
             which are likely to describe the trend of the data with
             the desired resolution and a minimum number of










   GNUPLOT 4.1                                                       75


             parameters*functions.)  The ffiitt solution then provides an
             analytic representation of the curve.

             However, if all you really want is a smooth curve through
             your data points, the ssmmooootthh option to pplloott may be what
             you've been looking for rather than ffiitt.



             6666..33..  EErrrroorr eessttiimmaatteess


             In ffiitt, the term "error" is used in two different con-
             texts, data error estimates and parameter error estimates.

             Data error estimates are used to calculate the relative
             weight of each data point when determining the weighted
             sum of squared residuals, WSSR or chisquare.  They can
             affect the parameter estimates, since they determine how
             much influence the deviation of each data point from the
             fitted function has on the final values.  Some of the ffiitt
             output information, including the parameter error esti-
             mates, is more meaningful if accurate data error estimates
             have been provided.

             The 'statistical overview' describes some of the ffiitt out-
             put and gives some background for the 'practical guide-
             lines'.




                  6666..33..11..  SSttaattiissttiiccaall oovveerrvviieeww


                  The theory of non-linear least-squares (NLLS) is gen-
                  erally described in terms of a normal distribution of
                  errors, that is, the input data is assumed to be a
                  sample from a population having a given mean and a
                  Gaussian (normal) distribution about the mean with a
                  given standard deviation.  For a sample of suffi-
                  ciently large size, and knowing the population stan-
                  dard deviation, one can use the statistics of the
                  chisquare distribution to describe a "goodness of
                  fit" by looking at the variable often called
                  "chisquare".  Here, it is sufficient to say that a
                  reduced chisquare (chisquare/degrees of freedom,
                  where degrees of freedom is the number of datapoints
                  less the number of parameters being fitted) of 1.0 is
                  an indication that the weighted sum of squared devia-
                  tions between the fitted function and the data points
                  is the same as that expected for a random sample from
                  a population characterized by the function with the










   GNUPLOT 4.1                                                       76


                  current value of the parameters and the given stan-
                  dard deviations.

                  If the standard deviation for the population is not
                  constant, as in counting statistics where variance =
                  counts, then each point should be individually
                  weighted when comparing the observed sum of devia-
                  tions and the expected sum of deviations.

                  At the conclusion ffiitt reports 'stdfit', the standard
                  deviation of the fit, which is the rms of the residu-
                  als, and the variance of the residuals, also called
                  'reduced chisquare' when the data points are
                  weighted.  The number of degrees of freedom (the num-
                  ber of data points minus the number of fitted parame-
                  ters) is used in these estimates because the parame-
                  ters used in calculating the residuals of the data-
                  points were obtained from the same data.  These val-
                  ues are exported to the variables
                        FIT_NDF = Number of degrees of freedom
                        FIT_WSSR = Weighted sum-of-squares residual
                        FIT_STDFIT = sqrt(WSSR/NDF)

                  To estimate confidence levels for the parameters, one
                  can use the minimum chisquare obtained from the fit
                  and chisquare statistics to determine the value of
                  chisquare corresponding to the desired confidence
                  level, but considerably more calculation is required
                  to determine the combinations of parameters which
                  produce such values.

                  Rather than determine confidence intervals, ffiitt
                  reports parameter error estimates which are readily
                  obtained from the variance-covariance matrix after
                  the final iteration.  By convention, these estimates
                  are called "standard errors" or "asymptotic standard
                  errors", since they are calculated in the same way as
                  the standard errors (standard deviation of each
                  parameter) of a linear least-squares problem, even
                  though the statistical conditions for designating the
                  quantity calculated to be a standard deviation are
                  not generally valid for the NLLS problem.  The asymp-
                  totic standard errors are generally over-optimistic
                  and should not be used for determining confidence
                  levels, but are useful for qualitative purposes.

                  The final solution also produces a correlation matrix
                  indicating correlation of parameters in the region of
                  the solution; The main diagonal elements, autocorre-
                  lation, are always 1; if all parameters were indepen-
                  dent, the off-diagonal elements would be nearly 0.
                  Two variables which completely compensate each other
                  would have an off-diagonal element of unit magnitude,










   GNUPLOT 4.1                                                       77


                  with a sign depending on whether the relation is pro-
                  portional or inversely proportional.  The smaller the
                  magnitudes of the off-diagonal elements, the closer
                  the estimates of the standard deviation of each
                  parameter would be to the asymptotic standard error.



                  6666..33..22..  PPrraaccttiiccaall gguuiiddeelliinneess


                  If you have a basis for assigning weights to each
                  data point, doing so lets you make use of additional
                  knowledge about your measurements, e.g., take into
                  account that some points may be more reliable than
                  others.  That may affect the final values of the
                  parameters.

                  Weighting the data provides a basis for interpreting
                  the additional ffiitt output after the last iteration.
                  Even if you weight each point equally, estimating an
                  average standard deviation rather than using a weight
                  of 1 makes WSSR a dimensionless variable, as
                  chisquare is by definition.

                  Each fit iteration will display information which can
                  be used to evaluate the progress of the fit.  (An '*'
                  indicates that it did not find a smaller WSSR and is
                  trying again.)  The 'sum of squares of residuals',
                  also called 'chisquare', is the WSSR between the data
                  and your fitted function; ffiitt has minimized that.  At
                  this stage, with weighted data, chisquare is expected
                  to approach the number of degrees of freedom (data
                  points minus parameters).  The WSSR can be used to
                  calculate the reduced chisquare (WSSR/ndf) or stdfit,
                  the standard deviation of the fit, sqrt(WSSR/ndf).
                  Both of these are reported for the final WSSR.

                  If the data are unweighted, stdfit is the rms value
                  of the deviation of the data from the fitted func-
                  tion, in user units.

                  If you supplied valid data errors, the number of data
                  points is large enough, and the model is correct, the
                  reduced chisquare should be about unity.  (For
                  details, look up the 'chi-squared distribution' in
                  your favourite statistics reference.)  If so, there
                  are additional tests, beyond the scope of this over-
                  view, for determining how well the model fits the
                  data.

                  A reduced chisquare much larger than 1.0 may be due
                  to incorrect data error estimates, data errors not










   GNUPLOT 4.1                                                       78


                  normally distributed, systematic measurement errors,
                  'outliers', or an incorrect model function.  A plot
                  of the residuals, e.g., pplloott ''ddaattaaffiillee'' uussiinngg
                  11::(($$22--ff(($$11)))), may help to show any systematic trends.
                  Plotting both the data points and the function may
                  help to suggest another model.

                  Similarly, a reduced chisquare less than 1.0 indi-
                  cates WSSR is less than that expected for a random
                  sample from the function with normally distributed
                  errors.  The data error estimates may be too large,
                  the statistical assumptions may not be justified, or
                  the model function may be too general, fitting fluc-
                  tuations in a particular sample in addition to the
                  underlying trends.  In the latter case, a simpler
                  function may be more appropriate.

                  You'll have to get used to both ffiitt and the kind of
                  problems you apply it to before you can relate the
                  standard errors to some more practical estimates of
                  parameter uncertainties or evaluate the significance
                  of the correlation matrix.

                  Note that ffiitt, in common with most NLLS implementa-
                  tions, minimizes the weighted sum of squared dis-
                  tances (y-f(x))**2.  It does not provide any means to
                  account for "errors" in the values of x, only in y.
                  Also, any "outliers" (data points outside the normal
                  distribution of the model) will have an exaggerated
                  effect on the solution.



             6666..44..  CCoonnttrrooll


             There are a number of ggnnuupplloott variables that can be
             defined to affect ffiitt.  Those which can be defined once
             ggnnuupplloott is running are listed under 'control_variables'
             while those defined before starting ggnnuupplloott are listed
             under 'environment_variables'.




                  6666..44..11..  CCoonnttrrooll vvaarriiaabblleess


                  The default epsilon limit (1e-5) may be changed by
                  declaring a value for
                        FIT_LIMIT
                  When the sum of squared residuals changes between two
                  iteration steps by a factor less than this number










   GNUPLOT 4.1                                                       79


                  (epsilon), the fit is considered to have 'converged'.

                  The maximum number of iterations may be limited by
                  declaring a value for
                        FIT_MAXITER
                  A value of 0 (or not defining it at all)  means that
                  there is no limit.

                  If you need even more control about the algorithm,
                  and know the Marquardt-Levenberg algorithm well,
                  there are some more variables to influence it. The
                  startup value of llaammbbddaa is normally calculated auto-
                  matically from the ML-matrix, but if you want to, you
                  may provide your own one with
                        FIT_START_LAMBDA
                  Specifying FIT_START_LAMBDA as zero or less will re-
                  enable the automatic selection. The variable
                        FIT_LAMBDA_FACTOR
                  gives the factor by which llaammbbddaa is increased or
                  decreased whenever the chi-squared target function
                  increased or decreased significantly.  Setting
                  FIT_LAMBDA_FACTOR to zero re-enables the default fac-
                  tor of 10.0.

                  Other variables with the FIT_ prefix may be added to
                  ffiitt, so it is safer not to use that prefix for user-
                  defined variables.

                  The variables FIT_SKIP and FIT_INDEX were used by
                  earlier releases of ggnnuupplloott with a 'fit' patch called
                  ggnnuuffiitt and are no longer available.  The datafile
                  eevveerryy modifier provides the functionality of
                  FIT_SKIP.  FIT_INDEX was used for multi-branch fit-
                  ting, but multi-branch fitting of one independent
                  variable is now done as a pseudo-3D fit in which the
                  second independent variable and uussiinngg are used to
                  specify the branch.  See ffiitt mmuullttii--bbrraanncchh.



                  6666..44..22..  EEnnvviirroonnmmeenntt vvaarriiaabblleess


                  The environment variables must be defined before ggnnuu--
                  pplloott is executed; how to do so depends on your oper-
                  ating system.

                        FIT_LOG
                  changes the name (and/or path) of the file to which
                  the fit log will be written from the default of
                  "fit.log" in the working directory. The default value
                  can be overwritten using the command sseett ffiitt llooggffiillee.











   GNUPLOT 4.1                                                       80


                        FIT_SCRIPT
                  specifies a command that may be executed after an
                  user interrupt. The default is rreepplloott, but a pplloott or
                  llooaadd command may be useful to display a plot cus-
                  tomized to highlight the progress of the fit.



             6666..55..  MMuullttii--bbrraanncchh


             In multi-branch fitting, multiple data sets can be simul-
             taneously fit with functions of one independent variable
             having common parameters by minimizing the total WSSR.
             The function and parameters (branch) for each data set are
             selected by using a 'pseudo-variable', e.g., either the
             dataline number (a 'column' index of -1) or the datafile
             index (-2), as the second independent variable.

             Example:  Given two exponential decays of the form,
             z=f(x), each describing a different data set but having a
             common decay time, estimate the values of the parameters.
             If the datafile has the format x:z:s, then
                  f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
                  fit f(x,y) 'datafile' using  1:-2:2:3  via a, b, tau

             For a more complicated example, see the file "hexa.fnc"
             used by the "fit.dem" demo.

             Appropriate weighting may be required since unit weights
             may cause one branch to predominate if there is a differ-
             ence in the scale of the dependent variable.  Fitting each
             branch separately, using the multi-branch solution as ini-
             tial values, may give an indication as to the relative
             effect of each branch on the joint solution.



             6666..66..  SSttaarrttiinngg vvaalluueess


             Nonlinear fitting is not guaranteed to converge to the
             global optimum (the solution with the smallest sum of
             squared residuals, SSR), and can get stuck at a local min-
             imum.  The routine has no way to determine that;  it is up
             to you to judge whether this has happened.

             ffiitt may, and often will get "lost" if started far from a
             solution, where SSR is large and changing slowly as the
             parameters are varied, or it may reach a numerically
             unstable region (e.g., too large a number causing a float-
             ing point overflow) which results in an "undefined value"
             message or ggnnuupplloott halting.










   GNUPLOT 4.1                                                       81


             To improve the chances of finding the global optimum, you
             should set the starting values at least roughly in the
             vicinity of the solution, e.g., within an order of magni-
             tude, if possible.  The closer your starting values are to
             the solution, the less chance of stopping at another mini-
             mum.  One way to find starting values is to plot data and
             the fitting function on the same graph and change parame-
             ter values and rreepplloott until reasonable similarity is
             reached.  The same plot is also useful to check whether
             the fit stopped at a minimum with a poor fit.

             Of course, a reasonably good fit is not proof there is not
             a "better" fit (in either a statistical sense, character-
             ized by an improved goodness-of-fit criterion, or a physi-
             cal sense, with a solution more consistent with the
             model.)  Depending on the problem, it may be desirable to
             ffiitt with various sets of starting values, covering a rea-
             sonable range for each parameter.



             6666..77..  TTiippss


             Here are some tips to keep in mind to get the most out of
             ffiitt.  They're not very organized, so you'll have to read
             them several times until their essence has sunk in.

             The two forms of the vviiaa argument to ffiitt serve two largely
             distinct purposes.  The vviiaa ""ffiillee"" form is best used for
             (possibly unattended) batch operation, where you just sup-
             ply the startup values in a file and can later use uuppddaattee
             to copy the results back into another (or the same) param-
             eter file.

             The vviiaa vvaarr11,, vvaarr22,, ...... form is best used interactively,
             where the command history mechanism may be used to edit
             the list of parameters to be fitted or to supply new
             startup values for the next try.  This is particularly
             useful for hard problems, where a direct fit to all param-
             eters at once won't work without good starting values.  To
             find such, you can iterate several times, fitting only
             some of the parameters, until the values are close enough
             to the goal that the final fit to all parameters at once
             will work.

             Make sure that there is no mutual dependency among parame-
             ters of the function you are fitting.  For example, don't
             try to fit a*exp(x+b), because a*exp(x+b)=a*exp(b)*exp(x).
             Instead, fit either a*exp(x) or exp(x+b).

             A technical issue:  the parameters must not be too differ-
             ent in magnitude.  The larger the ratio of the largest and










   GNUPLOT 4.1                                                       82


             the smallest absolute parameter values, the slower the fit
             will converge.  If the ratio is close to or above the
             inverse of the machine floating point precision, it may
             take next to forever to converge, or refuse to converge at
             all.  You will have to adapt your function to avoid this,
             e.g., replace 'parameter' by '1e9*parameter' in the func-
             tion definition, and divide the starting value by 1e9.

             If you can write your function as a linear combination of
             simple functions weighted by the parameters to be fitted,
             by all means do so.  That helps a lot, because the problem
             is no longer nonlinear and should converge with only a
             small number of iterations, perhaps just one.

             Some prescriptions for analysing data, given in practical
             experimentation courses, may have you first fit some func-
             tions to your data, perhaps in a multi-step process of
             accounting for several aspects of the underlying theory
             one by one, and then extract the information you really
             wanted from the fitting parameters of those functions.
             With ffiitt, this may often be done in one step by writing
             the model function directly in terms of the desired param-
             eters.  Transforming data can also quite often be avoided,
             though sometimes at the cost of a more difficult fit prob-
             lem.  If you think this contradicts the previous paragraph
             about simplifying the fit function, you are correct.

             A "singular matrix" message indicates that this implemen-
             tation of the Marquardt-Levenberg algorithm can't calcu-
             late parameter values for the next iteration.  Try differ-
             ent starting values, writing the function in another form,
             or a simpler function.

             Finally, a nice quote from the manual of another fitting
             package (fudgit), that kind of summarizes all these
             issues:  "Nonlinear fitting is an art!"



        6677..  HHeellpp


        The hheellpp command displays built-in help. To specify information
        on a particular topic use the syntax:

              help {<topic>}

        If <topic> is not specified, a short message is printed about
        ggnnuupplloott.  After help for the requested topic is given, a menu
        of subtopics is given; help for a subtopic may be requested by
        typing its name, extending the help request.  After that
        subtopic has been printed, the request may be extended again or
        you may go back one level to the previous topic.  Eventually,










   GNUPLOT 4.1                                                       83


        the ggnnuupplloott command line will return.

        If a question mark (?) is given as the topic, the list of top-
        ics currently available is printed on the screen.



        6688..  HHiissttoorryy


        hhiissttoorryy command lists or saves previous entries in the history
        of the command line editing, or executes an entry.

        Here you find 'usage by examples':

              history               # show the complete history
              history 5             # show last 5 entries in the his-
        tory
              history quiet 5       # show last 5 entries without entry
        numbers
              history "hist.gp"     # write the complete history to
        file hist.gp
              history "hist.gp" append # append the complete history to
        file hist.gp
              history 10 "hist.gp"  # write last 10 commands to file
        hist.gp
              history 10 "|head -5 >>diary.gp" # write 5 history com-
        mands using pipe
              history ?load         # show all history entries starting
        with "load"
              history ?"set c"      # like above, several words
        enclosed in quotes
              hi !reread            # execute last entry starting with
        "reread"
              hist !"set xr"        # like above, several words
        enclosed in quotes
              hi !hi                # guess yourself :-))

        On systems which support a popen function (Unix), the output of
        history can be piped through an external program by starting
        the file name with a '|', as one of the above examples demon-
        strates.



        6699..  IIff


        New syntax:
              if (<condition>) { <command>; <command>
                     <commands>
                     <commands>
              } else {










   GNUPLOT 4.1                                                       84


                     <commands>
              }
        Old syntax:
              if (<condition>) <command-line> [; else if (<condition>)
        ...; else ...]

        This version of gnuplot supports block-structured if/else
        statements. If the keyword iiff or eellssee is immediately followed
        by an opening "{", then conditional execution applies to all
        statements, possibly on multiple input lines, until a matching
        "}" terminates the block.  If commands may be nested.

        The old single-line if/else syntax is still supported, but can
        not be mixed with the new block-structured syntax.  See iiff--oolldd.




             6699..11..  IIff--oolldd


             Through gnuplot version 4.4, the scope of the if/else com-
             mands was limited to a single input line. This has been
             replaced by allowing a multi-line clause to be enclosed in
             curly brackets. The old syntax is still honored by itself
             but cannot be used inside a bracketed clause.

             If no opening "{" follows the iiff keyword, the command(s)
             in <command-line> will be executed if <condition> is true
             (non-zero) or skipped if <condition> is false (zero).
             Either case will consume commands on the input line until
             the end of the line or an occurrence of eellssee.  Note that
             use of ;; to allow multiple commands on the same line will
             _not_ end the conditionalized commands.

             Examples:
                   pi=3
                   if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1);
             print pi
             will display:
                   ?Fixing pi!
                   3.14159265358979
             but
                   if (1==2) print "Never see this"; print "Or this
             either"
             will not display anything.

             else:
                   v=0
                   v=v+1; if (v%2) print "2" ; else if (v%3) print "3";
             else print "fred"
             (repeat the last line repeatedly!)











   GNUPLOT 4.1                                                       85


             See rreerreeaadd for an example of using if and reread together
             to perform a loop.



        7700..  IItteerraattiioonn


        The pplloott, sspplloott, sseett and uunnsseett commands may optionally contain
        an iteration clause.  This has the effect of executing the
        basic command multiple times, each time re-evaluating any
        expressions that make use of the iteration control variable.
        Iteration of arbitrary command sequences can be requested using
        the ddoo command.  Two forms of iteration clause are currently
        supported:

              for [intvar = start:end{:increment}]
              for [stringvar in "A B C D"]

        Examples:

              plot for [filename in "A.dat B.dat C.dat"] filename using
        1:2 with lines
              plot for [basename in "A B C"] basename.".dat" using 1:2
        with lines
              set for [i = 1:10] style line i lc rgb "blue"
              unset for [tag = 100:200] label tag

        Nested iteration is supported:

              set for [i=1:9] for [j=1:9] label i*10+j
        sprintf("%d",i*10+j) at i,j

        See additional documentation for pplloott iitteerraattiioonn, ddoo.




        7711..  LLooaadd


        The llooaadd command executes each line of the specified input file
        as if it had been typed in interactively.  Files created by the
        ssaavvee command can later be llooaadded.  Any text file containing
        valid commands can be created and then executed by the llooaadd
        command.  Files being llooaadded may themselves contain llooaadd or
        ccaallll commands.  See ccoommmmeennttss for information about comments in
        commands.  To llooaadd with arguments, see ccaallll.

        Syntax:
              load "<input-file>"

        The name of the input file must be enclosed in quotes.










   GNUPLOT 4.1                                                       86


        The special filename "-" may be used to llooaadd commands from
        standard input.  This allows a ggnnuupplloott command file to accept
        some commands from standard input.  Please see help for
        bbaattcchh//iinntteerraaccttiivvee for more details.

        On some systems which support a popen function (Unix), the load
        file can be read from a pipe by starting the file name with a
        '<'.

        Examples:
              load 'work.gnu'
              load "func.dat"
              load "< loadfile_generator.sh"

        The llooaadd command is performed implicitly on any file names
        given as arguments to ggnnuupplloott.  These are loaded in the order
        specified, and then ggnnuupplloott exits.



        7722..  LLoowweerr


        Syntax:
              lower {plot_window_nb}

        The lloowweerr command lowers (opposite to rraaiissee) plot window(s)
        associated with the interactive terminal of your gnuplot ses-
        sion, i.e. ppmm, wwiinn, wwxxtt or xx1111. It puts the plot window to bot-
        tom in the z-order windows stack of the window manager of your
        desktop.

        As xx1111 and wwxxtt support multiple plot windows, then by default
        they lower these windows in descending order of most recently
        created on top to the least recently created on bottom. If a
        plot number is supplied as an optional parameter, only the
        associated plot window will be lowered if it exists.

        The optional parameter is ignored for single plot-window termi-
        nals, i.e. ppmm and wwiinn.



        7733..  PPaauussee


        The ppaauussee command displays any text associated with the command
        and then waits a specified amount of time or until the carriage
        return is pressed.  ppaauussee is especially useful in conjunction
        with llooaadd files.

        Syntax:
              pause <time> {"<string>"}










   GNUPLOT 4.1                                                       87


              pause mouse {<endcondition>}{, <endcondition>}
        {"<string>"}

        <time> may be any constant or expression.  Choosing -1 will
        wait until a carriage return is hit, zero (0) won't pause at
        all, and a positive number will wait the specified number of
        seconds.  The time is rounded to an integer number of seconds
        if subsecond time resolution is not supported by the given
        platform.  ppaauussee 00 is synonymous with pprriinntt.

        If the current terminal supports mmoouussiinngg, then ppaauussee mmoouussee will
        terminate on either a mouse click or on ctrl-C.  For all other
        terminals, or if mousing is not active, ppaauussee mmoouussee is equiva-
        lent to ppaauussee --11.

        If one or more end conditions are given after ppaauussee mmoouussee, then
        any one of the conditions will terminate the pause. The possi-
        ble end conditions are kkeeyypprreessss, bbuuttttoonn11, bbuuttttoonn22, bbuuttttoonn33,
        cclloossee, and aannyy.  If the pause terminates on a keypress, then
        the ascii value of the key pressed is returned in MOUSE_KEY.
        The character itself is returned as a one character string in
        MOUSE_CHAR. Hotkeys (bind command) are disabled if keypress is
        one of the end conditions.  Zooming is disabled if button3 is
        one of the end conditions.

        In all cases the coordinates of the mouse are returned in vari-
        ables MOUSE_X, MOUSE_Y, MOUSE_X2, MOUSE_Y2.  See mmoouussee vvaarrii--
        aabblleess.

        Note: Since ppaauussee communicates with the operating system rather
        than the graphics, it may behave differently with different
        device drivers (depending upon how text and graphics are
        mixed).

        Examples:
              pause -1    # Wait until a carriage return is hit
              pause 3     # Wait three seconds
              pause -1  "Hit return to continue"
              pause 10  "Isn't this pretty?  It's a cubic spline."
              pause mouse "Click any mouse button on selected data
        point"
              pause mouse keypress "Type a letter from A-F in the
        active window"
              pause mouse button1,keypress
              pause mouse any "Any key or button will terminate"

        The variant "pause mouse key" will resume after any keypress in
        the active plot window. If you want to wait for a particular
        key to be pressed, you can use a reread loop such as:

              print "I will resume after you hit the Tab key in the
        plot window"
              load "wait_for_tab"










   GNUPLOT 4.1                                                       88


        File "wait_for_tab" contains the lines

              pause mouse key
              if (MOUSE_KEY != 9) reread




        7744..  PPlloott


        pplloott is the primary command for drawing plots with ggnnuupplloott.  It
        creates plots of functions and data in many, many ways.  pplloott
        is used to draw 2D functions and data; sspplloott draws 2D projec-
        tions of 3D surfaces and data.  pplloott and sspplloott offer many fea-
        tures in common; see sspplloott for differences.  Note specifically
        that although the bbiinnaarryy <<bbiinnaarryy lliisstt>> variation does work for
        both pplloott and sspplloott, there are small differences between them.

        Syntax:
              plot {<ranges>}
                   {<iteration>}
                   {<function> | {"<datafile>" {datafile-modifiers}}}
                   {axes <axes>} {<title-spec>} {with <style>}
                   {, {definitions{,}} <function> ...}

        where either a <function> or the name of a data file enclosed
        in quotes is supplied.  A function is a mathematical expression
        or a pair of mathematical expressions in parametric mode.
        Functions may be builtin, user-defined, or provided in the plot
        command itself.  Multiple datafiles and/or functions may be
        plotted in a single command, separated by commas.  See ddaattaa,
        ffuunnccttiioonnss.

        Examples:
              plot sin(x)
              plot sin(x), cos(x)
              plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
              plot "datafile.1" with lines, "datafile.2" with points
              plot [t=1:10] [-pi:pi*2] tan(t), \
                   "data.1" using (tan($2)):($3/$4) smooth csplines \
                            axes x1y2 notitle with lines 5
              plot for [datafile in "spinach.dat broccoli.dat"]
        datafile

        See also sshhooww pplloott.

















   GNUPLOT 4.1                                                       89


             7744..11..  AAxxeess


             There are four possible sets of axes available; the key-
             word <axes> is used to select the axes for which a partic-
             ular line should be scaled.  xx11yy11 refers to the axes on
             the bottom and left; xx22yy22 to those on the top and right;
             xx11yy22 to those on the bottom and right; and xx22yy11 to those
             on the top and left.  Ranges specified on the pplloott command
             apply only to the first set of axes (bottom left).



             7744..22..  BBiinnaarryy


             BINARY DATA FILES:

             Some earlier versions of ggnnuupplloott automatically detected
             binary data files.  It is now necessary to provide the
             keyword bbiinnaarryy after the filename.  Adequate details of
             the file format must be given on the command line or
             extracted from the file itself for a supported binary
             ffiilleettyyppee.  In particular, there are two structures for
             binary files,  binary matrix format and binary general
             format.

             The bbiinnaarryy mmaattrriixx format contains a two dimensional array
             of 32 bit IEEE float values with an additional column and
             row of coordinate values.  As with ASCII matrix, in the
             uussiinngg list, enumeration of the coordinate row constitutes
             column 1, enumeration of the coordinate column constitutes
             column 2, and the array of values constitutes column 3.

             The bbiinnaarryy ggeenneerraall format contains an arbitrary number of
             columns for which information must be specified at the
             command line.  For example, aarrrraayy, rreeccoorrdd, ffoorrmmaatt and
             uussiinngg can indicate the size, format and dimension of data.
             There are a variety of useful commands for skipping file
             headers and changing endianess.  There are a set of com-
             mands for positioning and translating data since often
             coordinates are not part of the file when uniform sampling
             is inherent in the data.  Different from matrix binary or
             ASCII, general binary does not treat the generated columns
             as 1, 2 or 3 in the uussiinngg list.  Rather, column 1 begins
             with column 1 of the file, or as specified in the ffoorrmmaatt
             list.

             There are global default settings for the various binary
             options which may be set using the same syntax as the
             options when used as part of the ((ss))pplloott <<ffiilleennaammee>> bbiinnaarryy
             ...... command.  This syntax is sseett ddaattaaffiillee bbiinnaarryy .......  The
             general rule is that common command-line specified










   GNUPLOT 4.1                                                       90


             parameters override file-extracted parameters which over-
             ride default parameters.

             BBiinnaarryy mmaattrriixx is the default binary format when no key-
             words specific to bbiinnaarryy ggeenneerraall are given, i.e., aarrrraayy,
             rreeccoorrdd, ffoorrmmaatt, ffiilleettyyppee.

             General binary data can be entered at the command line via
             the special file name '-'.  However, this is intended for
             use through a pipe where programs can exchange binary
             data, not for keyboards.  There is no "end of record"
             character for binary data.  Gnuplot continues reading from
             a pipe until it has read the number of points declared in
             the aarrrraayy qualifier.  See bbiinnaarryy mmaattrriixx or bbiinnaarryy ggeenneerraall
             for more details.

             The iinnddeexx keyword is not supported, since the file format
             allows only one surface per file.  The eevveerryy and uussiinngg
             filters are supported.  uussiinngg operates as if the data were
             read in the above triplet form.  Binary File Splot Demo.




                  7744..22..11..  GGeenneerraall


                  General binary data in which format information is
                  not necessarily part of the file can be read by giv-
                  ing further details about the file format at the com-
                  mand line.  Although the syntax is slightly arcane to
                  the casual user, general binary is particularly use-
                  ful for application programs using gnuplot and send-
                  ing large amounts of data.

                  Syntax:
                        plot '<file_name>' {binary <binary list>} ...
                        splot '<file_name>' {binary <binary list>} ...

                  General binary format is activated by keywords in
                  <binary list> pertaining to information about file
                  structure, i.e., aarrrraayy, rreeccoorrdd, ffoorrmmaatt or ffiilleettyyppee.
                  Otherwise, matrix binary format is assumed.  (See
                  bbiinnaarryy mmaattrriixx for more details.)

                  There are some standard file types that may be read
                  for which details about the binary format may be
                  extracted automatically.  (Type sshhooww ddaattaaffiillee bbiinnaarryy
                  at the command line for a list.)  Otherwise, details
                  must be specified at the command line or set in the
                  defaults.  Keywords are described below.

                  The keyword ffiilleettyyppee in <binary list> controls the










   GNUPLOT 4.1                                                       91


                  routine used to read the file, i.e., the format of
                  the data.  For a list of the supported file types,
                  type sshhooww ddaattaaffiillee bbiinnaarryy ffiilleettyyppeess.  If no file type
                  is given, the rule is that traditional gnuplot binary
                  is assumed for sspplloott if the bbiinnaarryy keyword stands
                  alone.  In all other circumstances, for pplloott or when
                  one of the <binary list> keywords appears, a raw
                  binary file is assumed whereby the keywords specify
                  the binary format.

                  General binary data files fall into two basic
                  classes, and some files may be of both classes
                  depending upon how they are treated.  There is that
                  class for which uniform sampling is assumed and point
                  coordinates must be generated.  This is the class for
                  which full control via the <binary list> keywords
                  applies.  For this class, the settings precedence is
                  that command line parameters override in-file parame-
                  ters, which override default settings.  The other
                  class is that set of files for which coordinate
                  information is contained within the file or there is
                  possibly a non-uniform sampling such as gnuplot
                  binary.

                  Other than for the unique data files such as gnuplot
                  binary, one should think of binary data as conceptu-
                  ally the same as ASCII data.  Each point has columns
                  of information which are selected via the <<uussiinngg
                  lliisstt>> associated with uussiinngg.  When no ffoorrmmaatt string
                  is specified, gnuplot will retrieve a number of
                  binary variables equal to the largest column given in
                  the <<uussiinngg lliisstt>>.  For example, uussiinngg 11::33 will result
                  in three columns being read, of which the second will
                  be ignored.  There are default using lists based upon
                  the typical number of parameters associated with a
                  certain plot type.  For example, wwiitthh iimmaaggee has a
                  default of uussiinngg 11, while wwiitthh rrggbbiimmaaggee has a default
                  of uussiinngg 11::22::33.  Note that the special characters for
                  uussiinngg representing point/line/index generally should
                  not be used for binary data.  There are keywords in
                  <binary list> that control this.



                  7744..22..22..  AArrrraayy


                  Describes the sampling array dimensions associated
                  with the binary file.  The coordinates will be gener-
                  ated by gnuplot.  A number must be specified for each
                  dimension of the array.  For example, aarrrraayy==((1100,,2200))
                  means the underlying sampling structure is two-dimen-
                  sional with 10 points along the first (x) dimension










   GNUPLOT 4.1                                                       92


                  and 20 points along the second (y) dimension.  A neg-
                  ative number indicates that data should be read until
                  the end of file.  If there is only one dimension, the
                  parentheses may be omitted.  A colon can be used to
                  separate the dimensions for multiple records.  For
                  example, aarrrraayy==2255::3355 indicates there are two one-
                  dimensional records in the file.
                        Note:  Gnuplot version 4.2 used the syntax
                  array=128x128 rather than
                               array=(128,128). The older syntax is now
                  deprecated, but may
                               still work if your copy of gnuplot was
                  built to support
                               backwards compatibility.



                  7744..22..33..  RReeccoorrdd


                  This keyword serves the same function as aarrrraayy, hav-
                  ing the same syntax.  However, rreeccoorrdd causes gnuplot
                  to not generate coordinate information.  This is for
                  the case where such information may be included in
                  one of the columns of the binary data file.



                  7744..22..44..  SSkkiipp


                  This keyword allows you to skip sections of a binary
                  file. For instance, if the file contains a 1024 byte
                  header before the start of the data region you would
                  probably want to use
                        plot '<file_name>' binary skip=1024 ...
                  If there are multiple records in the file, you may
                  specify a leading offset for each. For example, to
                  skip 512 bytes before the 1st record and 256 bytes
                  before the second and third records
                        plot '<file_name> binary record=356:356:356
                  skip=512:256:256 ...



                  7744..22..55..  FFoorrmmaatt


                  The default binary format is a float.  For more flex-
                  ibility, the format can include details about vari-
                  able sizes.  For example, ffoorrmmaatt==""%%uucchhaarr%%iinntt%%ffllooaatt""
                  associates an unsigned character with the first using
                  column, an int with the second column and a float










   GNUPLOT 4.1                                                       93


                  with the third column.  If the number of size speci-
                  fications is less than the greatest column number,
                  the size is implicitly taken to be similar to the
                  last given variable size.

                  Furthermore, similar to the uussiinngg specification, the
                  format can include discarded columns via the ** char-
                  acter and have implicit repetition via a numerical
                  repeat-field.  For example, ffoorrmmaatt==""%%**22iinntt%%33ffllooaatt""
                  causes gnuplot to discard two ints before reading
                  three floats.  To list variable sizes, type sshhooww
                  ddaattaaffiillee bbiinnaarryy ddaattaassiizzeess.  There are a group of
                  names that are machine dependent along with their
                  sizes in bytes for the particular compilation.  There
                  is also a group of names which attempt to be machine
                  independent.



                  7744..22..66..  EEnnddiiaann


                  Often the endianess of binary data in the file does
                  not agree with the endianess used by the platform on
                  which gnuplot is running.  Several words can direct
                  gnuplot how to arrange bytes.  For example
                  eennddiiaann==lliittttllee means treat the binary file as having
                  byte significance from least to greatest. The options
                  are

                                little:  least significant to greatest
                  significance
                                   big:  greatest significance to least
                  significance
                               default:  assume file endianess is the
                  same as compiler
                           swap (swab):  Interchange the significance.
                  (If things
                                         don't look right, try this.)

                  Gnuplot can support "middle" ("pdp") endian if it is
                  compiled with that option.



                  7744..22..77..  FFiilleettyyppee


                  For some standard binary file formats gnuplot can
                  extract all the necessary information from the file
                  in question.  As an example, "format=edf" will read
                  ESRF Header File format files.  For a list of the
                  currently supported file formats, type sshhooww ddaattaaffiillee










   GNUPLOT 4.1                                                       94


                  bbiinnaarryy ffiilleettyyppeess.

                  There is a special file type called aauuttoo for which
                  gnuplot will check if the binary file's extension is
                  a quasi-standard extension for a supported format.

                  Command line keywords may be used to override set-
                  tings extracted from the file.  The settings from the
                  file override any defaults.  (See sseett ddaattaaffiillee bbiinnaarryy
                  for details.)




                       7744..22..77..11..  AAvvss


                       aavvss is one of the automatically recognized
                       binary file types for images.  AVS is an
                       extremely simple format, suitable mostly for
                       streaming between applications. It consists of 2
                       longs (xwidth, ywidth) followed by a stream of
                       pixels, each with four bytes of information
                       alpha/red/green/blue.



                       7744..22..77..22..  EEddff


                       eeddff is one of the automatically recognized
                       binary file types for images.  EDF stands for
                       ESRF Data Format, and it supports both edf and
                       ehf formats (the latter means ESRF Header For-
                       mat).  More information on specifications can be
                       found at

                         http://www.edfplus.info/specs



                       7744..22..77..33..  PPnngg


                       If gnuplot was configured to use the libgd
                       library for png/gif/jpeg output, then it can
                       also be used to read these same image types as
                       binary files.  You can use an explicit command
                             plot 'file.png' binary filetype=png
                       Or the file type will be recognized automati-
                       cally from the extension if you have previously
                       requested
                             set datafile binary filetype=auto










   GNUPLOT 4.1                                                       95


                  7744..22..88..  KKeeyywwoorrddss


                  The following keywords apply only when generating
                  coordinates from binary data files.  That is, the
                  control mapping the individual elements of a binary
                  array, matrix, or image to specific x/y/z positions.




                       7744..22..88..11..  SSccaann


                       A great deal of confusion can arise concerning
                       the relationship between how gnuplot scans a
                       binary file and the dimensions seen on the plot.
                       To lessen the confusion, conceptually think of
                       gnuplot _always_ scanning the binary file
                       point/line/plane or fast/medium/slow.  Then this
                       keyword is used to tell gnuplot how to map this
                       scanning convention to the Cartesian convention
                       shown in plots, i.e., x/y/z.  The qualifier for
                       scan is a two or three letter code representing
                       where point is assigned (first letter), line is
                       assigned (second letter), and plane is assigned
                       (third letter).  For example, ssccaann==yyxx means the
                       fastest, point-by-point, increment should be
                       mapped along the Cartesian y dimension and the
                       middle, line-by-line, increment should be mapped
                       along the x dimension.

                       When the plotting mode is pplloott, the qualifier
                       code can include the two letters x and y.  For
                       sspplloott, it can include the three letters x, y and
                       z.

                       There is nothing restricting the inherent map-
                       ping from point/line/plane to apply only to
                       Cartesian coordinates.  For this reason there
                       are cylindrical coordinate synonyms for the
                       qualifier codes where t (theta), r and z are
                       analogous to the x, y and z of Cartesian coordi-
                       nates.



                       7744..22..88..22..  TTrraannssppoossee


                       Shorthand notation for ssccaann==yyxx or ssccaann==yyxxzz.












   GNUPLOT 4.1                                                       96


                       7744..22..88..33..  DDxx,, ddyy,, ddzz


                       When gnuplot generates coordinates, it uses the
                       spacing described by these keywords.  For exam-
                       ple ddxx==1100 ddyy==2200 would mean space samples along
                       the x dimension by 10 and space samples along
                       the y dimension by 20.  ddyy cannot appear if ddxx
                       does not appear.  Similarly, ddzz cannot appear if
                       ddyy does not appear.  If the underlying dimen-
                       sions are greater than the keywords specified,
                       the spacing of the highest dimension given is
                       extended to the other dimensions.  For example,
                       if an image is being read from a file and only
                       ddxx==33..55 is given gnuplot uses a delta x and delta
                       y of 3.5.

                       The following keywords also apply only when gen-
                       erating coordinates.  However they may also be
                       used with matrix binary files.



                       7744..22..88..44..  FFlliippxx,, fflliippyy,, fflliippzz


                       Sometimes the scanning directions in a binary
                       datafile are not consistent with that assumed by
                       gnuplot.  These keywords can flip the scanning
                       direction along dimensions x, y, z.



                       7744..22..88..55..  OOrriiggiinn


                       When gnuplot generates coordinates based upon
                       transposition and flip, it attempts to always
                       position the lower left point in the array at
                       the origin, i.e., the data lies in the first
                       quadrant of a Cartesian system after transpose
                       and flip.

                       To position the array somewhere else on the
                       graph, the oorriiggiinn keyword directs gnuplot to
                       position the lower left point of the array at a
                       point specified by a tuple.  The tuple should be
                       a double for pplloott and a triple for sspplloott.  For
                       example, oorriiggiinn==((110000,,110000))::((110000,,220000)) is for two
                       records in the file and intended for plotting in
                       two dimensions. A second example, oorrii--
                       ggiinn==((00,,00,,33..55)), is for plotting in three dimen-
                       sions.










   GNUPLOT 4.1                                                       97


                       7744..22..88..66..  CCeenntteerr


                       Similar to oorriiggiinn, this keyword will position
                       the array such that its center lies at the point
                       given by the tuple.  For example, cceenntteerr==((00,,00)).
                       Center does not apply when the size of the array
                       is IInnff.



                       7744..22..88..77..  RRoottaattee


                       The transpose and flip commands provide some
                       flexibility in generating and orienting coordi-
                       nates.  However, for full degrees of freedom, it
                       is possible to apply a rotational vector
                       described by a rotational angle in two dimen-
                       sions.

                       The rroottaattee keyword applies to the two-dimen-
                       sional plane, whether it be pplloott or sspplloott.  The
                       rotation is done with respect to the positive
                       angle of the Cartesian plane.

                       The angle can be expressed in radians, radians
                       as a multiple of pi, or degrees.  For example,
                       rroottaattee==11..55770088, rroottaattee==00..55ppii and rroottaattee==9900ddeegg are
                       equivalent.

                       If oorriiggiinn is specified, the rotation is done
                       about the lower left sample point before trans-
                       lation.  Otherwise, the rotation is done about
                       the array cceenntteerr.



                       7744..22..88..88..  PPeerrppeennddiiccuullaarr


                       For sspplloott, the concept of a rotational vector is
                       implemented by a triple representing the vector
                       to be oriented normal to the two-dimensional x-y
                       plane.  Naturally, the default is (0,0,1).  Thus
                       specifying both rotate and perpendicular
                       together can orient data myriad ways in three-
                       space.

                       The two-dimensional rotation is done first, fol-
                       lowed by the three-dimensional rotation.  That
                       is, if R' is the rotational 2 x 2 matrix
                       described by an angle, and P is the 3 x 3 matrix










   GNUPLOT 4.1                                                       98


                       projecting (0,0,1) to (xp,yp,zp), let R be con-
                       structed from R' at the upper left sub-matrix, 1
                       at element 3,3 and zeros elsewhere.  Then the
                       matrix formula for translating data is v' = P R
                       v, where v is the 3 x 1 vector of data extracted
                       from the data file.  In cases where the data of
                       the file is inherently not three-dimensional,
                       logical rules are used to place the data in
                       three-space.  (E.g., usually setting the z-
                       dimension value to zero and placing 2D data in
                       the x-y plane.)



             7744..33..  DDaattaa


             Discrete data contained in a file can be displayed by
             specifying the name of the data file (enclosed in single
             or double quotes) on the pplloott command line.

             Syntax:
                   plot '<file_name>' {binary <binary list>}
                                      {{nonuniform} matrix}
                                      {index <index list> | index
             "<name>"}
                                      {every <every list>}
                                      {thru <thru expression>}
                                      {using <using list>}
                                      {smooth <option>}
                                      {volatile} {noautoscale}

             The modifiers bbiinnaarryy, iinnddeexx, eevveerryy, tthhrruu, uussiinngg, and
             ssmmooootthh are discussed separately.  In brief, bbiinnaarryy allows
             data entry from a binary file (default is ASCII), iinnddeexx
             selects which data sets in a multi-data-set file are to be
             plotted, eevveerryy specifies which points within a single data
             set are to be plotted, uussiinngg determines how the columns
             within a single record are to be interpreted (tthhrruu is a
             special case of uussiinngg), and ssmmooootthh allows for simple
             interpolation and approximation.  (sspplloott has a similar
             syntax, but does not support the ssmmooootthh and tthhrruu options.)

             The nnooaauuttoossccaallee keyword means that the points making up
             this plot will be ignored when automatically determining
             axis range limits.

             ASCII DATA FILES:

             Data files should contain at least one data point per
             record (uussiinngg can select one data point from the record).
             Records beginning with ## (and also with !! on VMS) will be
             treated as comments and ignored.  Each data point










   GNUPLOT 4.1                                                       99


             represents an (x,y) pair. For ppllootts with error bars or
             error bars with lines (see sseett ssttyyllee eerrrroorrbbaarrss or sseett
             ssttyyllee eerrrroorrlliinneess), each data point is (x,y,ydelta),
             (x,y,ylow,yhigh), (x,y,xdelta), (x,y,xlow,xhigh), or
             (x,y,xlow,xhigh,ylow,yhigh).

             In all cases, the numbers of each record of a data file
             must be separated by white space (one or more blanks or
             tabs) unless a format specifier is provided by the uussiinngg
             option. This white space divides each record into columns.
             However, whitespace inside a pair of double quotes is
             ignored when counting columns, so the following datafile
             line has three columns:
                   1.0 "second column" 3.0

             Data may be written in exponential format with the expo-
             nent preceded by the letter e or E.  The fortran exponen-
             tial specifiers d, D, q, and Q may also be used if the
             command sseett ddaattaaffiillee ffoorrttrraann is in effect.

             Only one column (the y value) need be provided.  If x is
             omitted, ggnnuupplloott provides integer values starting at 0.

             In datafiles, blank records (records with no characters
             other than blanks and a newline and/or carriage return)
             are significant.

             Single blank records designate discontinuities in a pplloott;
             no line will join points separated by a blank records (if
             they are plotted with a line style).

             Two blank records in a row indicate a break between sepa-
             rate data sets.  See iinnddeexx.

             If autoscaling has been enabled (sseett aauuttoossccaallee), the axes
             are automatically extended to include all datapoints, with
             a whole number of tic marks if tics are being drawn.  This
             has two consequences: i) For sspplloott, the corner of the sur-
             face may not coincide with the corner of the base.  In
             this case, no vertical line is drawn.  ii) When plotting
             data with the same x range on a dual-axis graph, the x
             coordinates may not coincide if the x2tics are not being
             drawn.  This is because the x axis has been autoextended
             to a whole number of tics, but the x2 axis has not.  The
             following example illustrates the problem:

                   reset; plot '-', '-' axes x2y1
                   1 1
                   19 19
                   e
                   1 1
                   19 19
                   e










   GNUPLOT 4.1                                                      100


             To avoid this, you can use the ffiixxmmiinn/ffiixxmmaaxx feature of
             the sseett aauuttoossccaallee command, which turns off the automatic
             extension of the axis range up to the next tic mark.

             Label coordinates and text can also be read from a data
             file (see llaabbeellss).





                  7744..33..11..  EEvveerryy


                  The eevveerryy keyword allows a periodic sampling of a
                  data set to be plotted.

                  In the discussion a "point" is a datum defined by a
                  single record in the file; "block" here will mean the
                  same thing as "datablock" (see gglloossssaarryy).

                  Syntax:
                        plot 'file' every {<point_incr>}
                                            {:{<block_incr>}
                                              {:{<start_point>}
                                                {:{<start_block>}
                                                  {:{<end_point>}
                                                    {:<end_block>}}}}}

                  The data points to be plotted are selected according
                  to a loop from <ssttaarrtt__ppooiinntt> to <eenndd__ppooiinntt> with
                  increment <ppooiinntt__iinnccrr> and the blocks according to a
                  loop from <ssttaarrtt__bblloocckk> to <eenndd__bblloocckk> with increment
                  <bblloocckk__iinnccrr>.

                  The first datum in each block is numbered '0', as is
                  the first block in the file.

                  Note that records containing unplottable information
                  are counted.

                  Any of the numbers can be omitted; the increments
                  default to unity, the start values to the first point
                  or block, and the end values to the last point or
                  block.  If eevveerryy is not specified, all points in all
                  lines are plotted.

                  Examples:
                        every :::3::3    # selects just the fourth
                  block ('0' is first)
                        every :::::9     # selects the first 10 blocks
                        every 2:2        # selects every other point in
                  every other block










   GNUPLOT 4.1                                                      101


                        every ::5::15    # selects points 5 through 15
                  in each block

                  See simple plot demos (simple.dem) , Non-parametric
                  splot demos , and Parametric splot demos .



                  7744..33..22..  EExxaammppllee ddaattaaffiillee


                  This example plots the data in the file "popula-
                  tion.dat" and a theoretical curve:

                        pop(x) = 103*exp((1965-x)/10)
                        set xrange [1960:1990]
                        plot 'population.dat', pop(x)

                  The file "population.dat" might contain:

                        # Gnu population in Antarctica since 1965
                           1965   103
                           1970   55
                           1975   34
                           1980   24
                           1985   10

                  Binary examples:

                        # Selects two float values (second one
                  implicit) with a float value
                        # discarded between them for an indefinite
                  length of 1D data.
                        plot '<file_name>' binary for-
                  mat="%float%*float" using 1:2 with lines

                        # The data file header contains all details
                  necessary for creating
                        # coordinates from an EDF file.
                        plot '<file_name>' binary filetype=edf with
                  image
                        plot '<file_name>.edf' binary filetype=auto
                  with image

                        # Selects three unsigned characters for compo-
                  nents of a raw RGB image
                        # and flips the y-dimension so that typical
                  image orientation (start
                        # at top left corner) translates to the Carte-
                  sian plane.  Pixel
                        # spacing is given and there are two images in
                  the file.  One of them
                        # is translated via origin.










   GNUPLOT 4.1                                                      102


                        plot '<file_name>' binary
                  array=(512,1024):(1024,512) format='%uchar' \
                             dx=2:1 dy=1:2 origin=(0,0):(1024,1024)
                  flipy u 1:2:3 w rgbimage

                        # Four separate records in which the coordi-
                  nates are part of the
                        # data file.  The file was created with a endi-
                  aness different from
                        # the system on which gnuplot is running.
                        splot '<file_name>' binary record=30:30:29:26
                  endian=swap u 1:2:3

                        # Same input file, but this time we skip the
                  1st and 3rd records
                        splot '<file_name>' binary record=30:26
                  skip=360:348 endian=swap u 1:2:3


                  See also bbiinnaarryy mmaattrriixx.



                  7744..33..33..  IInnddeexx


                  The iinnddeexx keyword allows you to select specific data
                  sets in a multi-data-set file for plotting.

                  Syntax:
                        plot 'file' index { <m>{:<n>{:<p>}} | "<name>"
                  }

                  Data sets are separated by pairs of blank records.
                  iinnddeexx <<mm>> selects only set <m>; iinnddeexx <<mm>>::<<nn>> selects
                  sets in the range <m> to <n>; and iinnddeexx <<mm>>::<<nn>>::<<pp>>
                  selects indices <m>, <m>+<p>, <m>+2<p>, etc., but
                  stopping at <n>.  Following C indexing, the index 0
                  is assigned to the first data set in the file.  Spec-
                  ifying too large an index results in an error mes-
                  sage.  If <p> is specified but <n> is left blank then
                  every <p>-th dataset is read until the end of the
                  file.  If iinnddeexx is not specified, the entire file is
                  plotted as a single data set.

                  Example:
                        plot 'file' index 4:5

                  For each point in the file, the index value of the
                  data set it appears in is available via the pseudo-
                  column ccoolluummnn((--22)).  This leads to an alternative way
                  of distinguishing individual data sets within a file
                  as shown below.  This is more awkward than the iinnddeexx










   GNUPLOT 4.1                                                      103


                  command if all you are doing is selecting one data
                  set for plotting, but is very useful if you want to
                  assign different properties to each data set.  See
                  ppsseeuuddooccoolluummnnss, llcc vvaarriiaabbllee.

                  Example:
                        plot 'file' using 1:(column(-2)==4 ? $2 : NaN)
                  # very awkward
                        plot 'file' using 1:2:(column(-2)) linecolor
                  variable # very useful!

                  iinnddeexx ''<<nnaammee>>'' selects the data set with name
                  '<name>'.  Names are assigned to data sets in comment
                  lines.  The comment character and leading white space
                  are removed from the comment line.  If the resulting
                  line starts with <name>, the following data set is
                  now named <name> and can be selected.

                  Example:
                        plot 'file' index 'Population'

                  Please note that every comment that starts with
                  <name> will name the following data set.  To avoid
                  problems it may be useful to choose a naming scheme
                  like '== Population ==' or '[Population]'.




                  7744..33..44..  SSmmooootthh


                  ggnnuupplloott includes a few general-purpose routines for
                  interpolation and approximation of data; these are
                  grouped under the ssmmooootthh option.  More sophisticated
                  data processing may be performed by preprocessing the
                  data externally or by using ffiitt with an appropriate
                  model.

                  Syntax:
                        smooth {unique | frequency | cumulative | cnor-
                  mal | kdensity
                                       | csplines | acsplines | bezier
                  | sbezier}

                  uunniiqquuee, ffrreeqquueennccyy, ccuummuullaattiivvee and ccnnoorrmmaall plot the
                  data after making them monotonic.  Each of the other
                  routines uses the data to determine the coefficients
                  of a continuous curve between the endpoints of the
                  data.  This curve is then plotted in the same manner
                  as a function, that is, by finding its value at uni-
                  form intervals along the abscissa (see sseett ssaammpplleess)
                  and connecting these points with straight line










   GNUPLOT 4.1                                                      104


                  segments (if a line style is chosen).

                  If aauuttoossccaallee is in effect, the ranges will be com-
                  puted such that the plotted curve lies within the
                  borders of the graph.

                  If aauuttoossccaallee is not in effect, and the smooth option
                  is either aaccsspplliinnee or ccsspplliinnee, the sampling of the
                  generated curve is done across the intersection of
                  the x range covered by the input data and the fixed
                  abscissa range as defined by sseett xxrraannggee.

                  If too few points are available to allow the selected
                  option to be applied, an error message is produced.
                  The minimum number is one for uunniiqquuee and ffrreeqquueennccyy,
                  four for aaccsspplliinneess, and three for the others.

                  The ssmmooootthh options have no effect on function plots.




                       7744..33..44..11..  AAccsspplliinneess


                       The aaccsspplliinneess option approximates the data with
                       a "natural smoothing spline".  After the data
                       are made monotonic in x (see ssmmooootthh uunniiqquuee), a
                       curve is piecewise constructed from segments of
                       cubic polynomials whose coefficients are found
                       by the weighting the data points; the weights
                       are taken from the third column in the data
                       file.  That default can be modified by the third
                       entry in the uussiinngg list, e.g.,
                             plot 'data-file' using 1:2:(1.0) smooth
                       acsplines

                       Qualitatively, the absolute magnitude of the
                       weights determines the number of segments used
                       to construct the curve.  If the weights are
                       large, the effect of each datum is large and the
                       curve approaches that produced by connecting
                       consecutive points with natural cubic splines.
                       If the weights are small, the curve is composed
                       of fewer segments and thus is smoother; the lim-
                       iting case is the single segment produced by a
                       weighted linear least squares fit to all the
                       data.  The smoothing weight can be expressed in
                       terms of errors as a statistical weight for a
                       point divided by a "smoothing factor" for the
                       curve so that (standard) errors in the file can
                       be used as smoothing weights.











   GNUPLOT 4.1                                                      105


                       Example:
                             sw(x,S)=1/(x*x*S)
                             plot 'data_file' using 1:2:(sw($3,100))
                       smooth acsplines



                       7744..33..44..22..  BBeezziieerr


                       The bbeezziieerr option approximates the data with a
                       Bezier curve of degree n (the number of data
                       points) that connects the endpoints.



                       7744..33..44..33..  CCsspplliinneess


                       The ccsspplliinneess option connects consecutive points
                       by natural cubic splines after rendering the
                       data monotonic (see ssmmooootthh uunniiqquuee).



                       7744..33..44..44..  SSbbeezziieerr


                       The ssbbeezziieerr option first renders the data mono-
                       tonic (uunniiqquuee) and then applies the bbeezziieerr algo-
                       rithm.



                       7744..33..44..55..  UUnniiqquuee


                       The uunniiqquuee option makes the data monotonic in x;
                       points with the same x-value are replaced by a
                       single point having the average y-value.  The
                       resulting points are then connected by straight
                       line segments.



                       7744..33..44..66..  FFrreeqquueennccyy


                       The ffrreeqquueennccyy option makes the data monotonic in
                       x; points with the same x-value are replaced by
                       a single point having the summed y-values.  The
                       resulting points are then connected by straight
                       line segments.  See also smooth.dem










   GNUPLOT 4.1                                                      106


                       7744..33..44..77..  CCuummuullaattiivvee


                       The ccuummuullaattiivvee option makes the data monotonic
                       in x; points with the same x-value are replaced
                       by a single point containing the cumulative sum
                       of y-values of all data points with lower x-val-
                       ues (i.e. to the left of the current data
                       point). This can be used to obtain a cumulative
                       distribution function from data.  See also
                       smooth.dem



                       7744..33..44..88..  CCnnoorrmmaall


                       The ccnnoorrmmaall option makes the data monotonic in x
                       and normalises the y-values onto the range
                       [0:1].  Points with the same x-value are
                       replaced by a single point containing the cumu-
                       lative sum of y-values of all data points with
                       lower x-values (i.e. to the left of the current
                       data point) divided by the total sum of all y-
                       values. This can be used to obtain a normalised
                       cumulative distribution function from data (use-
                       ful when comparing sets of samples with differ-
                       ing numbers of members).  See also smooth.dem




                       7744..33..44..99..  KKddeennssiittyy


                       The kkddeennssiittyy option is a way to plot a kernel
                       density estimate (which is a smooth histogram)
                       for a random collection of points, using Gaus-
                       sian kernels.  A Gaussian is placed at the loca-
                       tion of each point in the first column and the
                       sum of all these Gaussians is plotted as a func-
                       tion. The value in the second column is taken as
                       weight of the Gaussian. (To obtain a normalized
                       histogram, this should be 1/number-of-points).
                       The value of the third column, if supplied, is
                       taken as the bandwidth for the kernels. If only
                       two columns have been specified, or if the value
                       of the third column is zero or less, gnuplot
                       calculates the bandwidth which would be optimal
                       if the input data was normally distributed.
                       (This will usually be a very conservative, i.e.
                       broad bandwidth.)











   GNUPLOT 4.1                                                      107


                  7744..33..55..  SSppeecciiaall--ffiilleennaammeess


                  There are a few filenames that have a special mean-
                  ing:  '', '-', '+' and '++'.

                  The empty filename '' tells gnuplot to re-use the
                  previous input file in the same plot command. So to
                  plot two columns from the same input file:

                        plot 'filename' using 1:2, '' using 1:3

                  The special filenames '+' and '++' are a mechanism to
                  allow the full range of uussiinngg specifiers and plot
                  styles with in-line functions.  Normally a function
                  plot can only have a single y (or z) value associated
                  with each sampled point.  The pseudo-file '+' treats
                  the sampled points as column 1, and allows additional
                  column values to be specified via a uussiinngg specifica-
                  tion, just as for a true input file.  The number of
                  samples returned is controlled by sseett ssaammpplleess.  Exam-
                  ple:

                        plot '+' using ($1):(sin($1)):(sin($1)**2) with
                  filledcurves

                  Similarly the pseudo-file '++' returns 2 columns of
                  data forming a regular grid of [x,y] coordinates with
                  the number of points along x controlled by sseett ssaamm--
                  pplleess and the number of points along y controlled by
                  sseett iissoossaammpplleess.  You must set xrange and yrange
                  before plotting '++'.  Examples:

                        splot '++' using 1:2:(sin($1)*sin($2)) with
                  pm3d
                        plot '++' using 1:2:(sin($1)*sin($2)) with
                  image

                  The special filename ''--'' specifies that the data are
                  inline; i.e., they follow the command.  Only the data
                  follow the command; pplloott options like filters,
                  titles, and line styles remain on the pplloott command
                  line.  This is similar to << in unix shell script,
                  and $DECK in VMS DCL.  The data are entered as though
                  they are being read from a file, one data point per
                  record.  The letter "e" at the start of the first
                  column terminates data entry.  The uussiinngg option can
                  be applied to these data---using it to filter them
                  through a function might make sense, but selecting
                  columns probably doesn't!

                  ''--'' is intended for situations where it is useful to
                  have data and commands together, e.g., when ggnnuupplloott










   GNUPLOT 4.1                                                      108


                  is run as a sub-process of some front-end applica-
                  tion.  Some of the demos, for example, might use this
                  feature.  While pplloott options such as iinnddeexx and eevveerryy
                  are recognized, their use forces you to enter data
                  that won't be used.  For example, while

                        plot '-' index 0, '-' index 1
                        2
                        4
                        6


                        10
                        12
                        14
                        e
                        2
                        4
                        6


                        10
                        12
                        14
                        e

                  does indeed work,

                        plot '-', '-'
                        2
                        4
                        6
                        e
                        10
                        12
                        14
                        e

                  is a lot easier to type.

                  If you use ''--'' with rreepplloott, you may need to enter the
                  data more than once.  See rreepplloott, rreeffrreesshh.

                  A blank filename ('') specifies that the previous
                  filename should be reused.  This can be useful with
                  things like

                        plot 'a/very/long/filename' using 1:2, '' using
                  1:3, '' using 1:4

                  (If you use both ''--'' and '''' on the same pplloott command,
                  you'll need to have two sets of inline data, as in
                  the example above.)










   GNUPLOT 4.1                                                      109


                  On systems with a popen function, the datafile can be
                  piped through a shell command by starting the file
                  name with a '<'.  For example,

                        pop(x) = 103*exp(-x/10)
                        plot "< awk '{print $1-1965, $2}' popula-
                  tion.dat", pop(x)

                  would plot the same information as the first popula-
                  tion example but with years since 1965 as the x axis.
                  If you want to execute this example, you have to
                  delete all comments from the data file above or sub-
                  stitute the following command for the first part of
                  the command above (the part up to the comma):

                        plot "< awk '$0 !~ /^#/ {print $1-1965, $2}'
                  population.dat"

                  While this approach is most flexible, it is possible
                  to achieve simple filtering with the uussiinngg or tthhrruu
                  keywords.

                  On systems with an fdopen() function, data can be
                  read from an arbitrary file descriptor attached to
                  either a file or pipe.  To read from file descriptor
                  nn use ''<<&&nn''.  This allows you to easily pipe in sev-
                  eral data files in a single call from a POSIX shell:

                        $ gnuplot -p -e "plot '<&3', '<&4'" 3<data-3
                  4<data-4
                        $ ./gnuplot 5< <(myprogram -with -options)
                        gnuplot> plot '<&5'



                  7744..33..66..  TThhrruu


                  The tthhrruu function is provided for backward compati-
                  bility.

                  Syntax:
                        plot 'file' thru f(x)

                  It is equivalent to:

                        plot 'file' using 1:(f($2))

                  While the latter appears more complex, it is much
                  more flexible.  The more natural

                        plot 'file' thru f(y)











   GNUPLOT 4.1                                                      110


                  also works (i.e. you can use y as the dummy vari-
                  able).

                  tthhrruu is parsed for sspplloott and ffiitt but has no effect.



                  7744..33..77..  UUssiinngg


                  The most common datafile modifier is uussiinngg.  It tells
                  the program which columns of data in the input file
                  are to be plotted.

                  Syntax:
                        plot 'file' using <entry> {:<entry> {:<entry>
                  ...}} {'format'}

                  If a format is specified, it is used to read in each
                  datafile record using the C library 'scanf' function.
                  Otherwise the record is interpreted as consisting of
                  columns (fields) of data separated by whitespace
                  (spaces and/or tabs), but see ddaattaaffiillee sseeppaarraattoorr.

                  Each <entry> may be a simple column number that
                  selects the value from one field of the input file, a
                  string that matches a column label in the first line
                  of a data set, an expression enclosed in parentheses,
                  or a special function not enclosed in parentheses
                  such as xticlabels(2).

                  If the entry is an expression in parentheses, then
                  the function column(N) may be used to indicate the
                  value in column N. That is, column(1) refers to the
                  first item read, column(2) to the second, and so on.
                  The special symbols $1, $2, ... are shorthand for
                  column(1), column(2) ...  The function vvaalliidd((NN)) tests
                  whether the value in the Nth column is a valid num-
                  ber.  If each column of data in the input file con-
                  tains a label in the first row rather than a data
                  value, this label can be used to identify the column
                  on input and/or in the plot legend. The column()
                  function can be used to select an input column by
                  label rather than by column number.  For example, if
                  the data file contains
                        Height    Weight    Age
                        val1      val1      val1
                        ...       ...       ...
                  then the following plot commands are all equivalent
                        plot 'datafile' using 3:1, '' using 3:2
                        plot 'datafile' using (column("Age")):(col-
                  umn(1)), \
                                     '' using










   GNUPLOT 4.1                                                      111


                  (column("Age")):(column(2))
                        plot 'datafile' using "Age":"Height", '' using
                  "Age":"Weight"

                  The full string must match. Comparison is case-sensi-
                  tive.  To use the column labels in the plot legend,
                  use sseett kkeeyy aauuttoottiittllee ccoolluummnnhheeaadd.

                  In addition to the actual columns 1...N in the input
                  data file, gnuplot presents data from several
                  "pseudo-columns" that hold bookkeeping information.
                  E.g. $0 or column(0) returns the sequence number of
                  this data record within a dataset.  Please see ppsseeuu--
                  ddooccoolluummnnss.

                  An empty <entry> will default to its order in the
                  list of entries.  For example, uussiinngg ::::44 is inter-
                  preted as uussiinngg 11::22::44.

                  If the uussiinngg list has only a single entry, that
                  <entry> will be used for y and the data point number
                  (pseudo-column $0) is used for x; for example, "pplloott
                  ''ffiillee'' uussiinngg 11" is identical to "pplloott ''ffiillee'' uussiinngg
                  00::11".  If the uussiinngg list has two entries, these will
                  be used for x and y.  See sseett ssttyyllee and ffiitt for
                  details about plotting styles that make use of data
                  from additional columns of input.

                  'scanf' accepts several numerical specifications but
                  ggnnuupplloott requires all inputs to be double-precision
                  floating-point variables, so "%lf" is essentially the
                  only permissible specifier.  A format string given by
                  the user must contain at least one such input speci-
                  fier, and no more than seven of them.  'scanf'
                  expects to see white space---a blank, tab ("\t"),
                  newline ("\n"), or formfeed ("\f")---between numbers;
                  anything else in the input stream must be explicitly
                  skipped.

                  Note that the use of "\t", "\n", or "\f" requires use
                  of double-quotes rather than single-quotes.




                       7744..33..77..11..  UUssiinngg__eexxaammpplleess


                       This creates a plot of the sum of the 2nd and
                       3rd data against the first: The format string
                       specifies comma- rather than space-separated
                       columns.  The same result could be achieved by
                       specifying sseett ddaattaaffiillee sseeppaarraattoorr "",,"".










   GNUPLOT 4.1                                                      112


                             plot 'file' using 1:($2+$3) '%lf,%lf,%lf'

                       In this example the data are read from the file
                       "MyData" using a more complicated format:
                             plot 'MyData' using "%*lf%lf%*20[^\n]%lf"

                       The meaning of this format is:

                             %*lf        ignore a number
                             %lf         read a double-precision number
                       (x by default)
                             %*20[^\n]   ignore 20 non-newline charac-
                       ters
                             %lf         read a double-precision number
                       (y by default)

                       One trick is to use the ternary ??:: operator to
                       filter data:

                             plot 'file' using 1:($3>10 ? $2 : 1/0)

                       which plots the datum in column two against that
                       in column one provided the datum in column three
                       exceeds ten.  11//00 is undefined; ggnnuupplloott quietly
                       ignores undefined points, so unsuitable points
                       are suppressed.  Or you can use the pre-defined
                       variable NaN to achieve the same result.

                       In fact, you can use a constant expression for
                       the column number, provided it doesn't start
                       with an opening parenthesis; constructs like
                       uussiinngg 00++((ccoommpplliiccaatteedd eexxpprreessssiioonn)) can be used.
                       The crucial point is that the expression is
                       evaluated once if it doesn't start with a left
                       parenthesis, or once for each data point read if
                       it does.

                       If timeseries data are being used, the time can
                       span multiple columns.  The starting column
                       should be specified.  Note that the spaces
                       within the time must be included when calculat-
                       ing starting columns for other data.  E.g., if
                       the first element on a line is a time with an
                       embedded space, the y value should be specified
                       as column three.

                       It should be noted that pplloott ''ffiillee'', pplloott ''ffiillee''
                       uussiinngg 11::22, and pplloott ''ffiillee'' uussiinngg (($$11))::(($$22)) can
                       be subtly different: 1) if ffiillee has some lines
                       with one column and some with two, the first
                       will invent x values when they are missing, the
                       second will quietly ignore the lines with one
                       column, and the third will store an undefined










   GNUPLOT 4.1                                                      113


                       value for lines with one point (so that in a
                       plot with lines, no line joins points across the
                       bad point); 2) if a line contains text at the
                       first column, the first will abort the plot on
                       an error, but the second and third should qui-
                       etly skip the garbage.

                       In fact, it is often possible to plot a file
                       with lots of lines of garbage at the top simply
                       by specifying

                             plot 'file' using 1:2

                       However, if you want to leave text in your data
                       files, it is safer to put the comment character
                       (#) in the first column of the text lines.



                       7744..33..77..22..  PPsseeuuddooccoolluummnnss


                       Expressions in the uussiinngg clause of a plot state-
                       ment can refer to additional bookkeeping values
                       in addition to the actual data values contained
                       in the input file. These are contained in "pseu-
                       docolumns".
                             column(0)   The sequential order of each
                       point within a data set.
                                         The counter starts at 0 and is
                       reset by two sequential blank
                                         records.  The shorthand form
                       $0 is available.
                             column(-1)  This counter starts at 0 and
                       is reset by a single blank line.
                                         This corresponds to the data
                       line in array or grid data.
                             column(-2)  The index number of the cur-
                       rent data set within a file that
                                         contains multiple data sets.
                       See `index`.



                       7744..33..77..33..  XXttiiccllaabbeellss


                       Axis tick labels can be generated via a string
                       function, usually taking a data column as an
                       argument. The simplest form uses the data column
                       itself as a string. That is,  xticlabels(N) is
                       shorthand for xticlabels(stringcolumn(N)).  This
                       example uses the contents of column 3 as x-axis










   GNUPLOT 4.1                                                      114


                       tick labels.

                             plot 'datafile' using <xcol>:<ycol>:xti-
                       clabels(3) with <plotstyle>

                       Axis tick labels may be generated for any of the
                       plot axes: x x2 y y2 z.  The ttiiccllaabbeellss((<<llaabbeell--
                       ccooll>>)) specifiers must come after all of the data
                       coordinate specifiers in the uussiinngg portion of
                       the command.  For each data point which has a
                       valid set of X,Y[,Z] coordinates, the string
                       value given to xticlabels() is added to the list
                       of xtic labels at the same X coordinate as the
                       point it belongs to. xxttiiccllaabbeellss(()) may be short-
                       ened to xxttiicc(()) and so on.

                       Example:

                             splot "data" using
                       2:4:6:xtic(1):ytic(3):ztic(6)

                       In this example the x and y axis tic labels are
                       taken from different columns than the x and y
                       coordinate values. The z axis tics, however, are
                       generated from the z coordinate of the corre-
                       sponding point.

                       Example:

                             plot "data" using 1:2:xtic( $3 > 10. ? "A"
                       : "B" )

                       This example shows the use of a string-valued
                       function to generate x-axis tick labels. Each
                       point in the data file generates a tick mark on
                       x labeled either "A" or "B" depending on the
                       value in column 3.



                       7744..33..77..44..  XX22ttiiccllaabbeellss


                       See pplloott uussiinngg xxttiiccllaabbeellss.



                       7744..33..77..55..  YYttiiccllaabbeellss


                       See pplloott uussiinngg xxttiiccllaabbeellss.












   GNUPLOT 4.1                                                      115


                       7744..33..77..66..  YY22ttiiccllaabbeellss


                       See pplloott uussiinngg xxttiiccllaabbeellss.



                       7744..33..77..77..  ZZttiiccllaabbeellss


                       See pplloott uussiinngg xxttiiccllaabbeellss.



                  7744..33..88..  VVoollaattiillee


                  The vvoollaattiillee keyword in a plot command indicates that
                  the data previously read from the input stream or
                  file may not be available for re-reading.  This tells
                  the program to use rreeffrreesshh rather than rreepplloott com-
                  mands whenever possible.  See rreeffrreesshh.



             7744..44..  EErrrroorrbbaarrss


             Error bars are supported for 2D data file plots by reading
             one to four additional columns (or uussiinngg entries); these
             additional values are used in different ways by the vari-
             ous errorbar styles.

             In the default situation, ggnnuupplloott expects to see three,
             four, or six numbers on each line of the data
             file---either

                   (x, y, ydelta),
                   (x, y, ylow, yhigh),
                   (x, y, xdelta),
                   (x, y, xlow, xhigh),
                   (x, y, xdelta, ydelta), or
                   (x, y, xlow, xhigh, ylow, yhigh).

             The x coordinate must be specified.  The order of the num-
             bers must be exactly as given above, though the uussiinngg
             qualifier can manipulate the order and provide values for
             missing columns.  For example,

                   plot 'file' with errorbars
                   plot 'file' using 1:2:(sqrt($1)) with xerrorbars
                   plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyer-
             rorbars










   GNUPLOT 4.1                                                      116


             The last example is for a file containing an unsupported
             combination of relative x and absolute y errors.  The
             uussiinngg entry generates absolute x min and max from the rel-
             ative error.

             The y error bar is a vertical line plotted from (x, ylow)
             to (x, yhigh). If ydelta is specified instead of ylow and
             yhigh, ylow = y - ydelta and yhigh = y + ydelta are
             derived. If there are only two numbers on the record,
             yhigh and ylow are both set to y. The x error bar is a
             horizontal line computed in the same fashion. To get lines
             plotted between the data points, pplloott the data file twice,
             once with errorbars and once with lines (but remember to
             use the nnoottiittllee option on one to avoid two entries in the
             key). Alternately, use the errorlines command (see eerrrroorr--
             lliinneess).

             The error bars have crossbars at each end unless sseett bbaarrss
             is used (see sseett bbaarrss for details).

             If autoscaling is on, the ranges will be adjusted to
             include the error bars.

             See also errorbar demos.

             See pplloott uussiinngg, pplloott wwiitthh, and sseett ssttyyllee for more informa-
             tion.



             7744..55..  EErrrroorrlliinneess


             Lines with error bars are supported for 2D data file plots
             by reading one to four additional columns (or uussiinngg
             entries); these additional values are used in different
             ways by the various errorlines styles.

             In the default situation, ggnnuupplloott expects to see three,
             four, or six numbers on each line of the data
             file---either

                   (x, y, ydelta),
                   (x, y, ylow, yhigh),
                   (x, y, xdelta),
                   (x, y, xlow, xhigh),
                   (x, y, xdelta, ydelta), or
                   (x, y, xlow, xhigh, ylow, yhigh).

             The x coordinate must be specified. The order of the num-
             bers must be exactly as given above, though the uussiinngg
             qualifier can manipulate the order and provide values for
             missing columns. For example,










   GNUPLOT 4.1                                                      117


                   plot 'file' with errorlines
                   plot 'file' using 1:2:(sqrt($1)) with xerrorlines
                   plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyer-
             rorlines

             The last example is for a file containing an unsupported
             combination of relative x and absolute y errors. The uussiinngg
             entry generates absolute x min and max from the relative
             error.

             The y error bar is a vertical line plotted from (x, ylow)
             to (x, yhigh). If ydelta is specified instead of ylow and
             yhigh, ylow = y - ydelta and yhigh = y + ydelta are
             derived. If there are only two numbers on the record,
             yhigh and ylow are both set to y. The x error bar is a
             horizontal line computed in the same fashion.

             The error bars have crossbars at each end unless sseett bbaarrss
             is used (see sseett bbaarrss for details).

             If autoscaling is on, the ranges will be adjusted to
             include the error bars.

             See pplloott uussiinngg, pplloott wwiitthh, and sseett ssttyyllee for more informa-
             tion.



             7744..66..  FFuunnccttiioonnss


             Built-in or user-defined functions can be displayed by the
             pplloott and sspplloott commands in addition to, or instead of,
             data read from a file. The requested function is evaluated
             by sampling at regular intervals spanning the independent
             axis range[s]. See sseett ssaammpplleess and sseett iissoossaammpplleess.  Exam-
             ple:
                   approx(ang) = ang - ang**3 / (3*2)
                   plot sin(x) title "sin(x)", approx(x) title "approx-
             imation"

             To set a default plot style for functions, see sseett ssttyyllee
             ffuunnccttiioonn.  For information on built-in functions, see
             eexxpprreessssiioonnss ffuunnccttiioonnss.  For information on defining your
             own functions, see uusseerr--ddeeffiinneedd.



             7744..77..  PPaarraammeettrriicc


             When in parametric mode (sseett ppaarraammeettrriicc) mathematical
             expressions must be given in pairs for pplloott and in










   GNUPLOT 4.1                                                      118


             triplets for sspplloott.

             Examples:
                   plot sin(t),t**2
                   splot cos(u)*cos(v),cos(u)*sin(v),sin(u)

             Data files are plotted as before, except any preceding
             parametric function must be fully specified before a data
             file is given as a plot.  In other words, the x parametric
             function (ssiinn((tt)) above) and the y parametric function
             (tt****22 above) must not be interrupted with any modifiers or
             data functions; doing so will generate a syntax error
             stating that the parametric function is not fully speci-
             fied.

             Other modifiers, such as wwiitthh and ttiittllee, may be specified
             only after the parametric function has been completed:

                   plot sin(t),t**2 title 'Parametric example' with
             linespoints

             See also Parametric Mode Demos.



             7744..88..  RRaannggeess


             The optional axis ranges at the start of a plot command
             specify the region of the graph that will be displayed.
             These override any ranges established by a previous sseett
             rraannggee statement.

             Syntax:
                   [{<dummy-var>=}{{<min>}:{<max>}}]
                   [{{<min>}:{<max>}}]

             The first form applies to the independent variable (xxrraannggee
             or ttrraannggee, if in parametric mode).  The second form
             applies to the dependent variable yyrraannggee (and xxrraannggee, too,
             if in parametric mode).  <dummy-var> is a new name for the
             independent variable.  (The defaults may be changed with
             sseett dduummmmyy.)  The optional <min> and <max> terms can be
             constant expressions or *.

             In non-parametric mode, the order in which ranges must be
             given is xxrraannggee and yyrraannggee.

             In parametric mode, the order for the pplloott command is
             ttrraannggee, xxrraannggee, and yyrraannggee.  The following pplloott command
             shows setting the ttrraannggee to [-pi:pi], the xxrraannggee to
             [-1.3:1.3] and the yyrraannggee to [-1:1] for the duration of
             the graph:










   GNUPLOT 4.1                                                      119


                   plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2

             Note that the x2range and y2range cannot be specified
             here---sseett xx22rraannggee and sseett yy22rraannggee must be used.

             Ranges are interpreted in the order listed above for the
             appropriate mode.  Once all those needed are specified, no
             further ones must be listed, but unneeded ones cannot be
             skipped---use an empty range [[]] as a placeholder.

             ** can be used to allow autoscaling of either of min and
             max.  See also sseett aauuttoossccaallee.

             Ranges specified on the pplloott or sspplloott command line affect
             only that graph; use the sseett xxrraannggee, sseett yyrraannggee, etc.,
             commands to change the default ranges for future graphs.

             With time data, you must provide the range (in the same
             manner as the time appears in the datafile) within quotes.
             ggnnuupplloott uses the ttiimmeeffmmtt string to read the value---see
             sseett ttiimmeeffmmtt.

             Examples:

             This uses the current ranges:
                   plot cos(x)

             This sets the x range only:
                   plot [-10:30] sin(pi*x)/(pi*x)

             This is the same, but uses t as the dummy-variable:
                   plot [t = -10 :30]  sin(pi*t)/(pi*t)

             This sets both the x and y ranges:
                   plot [-pi:pi] [-3:3]  tan(x), 1/x

             This sets only the y range, and turns off autoscaling on
             both axes:
                   plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)

             This sets xmax and ymin only:
                   plot [:200] [-pi:]  exp(sin(x))

             This sets the x range for a timeseries:
                   set timefmt "%d/%m/%y %H:%M"
                   plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'

















   GNUPLOT 4.1                                                      120


             7744..99..  IItteerraattiioonn


             If many similar files or functions are to be plotted
             together, it may be convenient to do so by iterating over
             a shared plot command.

             Syntax:
                   plot for [<variable> = <start> : <end> {:<incre-
             ment>}]
                   plot for [<variable> in "string of words"]

             The scope of an iteration ends at the next comma or the
             end of the command, whichever comes first.  Iteration can
             not be nested.

             This will plot one curve, sin(3x), because iteration ends
             at the comma
                   plot for [i=1:3] j=i, sin(j*x)
             This will plot three curves because there is no comma
             after the definition of j
                   plot for [i=1:3] j=i sin(j*x)

             Example:
                   plot for [dataset in "apples bananas"] dataset."dat"
             title dataset

             In this example iteration is used both to generate a file
             name and a corresponding title.

             Example:
                   file(n) = sprintf("dataset_%d.dat",n)
                   splot for [i=1:10] file(i) title sprintf("dataset
             %d",i)

             This example defines a string-valued function that gener-
             ates file names, and plots ten such files together. The
             iteration variable ('i' in this example) is treated as an
             integer, and may be used more than once.

             Example:
                   set key left
                   plot for [n=1:4] x**n sprintf("%d",n)

             This example plots a family of functions.

             Example:
                   list = "apple banana cabbage daikon eggplant"
                   item(n) = word(list,n)
                   plot for [i=1:words(list)] item[i].".dat" title
             item(i)
                   list = "new stuff"
                   replot










   GNUPLOT 4.1                                                      121


             This example steps through a list and plots once per item.
             Because the items are retrieved dynamically, you can
             change the list and then replot.

             Example:
                   list = "apple banana cabbage daikon eggplant"
                   plot for [i in list] i.".dat" title i
                   list = "new stuff"
                   replot

             This is example does exactly the same thing as the previ-
             ous example, but uses the string iterator form of the com-
             mand rather than an integer iterator.




             7744..1100..  TTiittllee


             By default each plot is listed in the key by the corre-
             sponding function or file name. You can give an explicit
             plot title instead using the ttiittllee option.

             Syntax:
                   title <text> | notitle [<ignored text>]
                   title columnheader | title columnheader(N)

             where <text> is a quoted string or an expression that
             evaluates to a string.  The quotes will not be shown in
             the key.

             There is also an option that will interpret the first
             entry in a column of input data (i.e. the column header)
             as a text field, and use it as the key title.  See ddaattaass--
             ttrriinnggss.  This can be made the default by specifying sseett
             kkeeyy aauuttoottiittllee ccoolluummnnhheeaadd.

             The line title and sample can be omitted from the key by
             using the keyword nnoottiittllee.  A null title (ttiittllee '''') is
             equivalent to nnoottiittllee.  If only the sample is wanted, use
             one or more blanks (ttiittllee '' '').  If nnoottiittllee is followed by
             a string this string is ignored.

             If kkeeyy aauuttoottiittlleess is set (which is the default) and nei-
             ther ttiittllee nor nnoottiittllee are specified the line title is the
             function name or the file name as it appears on the pplloott
             command.  If it is a file name, any datafile modifiers
             specified will be included in the default title.

             The layout of the key itself (position, title justifica-
             tion, etc.) can be controlled by sseett kkeeyy.  Please see sseett
             kkeeyy for details.










   GNUPLOT 4.1                                                      122


             Examples:

             This plots y=x with the title 'x':
                   plot x

             This plots x squared with title "x^2" and file "data.1"
             with title "measured data":
                   plot x**2 title "x^2", 'data.1' t "measured data"

             This puts an untitled circular border around a polar
             graph:
                   set polar; plot my_function(t), 1 notitle

             Plot multiple columns of data, each of which contains its
             own title in the file
                   plot for [i=1:4] 'data' using i title columnhead




             7744..1111..  WWiitthh


             Functions and data may be displayed in one of a large num-
             ber of styles.  The wwiitthh keyword provides the means of
             selection.

             Syntax:
                   with <style> { {linestyle | ls <line_style>}
                                  | {{linetype  | lt <line_type>}
                                     {linewidth | lw <line_width>}
                                     {linecolor | lc <colorspec>}
                                     {pointtype | pt <point_type>}
                                     {pointsize | ps <point_size>}
                                     {fill | fs <fillstyle>}
                                     {nohidden3d} {nocontours} {nosur-
             face}
                                     {palette}}
                                }


             where <style> is one of

                  lines        dots       steps     errorbars     xer-
             rorbar    xyerrorlines
                  points       impulses   fsteps    errorlines    xer-
             rorlines  yerrorbars
                  linespoints  labels     histeps   financebars   xyer-
             rorbars  yerrorlines
                                                    vectors
             or
                   boxes            candlesticks   image      circles
                   boxerrorbars     filledcurves   rgbimage   ellipses










   GNUPLOT 4.1                                                      123


                   boxxyerrorbars   histograms     rgbalpha   pm3d
                   boxplot

             The first group of styles have associated line, point, and
             text properties.  The second group of styles also have
             fill properties.  See ffiillllssttyyllee.  Some styles have further
             sub-styles.  See pplloottttiinngg ssttyylleess for details of each.

             A default style may be chosen by sseett ssttyyllee ffuunnccttiioonn and
             sseett ssttyyllee ddaattaa.

             By default, each function and data file will use a differ-
             ent line type and point type, up to the maximum number of
             available types.  All terminal drivers support at least
             six different point types, and re-use them, in order, if
             more are required.  To see the complete set of line and
             point types available for the current terminal, type tteesstt.

             If you wish to choose the line or point type for a single
             plot, <line_type> and <point_type> may be specified.
             These are positive integer constants (or expressions) that
             specify the line type and point type to be used for the
             plot.  Use tteesstt to display the types available for your
             terminal.

             You may also scale the line width and point size for a
             plot by using <line_width> and <point_size>, which are
             specified relative to the default values for each termi-
             nal.  The pointsize may also be altered globally---see sseett
             ppooiinnttssiizzee for details.  But note that both <point_size> as
             set here and  as set by sseett ppooiinnttssiizzee multiply the default
             point size---their effects are  not cumulative.  That is,
             sseett ppooiinnttssiizzee 22;; pplloott xx ww pp ppss 33 will use points three
             times default size, not six.

             It is also possible to specify ppooiinnttssiizzee vvaarriiaabbllee either
             as part of a line style or for an individual plot. In this
             case one extra column of input is required, i.e. 3 columns
             for a 2D plot and 4 columns for a 3D splot. The size of
             each individual point is determined by multiplying the
             global pointsize by the value read from the data file.

             If you have defined specific line type/width and point
             type/size combinations with sseett ssttyyllee lliinnee, one of these
             may be selected by setting <line_style> to the index of
             the desired style.

             If gnuplot was built with ppmm33dd support, the special key-
             word ppaalleettttee is allowed for smooth color change of lines,
             points and dots in sspplloottss. The color is chosen from a
             smooth palette which was set previously with the command
             sseett ppaalleettttee. The color value corresponds to the z-value of
             the point coordinates or to the color coordinate if










   GNUPLOT 4.1                                                      124


             specified by the 4th parameter in uussiinngg. Both 2D and 3D
             plots (pplloott and sspplloott commands) can use palette colors as
             specified by either their fractional value or the corre-
             sponding value mapped to the colorbox range.  A palette
             color value can also be read from an explicitly specified
             input column in the uussiinngg specifier.  See ccoolloorrss, sseett
             ppaalleettttee, lliinneettyyppee.

             The keyword nnoohhiiddddeenn33dd applies only to plots made with the
             sspplloott command.  Normally the global option sseett hhiiddddeenn33dd
             applies to all plots in the graph.  You can attach the
             nnoohhiiddddeenn33dd option to any individual plots that you want to
             exclude from the hidden3d processing.  The individual ele-
             ments other than surfaces (i.e. lines, dots, labels, ...)
             of a plot marked nnoohhiiddddeenn33dd will all be drawn, even if
             they would normally be obscured by other plot elements.

             Similarly, the keyword nnooccoonnttoouurrss will turn off contouring
             for an individual plot even if the global property sseett
             ccoonnttoouurr is active.

             Similarly, the keyword nnoossuurrffaaccee will turn off the 3D sur-
             face for an individual plot even if the global property
             sseett ssuurrffaaccee is active.

             The keywords may be abbreviated as indicated.

             Note that the lliinneewwiiddtthh, ppooiinnttssiizzee and ppaalleettttee options are
             not supported by all terminals.

             Examples:

             This plots sin(x) with impulses:
                   plot sin(x) with impulses

             This plots x with points, x**2 with the default:
                   plot x w points, x**2

             This plots tan(x) with the default function style, file
             "data.1" with lines:
                   plot [ ] [-2:5] tan(x), 'data.1' with l

             This plots "leastsq.dat" with impulses:
                   plot 'leastsq.dat' w i

             This plots the data file "population" with boxes:
                   plot 'population' with boxes

             This plots "exper.dat" with errorbars and lines connecting
             the points (errorbars require three or four columns):
                   plot 'exper.dat' w lines, 'exper.dat' notitle w
             errorbars











   GNUPLOT 4.1                                                      125


             Another way to plot "exper.dat" with errorlines (errorbars
             require three or four columns):
                   plot 'exper.dat' w errorlines

             This plots sin(x) and cos(x) with linespoints, using the
             same line type but different point types:
                   plot sin(x) with linesp lt 1 pt 3, cos(x) with
             linesp lt 1 pt 4

             This plots file "data" with points of type 3 and twice
             usual size:
                   plot 'data' with points pointtype 3 pointsize 2

             This plots file "data" with variable pointsize read from
             column 4
                   plot 'data' using 1:2:4 with points pt 5 pointsize
             variable

             This plots two data sets with lines differing only by
             weight:
                   plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l
             lt 2 lw 1

             This plots filled curve of x*x and a color stripe:
                   plot x*x with filledcurve closed, 40 with filled-
             curve y1=10

             This plots x*x and a color box:
                   plot x*x, (x>=-5 && x<=5 ? 40 : 1/0) with filled-
             curve y1=10 lt 8

             This plots a surface with color lines:
                   splot x*x-y*y with line palette

             This plots two color surfaces at different altitudes:
                   splot x*x-y*y with pm3d, x*x+y*y with pm3d at t




        7755..  PPrriinntt


        The pprriinntt command prints the value of <expression> to the
        screen.  It is synonymous with ppaauussee 00.  <expression> may be
        anything that ggnnuupplloott can evaluate that produces a number, or
        it can be a string.

        Syntax:
              print <expression> {, <expression>, ...}

        See eexxpprreessssiioonnss.  The output file can be set with sseett pprriinntt.











   GNUPLOT 4.1                                                      126


        7766..  PPwwdd


        The ppwwdd command prints the name of the working directory to the
        screen.

        Note that if you wish to store the current directory into a
        string variable or use it in string expressions, then you can
        use variable GPVAL_PWD, see sshhooww vvaarriiaabblleess aallll.



        7777..  QQuuiitt


        The eexxiitt and qquuiitt commands and END-OF-FILE character will exit
        ggnnuupplloott.  Each of these commands will clear the output device
        (as does the cclleeaarr command) before exiting.



        7788..  RRaaiissee


        Syntax:
              raise {plot_window_nb}

        The rraaiissee command raises (opposite to lloowweerr) plot window(s)
        associated with the interactive terminal of your gnuplot ses-
        sion, i.e. ppmm, wwiinn, wwxxtt or xx1111. It puts the plot window to
        front (top) in the z-order windows stack of the window manager
        of your desktop.

        As xx1111 and wwxxtt support multiple plot windows, then by default
        they raise these windows in descending order of most recently
        created on top to the least recently created on bottom. If a
        plot number is supplied as an optional parameter, only the
        associated plot window will be raised if it exists.

        The optional parameter is ignored for single plot-windows ter-
        minal, i.e. ppmm and wwiinn.

        If the window is not raised under X11, then perhaps the plot
        window is running in a different X11 session (telnet or ssh
        session, for example), or perhaps raising is blocked by your
        window manager policy setting.



        7799..  RReeffrreesshh













   GNUPLOT 4.1                                                      127


        The rreeffrreesshh command is similar to rreepplloott, with two major dif-
        ferences.  rreeffrreesshh reformats and redraws the current plot using
        the data already read in. This means that you can use rreeffrreesshh
        for plots with in-line data (pseudo-device '-') and for plots
        from datafiles whose contents are volatile.  You cannot use the
        rreeffrreesshh command to add new data to an existing plot.

        Mousing operations, in particular zoom and unzoom, will use
        rreeffrreesshh rather than rreepplloott if appropriate.  Example:

              plot 'datafile' volatile with lines, '-' with labels
              100 200 "Special point"
              e
              # Various mousing operations go here
              set title "Zoomed in view"
              set term post
              set output 'zoom.ps'
              refresh




        8800..  RReepplloott


        The rreepplloott command without arguments repeats the last pplloott or
        sspplloott command.  This can be useful for viewing a plot with dif-
        ferent sseett options, or when generating the same plot for sev-
        eral devices.

        Arguments specified after a rreepplloott command will be added onto
        the last pplloott or sspplloott command (with an implied ',' separator)
        before it is repeated.  rreepplloott accepts the same arguments as
        the pplloott and sspplloott commands except that ranges cannot be speci-
        fied.  Thus you can use rreepplloott to plot a function against the
        second axes if the previous command was pplloott but not if it was
        sspplloott.

        N.B.---use of

              plot '-' ; ... ; replot

        is not recommended, because it will require that you type in
        the data all over again.  In most cases you can use the rreeffrreesshh
        command instead, which will redraw the plot using the data pre-
        viously read in.

        Note that rreepplloott does not work in mmuullttiipplloott mode, since it
        reproduces only the last plot rather than the entire screen.

        See also ccoommmmaanndd--lliinnee--eeddiittiinngg for ways to edit the last pplloott
        (sspplloott) command.











   GNUPLOT 4.1                                                      128


        See also sshhooww pplloott to show the whole current plotting command,
        and the possibility to copy it into the hhiissttoorryy.



        8811..  RReerreeaadd


        The rreerreeaadd command causes the current ggnnuupplloott command file, as
        specified by a llooaadd command or on the command line, to be reset
        to its starting point before further commands are read from it.
        This essentially implements an endless loop of the commands
        from the beginning of the command file to the rreerreeaadd command.
        (But this is not necessarily a disaster---rreerreeaadd can be very
        useful when used in conjunction with iiff.)  The rreerreeaadd command
        has no effect if input from standard input.

        Examples:

        Suppose the file "looper" contains the commands
              a=a+1
              plot sin(x*a)
              pause -1
              if(a<5) reread
        and from within ggnnuupplloott you submit the commands
              a=0
              load 'looper'
        The result will be five plots (separated by the ppaauussee message).

        Suppose the file "data" contains six columns of numbers with a
        total yrange from 0 to 10; the first is x and the next are five
        different functions of x.  Suppose also that the file "plotter"
        contains the commands
              c_p = c_p+1
              plot "$0" using 1:c_p with lines linetype c_p
              if(c_p <  n_p) reread
        and from within ggnnuupplloott you submit the commands
              n_p=6
              c_p=1
              unset key
              set yrange [0:10]
              set multiplot
              call 'plotter' 'data'
              unset multiplot
        The result is a single graph consisting of five plots.  The
        yrange must be set explicitly to guarantee that the five sepa-
        rate graphs (drawn on top of each other in multiplot mode) will
        have exactly the same axes.  The linetype must be specified;
        otherwise all the plots would be drawn with the same type.  See
        animate.dem in demo directory for an animated example.













   GNUPLOT 4.1                                                      129


        8822..  RReesseett


        The rreesseett command causes all graph-related options that can be
        set with the sseett command to take on their default values.  This
        command is useful, e.g., to restore the default graph settings
        at the end of a command file, or to return to a defined state
        after lots of settings have been changed within a command file.
        Please refer to the sseett command to see the default values that
        the various options take.

        The following are _not_ affected by rreesseett.
             `set term` `set output` `set loadpath` `set fontpath` `set
        linetype`
             `set encoding` `set decimalsign` `set locale` `set psdir`

        rreesseett eerrrroorrss clears only the error state variables GPVAL_ERRNO
        and GPVAL_ERRMSG.

        rreesseett bbiinndd restores all hotkey bindings to their default state.



        8833..  SSaavvee


        The ssaavvee command saves user-defined functions, variables, the
        sseett tteerrmm status, all sseett options, or all of these, plus the
        last pplloott (sspplloott) command to the specified file.

        Syntax:
              save  {<option>} '<filename>'

        where <option> is ffuunnccttiioonnss, vvaarriiaabblleess, tteerrmmiinnaall or sseett. If no
        option is used, ggnnuupplloott saves functions, variables, sseett options
        and the last pplloott (sspplloott) command.

        ssaavveed files are written in text format and may be read by the
        llooaadd command. For ssaavvee with the sseett option or without any
        option, the tteerrmmiinnaall choice and the oouuttppuutt filename are written
        out as a comment, to get an output file that works in other
        installations of gnuplot, without changes and without risk of
        unwillingly overwriting files.

        ssaavvee tteerrmmiinnaall will write out just the tteerrmmiinnaall status, without
        the comment marker in front of it. This is mainly useful for
        switching the tteerrmmiinnaall setting for a short while, and getting
        back to the previously set terminal, afterwards, by loading the
        saved tteerrmmiinnaall status. Note that for a single gnuplot session
        you may rather use the other method of saving and restoring
        current terminal by the commands sseett tteerrmm ppuusshh and sseett tteerrmm
        ppoopp, see sseett tteerrmm.











   GNUPLOT 4.1                                                      130


        The filename must be enclosed in quotes.

        The special filename "-" may be used to ssaavvee commands to stan-
        dard output.  On systems which support a popen function (Unix),
        the output of save can be piped through an external program by
        starting the file name with a '|'.  This provides a consistent
        interface to ggnnuupplloott's internal settings to programs which com-
        municate with ggnnuupplloott through a pipe.  Please see help for
        bbaattcchh//iinntteerraaccttiivvee for more details.

        Examples:
              save 'work.gnu'
              save functions 'func.dat'
              save var 'var.dat'
              save set 'options.dat'
              save term 'myterm.gnu'
              save '-'
              save '|grep title >t.gp'



        8844..  SSeett--sshhooww


        The sseett command can be used to set _lots_ of options.  No
        screen is drawn, however, until a pplloott, sspplloott, or rreepplloott com-
        mand is given.

        The sshhooww command shows their settings;  sshhooww aallll shows all the
        settings.

        Options changed using sseett can be returned to the default state
        by giving the corresponding uunnsseett command.  See also the rreesseett
        command, which returns all settable parameters to default val-
        ues.

        If a variable contains time/date data, sshhooww will display it
        according to the format currently defined by sseett ttiimmeeffmmtt, even
        if that was not in effect when the variable was initially
        defined.  The sseett and uunnsseett commands may optionally contain an
        iteration clause.  See iitteerraattiioonn.





             8844..11..  AAnngglleess


             By default, ggnnuupplloott assumes the independent variable in
             polar graphs is in units of radians.  If sseett aanngglleess
             ddeeggrreeeess is specified before sseett ppoollaarr, then the default
             range is [0:360] and the independent variable has units of










   GNUPLOT 4.1                                                      131


             degrees.  This is particularly useful for plots of data
             files.  The angle setting also applies to 3D mapping as
             set via the sseett mmaappppiinngg command.

             Syntax:
                   set angles {degrees | radians}
                   show angles

             The angle specified in sseett ggrriidd ppoollaarr is also read and
             displayed in the units specified by sseett aanngglleess.

             sseett aanngglleess also affects the arguments of the machine-
             defined functions sin(x), cos(x) and tan(x), and the out-
             puts of asin(x), acos(x), atan(x), atan2(x), and arg(x).
             It has no effect on the arguments of hyperbolic functions
             or Bessel functions.  However, the output arguments of
             inverse hyperbolic functions of complex arguments are
             affected; if these functions are used, sseett aanngglleess rraaddiiaannss
             must be in effect to maintain consistency between input
             and output arguments.

                   x={1.0,0.1}
                   set angles radians
                   y=sinh(x)
                   print y         #prints {1.16933, 0.154051}
                   print asinh(y)  #prints {1.0, 0.1}
             but
                   set angles degrees
                   y=sinh(x)
                   print y         #prints {1.16933, 0.154051}
                   print asinh(y)  #prints {57.29578, 5.729578}
             See also poldat.dem: polar plot using sseett aanngglleess demo.



             8844..22..  AArrrrooww


             Arbitrary arrows can be placed on a plot using the sseett
             aarrrrooww command.

             Syntax:
                   set arrow {<tag>} {from <position>} {to|rto <posi-
             tion>}
                             { {arrowstyle | as <arrow_style>}
                               | { {nohead | head | backhead | heads}
                                   {size <length>,<angle>{,<backan-
             gle>}}
                                   {filled | empty | nofilled}
                                   {front | back}
                                   { {linestyle | ls <line_style>}
                                     | {linetype | lt <line_type>}
                                       {linewidth | lw <line_width} } }










   GNUPLOT 4.1                                                      132


             }

                   unset arrow {<tag>}
                   show arrow {<tag>}

             <tag> is an integer that identifies the arrow.  If no tag
             is given, the lowest unused tag value is assigned automat-
             ically.  The tag can be used to delete or change a spe-
             cific arrow.  To change any attribute of an existing
             arrow, use the sseett aarrrrooww command with the appropriate tag
             and specify the parts of the arrow to be changed.

             The <position>s are specified by either x,y or x,y,z, and
             may be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarr--
             aacctteerr to select the coordinate system.  Unspecified coor-
             dinates default to 0.  The end points can be specified in
             one of five coordinate systems---ffiirrsstt or sseeccoonndd axes,
             ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr.  See ccoooorrddiinnaatteess for details.
             A coordinate system specifier does not carry over from the
             "from" position to the "to" position.  Arrows outside the
             screen boundaries are permitted but may cause device
             errors.  If the end point is specified by "rto" instead of
             "to" it is drawn relatively to the start point.  For lin-
             ear axes, ggrraapphh and ssccrreeeenn coordinates, the distance
             between the start and the end point corresponds to the
             given relative coordinate.  For logarithmic axes, the rel-
             ative given coordinate corresponds to the factor of the
             coordinate between start and end point.  Thus, a negative
             relative value or zero are not allowed for logarithmic
             axes.

             Specifying nnoohheeaadd produces an arrow drawn without a
             head---a line segment.  This gives you yet another way to
             draw a line segment on the plot.  By default, an arrow has
             a head at its end. Specifying bbaacckkhheeaadd draws an arrow head
             at the start point of the arrow while hheeaaddss draws arrow
             heads on both ends of the line.  Not all terminal types
             support double-ended arrows.

             Head size can be controlled by ssiizzee <<lleennggtthh>>,,<<aannggllee>> or
             ssiizzee <<lleennggtthh>>,,<<aannggllee>>,,<<bbaacckkaannggllee>>, where <<lleennggtthh>> defines
             length of each branch of the arrow head and <<aannggllee>> the
             angle (in degrees) they make with the arrow.  <<LLeennggtthh>> is
             in x-axis units; this can be changed by ffiirrsstt, sseeccoonndd,
             ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr before the <length>;  see
             ccoooorrddiinnaatteess for details.  <<BBaacckkaannggllee>> only takes effect
             when ffiilllleedd or eemmppttyy is also used.  Then, <<bbaacckkaannggllee>> is
             the angle (in degrees) the back branches make with the
             arrow (in the same direction as <<aannggllee>>).  The ffiigg termi-
             nal has a restricted backangle function. It supports three
             different angles. There are two thresholds: Below 70
             degrees, the arrow head gets an indented back angle. Above
             110 degrees, the arrow head has an acute back angle.










   GNUPLOT 4.1                                                      133


             Between these thresholds, the back line is straight.

             Specifying ffiilllleedd produces filled arrow heads (if heads
             are used).  Filling is supported on filled-polygon capable
             terminals, see help of ppmm33dd for their list, otherwise the
             arrow heads are closed but not filled.  The same result
             (closed but not filled arrow head) is reached by specify-
             ing eemmppttyy.  Further, filling and outline is obviously not
             supported on terminals drawing arrows by their own spe-
             cific routines, like mmeettaaffoonntt, mmeettaappoosstt, llaatteexx or ttggiiff.

             The line style may be selected from a user-defined list of
             line styles (see sseett ssttyyllee lliinnee) or may be defined here by
             providing values for <line_type> (an index from the
             default list of styles) and/or <line_width> (which is a
             multiplier for the default width).

             Note, however, that if a user-defined line style has been
             selected, its properties (type and width) cannot be
             altered merely by issuing another sseett aarrrrooww command with
             the appropriate index and lltt or llww.

             If ffrroonntt is given, the arrow is written on top of the
             graphed data. If bbaacckk is given (the default), the arrow is
             written underneath the graphed data.  Using ffrroonntt will
             prevent an arrow from being obscured by dense data.

             Examples:

             To set an arrow pointing from the origin to (1,2) with
             user-defined style 5, use:
                   set arrow to 1,2 ls 5

             To set an arrow from bottom left of plotting area to
             (-5,5,3), and tag the arrow number 3, use:
                   set arrow 3 from graph 0,0 to -5,5,3

             To change the preceding arrow to end at 1,1,1, without an
             arrow head and double its width, use:
                   set arrow 3 to 1,1,1 nohead lw 2

             To draw a vertical line from the bottom to the top of the
             graph at x=3, use:
                   set arrow from 3, graph 0 to 3, graph 1 nohead

             To draw a vertical arrow with T-shape ends, use:
                   set arrow 3 from 0,-5 to 0,5 heads size screen
             0.1,90

             To draw an arrow relatively to the start point, where the
             relative distances are given in graph coordinates, use:
                   set arrow from 0,-5 rto graph 0.1,0.1











   GNUPLOT 4.1                                                      134


             To draw an arrow with relative end point in logarithmic x
             axis, use:
                   set logscale x
                   set arrow from 100,-5 rto 10,10
             This draws an arrow from 100,-5 to 1000,5. For the loga-
             rithmic x axis, the relative coordinate 10 means "factor
             10" while for the linear y axis, the relative coordinate
             10 means "difference 10".

             To delete arrow number 2, use:
                   unset arrow 2

             To delete all arrows, use:
                   unset arrow

             To show all arrows (in tag order), use:
                   show arrow

             arrows demos.




             8844..33..  AAuuttoossccaallee


             Autoscaling may be set individually on the x, y or z axis
             or globally on all axes. The default is to autoscale all
             axes.  If you want to autoscale based on a subset of the
             plots in the figure, you can mark the other ones with the
             flag nnooaauuttoossccaallee.  See ddaattaaffiillee.

             Syntax:
                   set autoscale {<axes>{|min|max|fixmin|fixmax|fix} |
             fix | keepfix}
                   unset autoscale {<axes>}
                   show autoscale

             where <axes> is either xx, yy, zz, ccbb, xx22, yy22 or xxyy.  A key-
             word with mmiinn or mmaaxx appended (this cannot be done with
             xxyy) tells ggnnuupplloott to autoscale just the minimum or maximum
             of that axis.  If no keyword is given, all axes are
             autoscaled.

             A keyword with ffiixxmmiinn, ffiixxmmaaxx or ffiixx appended tells gnu-
             plot to disable extension of the axis range to the next
             tic mark position, for autoscaled axes using equidistant
             tics; sseett aauuttoossccaallee ffiixx sets this for all axes.  Command
             sseett aauuttoossccaallee kkeeeeppffiixx autoscales all axes while keeping
             the fix settings.

             When autoscaling, the axis range is automatically computed
             and the dependent axis (y for a pplloott and z for sspplloott) is










   GNUPLOT 4.1                                                      135


             scaled to include the range of the function or data being
             plotted.

             If autoscaling of the dependent axis (y or z) is not set,
             the current y or z range is used.

             Autoscaling the independent variables (x for pplloott and x,y
             for sspplloott) is a request to set the domain to match any
             data file being plotted.  If there are no data files,
             autoscaling an independent variable has no effect.  In
             other words, in the absence of a data file, functions
             alone do not affect the x range (or the y range if plot-
             ting z = f(x,y)).

             Please see sseett xxrraannggee for additional information about
             ranges.

             The behavior of autoscaling remains consistent in paramet-
             ric mode, (see sseett ppaarraammeettrriicc).  However, there are more
             dependent variables and hence more control over x, y, and
             z axis scales.  In parametric mode, the independent or
             dummy variable is t for ppllootts and u,v for ssppllootts.
             aauuttoossccaallee in parametric mode, then, controls all ranges
             (t, u, v, x, y, and z) and allows x, y, and z to be fully
             autoscaled.

             Autoscaling works the same way for polar mode as it does
             for parametric mode for pplloott, with the extension that in
             polar mode sseett dduummmmyy can be used to change the independent
             variable from t (see sseett dduummmmyy).

             When tics are displayed on second axes but no plot has
             been specified for those axes, x2range and y2range are
             inherited from xrange and yrange.  This is done _before_
             xrange and yrange are autoextended to a whole number of
             tics, which can cause unexpected results.  You can use the
             ffiixxmmiinn or ffiixxmmaaxx options to avoid this.

             Examples:

             This sets autoscaling of the y axis (other axes are not
             affected):
                   set autoscale y

             This sets autoscaling only for the minimum of the y axis
             (the maximum of the y axis and the other axes are not
             affected):
                   set autoscale ymin

             This disables extension of the x2 axis tics to the next
             tic mark, thus keeping the exact range as found in the
             plotted data and functions:
                   set autoscale x2fixmin










   GNUPLOT 4.1                                                      136


                   set autoscale x2fixmax

             This sets autoscaling of the x and y axes:
                   set autoscale xy

             This sets autoscaling of the x, y, z, x2 and y2 axes:
                   set autoscale

             This disables autoscaling of the x, y, z, x2 and y2 axes:
                   unset autoscale

             This disables autoscaling of the z axis only:
                   unset autoscale z




                  8844..33..11..  PPaarraammeettrriicc mmooddee


                  When in parametric mode (sseett ppaarraammeettrriicc), the xrange
                  is as fully scalable as the y range.  In other words,
                  in parametric mode the x axis can be automatically
                  scaled to fit the range of the parametric function
                  that is being plotted.  Of course, the y axis can
                  also be automatically scaled just as in the non-para-
                  metric case.  If autoscaling on the x axis is not
                  set, the current x range is used.

                  Data files are plotted the same in parametric and
                  non-parametric mode.  However, there is a difference
                  in mixed function and data plots: in non-parametric
                  mode with autoscaled x, the x range of the datafile
                  controls the x range of the functions; in parametric
                  mode it has no influence.

                  For completeness a last command sseett aauuttoossccaallee tt is
                  accepted.  However, the effect of this "scaling" is
                  very minor.  When ggnnuupplloott determines that the t range
                  would be empty, it makes a small adjustment if
                  autoscaling is true.  Otherwise, ggnnuupplloott gives an
                  error.  Such behavior may, in fact, not be very use-
                  ful and the command sseett aauuttoossccaallee tt is certainly
                  questionable.

                  sspplloott extends the above ideas as you would expect.
                  If autoscaling is set, then x, y, and z ranges are
                  computed and each axis scaled to fit the resulting
                  data.














   GNUPLOT 4.1                                                      137


                  8844..33..22..  PPoollaarr mmooddee


                  When in polar mode (sseett ppoollaarr), the xrange and the
                  yrange may be left in autoscale mode.  If sseett rrrraannggee
                  is used to limit the extent of the polar axis, then
                  xrange and yrange will adjust to match this automati-
                  cally.  However, explicit xrange and yrange commands
                  can later be used to make further adjustments.  See
                  sseett rrrraannggee.  The trange may also be autoscaled.  Note
                  that if the trange is contained within one quadrant,
                  autoscaling will produce a polar plot of only that
                  single quadrant.

                  Explicitly setting one or two ranges but not others
                  may lead to unexpected results.  See also polar
                  demos.



             8844..44..  BBaarrss


             The sseett bbaarrss command controls the tics at the ends of
             error bars, and also at the end of the whiskers belonging
             to a boxplot.

             Syntax:
                   set bars {small | large | fullwidth | <size>} {front
             | back}
                   unset bars
                   show bars

             ssmmaallll is a synonym for 0.0, and llaarrggee for 1.0.  The
             default is 1.0 if no size is given.

             The keyword ffuullllwwiiddtthh is relevant only to boxplots and to
             histograms with errorbars.  It sets the width of the
             errorbar ends to be the same as the width of the associ-
             ated box.  It does not change the width of the box itself.

             The ffrroonntt and bbaacckk keywords are relevant only to errorbars
             attached to filled rectangles (boxes, candlesticks, his-
             tograms).



             8844..55..  BBiinndd


             Show the current state of all hotkey bindings. See bbiinndd.












   GNUPLOT 4.1                                                      138


             8844..66..  BBmmaarrggiinn


             The command sseett bbmmaarrggiinn sets the size of the bottom mar-
             gin.  Please see sseett mmaarrggiinn for details.



             8844..77..  BBoorrddeerr


             The sseett bboorrddeerr and uunnsseett bboorrddeerr commands control the dis-
             play of the graph borders for the pplloott and sspplloott commands.
             Note that the borders do not necessarily coincide with the
             axes; with pplloott they often do, but with sspplloott they usually
             do not.

             Syntax:
                   set border {<integer>} {front | back} {linewidth |
             lw <line_width>}
                              {{linestyle | ls <line_style>} | {line-
             type | lt <line_type>}}
                   unset border
                   show border

             With a sspplloott displayed in an arbitrary orientation, like
             sseett vviieeww 5566,,110033, the four corners of the x-y plane can be
             referred to as "front", "back", "left" and "right".  A
             similar set of four corners exist for the top surface, of
             course.  Thus the border connecting, say, the back and
             right corners of the x-y plane is the "bottom right back"
             border, and the border connecting the top and bottom front
             corners is the "front vertical".  (This nomenclature is
             defined solely to allow the reader to figure out the table
             that follows.)

             The borders are encoded in a 12-bit integer: the bottom
             four bits control the border for pplloott and the sides of the
             base for sspplloott; the next four bits control the verticals
             in sspplloott; the top four bits control the edges on top of
             the sspplloott.  In detail, <<iinntteeggeerr>> should be the sum of the
             appropriate entries from the following table:





















   GNUPLOT 4.1                                                      139


                 +--------------------------------------+
                 |Bit      plot            splot        |
                 +--------------------------------------+
                 | 1      bottom     bottom left front  |
                 | 2       left       bottom left back  |
                 | 4        top      bottom right front |
                 | 8       right     bottom right back  |
                 | 16    no effect     left vertical    |
                 | 32    no effect     back vertical    |
                 | 64    no effect     right vertical   |
                 |128    no effect     front vertical   |
                 |256    no effect     top left back    |
                 |512    no effect     top right back   |
                 |1024   no effect     top left front   |
                 |2048   no effect    top right front   |
                 +--------------------------------------+




   Various bits or combinations of bits may be added together in the
   command.

   The default is 31, which is all four sides for pplloott, and base and z
   axis for sspplloott.

   In 2D plots the border is normally drawn on top of all plots ele-
   ments (ffrroonntt). If you want the border to be drawn behind the plot
   elements, use sseett bboorrddeerr bbaacckk.

   Using the optional <line_style>, <line_type> and <line_width> speci-
   fiers, the way the border lines are drawn can be influenced (limited
   by what the current terminal driver supports).

   For pplloott, tics may be drawn on edges other than bottom and left by
   enabling the second axes -- see sseett xxttiiccss for details.

   If a sspplloott draws only on the base, as is the case with "uunnsseett ssuurr--
   ffaaccee;; sseett ccoonnttoouurr bbaassee", then the verticals and the top are not
   drawn even if they are specified.

   The sseett ggrriidd options 'back', 'front' and 'layerdefault' also control
   the order in which the border lines are drawn with respect to the
   output of the plotted data.

   Examples:

   Draw default borders:
         set border

   Draw only the left and bottom (pplloott) or both front and back bottom
   left (sspplloott) borders:
         set border 3










   GNUPLOT 4.1                                                      140


   Draw a complete box around a sspplloott:
         set border 4095

   Draw a topless box around a sspplloott, omitting the front vertical:
         set border 127+256+512 # or set border 1023-128

   Draw only the top and right borders for a pplloott and label them as
   axes:
         unset xtics; unset ytics; set x2tics; set y2tics; set border
   12




             8844..88..  BBooxxwwiiddtthh


             The sseett bbooxxwwiiddtthh command is used to set the default width
             of boxes in the bbooxxeess, bbooxxeerrrroorrbbaarrss, bbooxxpplloott, ccaannddlleessttiicckkss
             and hhiissttooggrraammss styles.

             Syntax:
                   set boxwidth {<width>} {absolute|relative}
                   show boxwidth

             By default, adjacent boxes are extended in width until
             they touch each other.  A different default width may be
             specified using the sseett bbooxxwwiiddtthh command.  RReellaattiivvee widths
             are interpreted as being a fraction of this default width.

             An explicit value for the boxwidth is interpreted as being
             a number of units along the current x axis (aabbssoolluuttee)
             unless the modifier rreellaattiivvee is given.  If the x axis is a
             log-scale (see sseett lloogg) then the value of boxwidth is
             truly "absolute" only at x=1; this physical width is main-
             tained everywhere along the axis (i.e. the boxes do not
             become narrower the value of x increases). If the range
             spanned by a log scale x axis is far from x=1, some exper-
             imentation may be required to find a useful value of
             boxwidth.

             The default is superseded by explicit width information
             taken from an extra data column in styles bbooxxeess or bbooxxeerr--
             rroorrbbaarrss.  In a four-column data set, the fourth column
             will be interpreted as the box width unless the width is
             set to -2.0, in which case the width will be calculated
             automatically.  See ssttyyllee bbooxxeess and ssttyyllee bbooxxeerrrroorrbbaarrss for
             more details.

             To set the box width to automatic use the command
                   set boxwidth

             or, for four-column data,










   GNUPLOT 4.1                                                      141


                   set boxwidth -2

             The same effect can be achieved with the uussiinngg keyword in
             pplloott:
                   plot 'file' using 1:2:3:4:(-2)

             To set the box width to half of the automatic size use
                   set boxwidth 0.5 relative

             To set the box width to an absolute value of 2 use
                   set boxwidth 2 absolute



             8844..99..  CCllaabbeell


             ggnnuupplloott will vary the linetype used for each contour level
             when clabel is set.  When this option on (the default), a
             legend labels each linestyle with the z level it repre-
             sents.  It is not possible at present to separate the con-
             tour labels from the surface key.

             Syntax:
                   set clabel {'<format>'}
                   unset clabel
                   show clabel

             The default for the format string is %8.3g, which gives
             three decimal places.  This may produce poor label align-
             ment if the key is altered from its default configuration.

             The first contour linetype, or only contour linetype when
             clabel is off, is the surface linetype +1; contour points
             are the same style as surface points.

             See also sseett ccoonnttoouurr.



             8844..1100..  CClliipp


             ggnnuupplloott can clip data points and lines that are near the
             boundaries of a graph.

             Syntax:
                   set clip <clip-type>
                   unset clip <clip-type>
                   show clip

             Three clip types for points and lines are supported by
             ggnnuupplloott: ppooiinnttss, oonnee, and ttwwoo. One, two, or all three clip










   GNUPLOT 4.1                                                      142


             types may be active for a single graph.  Note that clip-
             ping of color filled quadrangles drawn by ppmm33dd maps and
             surfaces is not controlled by this command, but by sseett
             ppmm33dd cclliipp11iinn and sseett ppmm33dd cclliipp44iinn.

             The ppooiinnttss clip type forces ggnnuupplloott to clip (actually, not
             plot at all) data points that fall within but too close to
             the boundaries.  This is done so that large symbols used
             for points will not extend outside the boundary lines.
             Without clipping points near the boundaries, the plot may
             look bad.  Adjusting the x and y ranges may give similar
             results.

             Setting the oonnee clip type causes ggnnuupplloott to draw a line
             segment which has only one of its two endpoints within the
             graph.  Only the in-range portion of the line is drawn.
             The alternative is to not draw any portion of the line
             segment.

             Some lines may have both endpoints out of range, but pass
             through the graph.  Setting the ttwwoo clip-type allows the
             visible portion of these lines to be drawn.

             In no case is a line drawn outside the graph.

             The defaults are nnoocclliipp ppooiinnttss, cclliipp oonnee, and nnoocclliipp ttwwoo.

             To check the state of all forms of clipping, use
                   show clip

             For backward compatibility with older versions, the fol-
             lowing forms are also permitted:
                   set clip
                   unset clip

             sseett cclliipp is synonymous with sseett cclliipp ppooiinnttss; uunnsseett cclliipp
             turns off all three types of clipping.



             8844..1111..  CCnnttrrppaarraamm


             sseett ccnnttrrppaarraamm controls the generation of contours and
             their smoothness for a contour plot. sshhooww ccoonnttoouurr displays
             current settings of ccnnttrrppaarraamm as well as ccoonnttoouurr.

             Syntax:
                   set cntrparam { { linear
                                   | cubicspline
                                   | bspline
                                   | points <n>
                                   | order <n>










   GNUPLOT 4.1                                                      143


                                   | levels { auto {<n>} | <n>
                                              | discrete <z1>
             {,<z2>{,<z3>...}}
                                              | incremental <start>,
             <incr> {,<end>}
                                            }
                                   }
                                 }
                   show contour

             This command has two functions.  First, it sets the values
             of z for which contour points are to be determined (by
             linear interpolation between data points or function
             isosamples.)  Second, it controls the way contours are
             drawn between the points determined to be of equal z.  <n>
             should be an integral constant expression and <z1>, <z2>
             ... any constant expressions.  The parameters are:

             lliinneeaarr, ccuubbiiccsspplliinnee, bbsspplliinnee---Controls type of approxima-
             tion or interpolation.  If lliinneeaarr, then straight line seg-
             ments connect points of equal z magnitude.  If ccuubbiicc--
             sspplliinnee, then piecewise-linear contours are interpolated
             between the same equal z points to form somewhat smoother
             contours, but which may undulate.  If bbsspplliinnee, a guaran-
             teed-smoother curve is drawn, which only approximates the
             position of the points of equal-z.

             ppooiinnttss---Eventually all drawings are done with piecewise-
             linear strokes.  This number controls the number of line
             segments used to approximate the bbsspplliinnee or ccuubbiiccsspplliinnee
             curve.  Number of cubicspline or bspline segments
             (strokes) = ppooiinnttss * number of linear segments.

             oorrddeerr---Order of the bspline approximation to be used.
             The bigger this order is, the smoother the resulting con-
             tour.  (Of course, higher order bspline curves will move
             further away from the original piecewise linear data.)
             This option is relevant for bbsspplliinnee mode only.  Allowed
             values are integers in the range from 2 (linear) to 10.

             lleevveellss--- Selection of contour levels,  controlled by aauuttoo
             (default), ddiissccrreettee, iinnccrreemmeennttaall, and <n>, number of con-
             tour levels.

             For aauuttoo, <n> specifies a nominal number of levels; the
             actual number will be adjusted to give simple labels. If
             the surface is bounded by zmin and zmax, contours will be
             generated at integer multiples of dz between zmin and
             zmax, where dz is 1, 2, or 5 times some power of ten (like
             the step between two tic marks).

             For lleevveellss ddiissccrreettee, contours will be generated at z =
             <z1>, <z2> ... as specified; the number of discrete levels










   GNUPLOT 4.1                                                      144


             sets the number of contour levels.  In ddiissccrreettee mode, any
             sseett ccnnttrrppaarraamm lleevveellss <<nn>> are ignored.

             For iinnccrreemmeennttaall, contours are generated at values of z
             beginning at <start> and increasing by <increment>, until
             the number of contours is reached. <end> is used to deter-
             mine the number of contour levels, which will be changed
             by any subsequent sseett ccnnttrrppaarraamm lleevveellss <<nn>>.  If the z axis
             is logarithmic, <increment> will be interpreted as a fac-
             tor, just like in sseett zzttiiccss.

             If the command sseett ccnnttrrppaarraamm is given without any argu-
             ments specified,  the defaults are used: linear, 5 points,
             order 4, 5 auto levels.

             Examples:
                   set cntrparam bspline
                   set cntrparam points 7
                   set cntrparam order 10

             To select levels automatically, 5 if the level increment
             criteria are met:
                   set cntrparam levels auto 5

             To specify discrete levels at .1, .37, and .9:
                   set cntrparam levels discrete .1,1/exp(1),.9

             To specify levels from 0 to 4 with increment 1:
                   set cntrparam levels incremental  0,1,4

             To set the number of levels to 10 (changing an incremental
             end or possibly the number of auto levels):
                   set cntrparam levels 10

             To set the start and increment while retaining the number
             of levels:
                   set cntrparam levels incremental 100,50

             See also sseett ccoonnttoouurr for control of where the contours are
             drawn, and sseett ccllaabbeell for control of the format of the
             contour labels and linetypes.

             See also contours demo (contours.dem) and contours with
             user defined levels demo (discrete.dem).



             8844..1122..  CCoolloorr bbooxx



             The color scheme, i.e. the gradient of the smooth color
             with min_z and max_z values of ppmm33dd's ppaalleettttee, is drawn in










   GNUPLOT 4.1                                                      145


             a color box unless uunnsseett ccoolloorrbbooxx.

                   set colorbox
                   set colorbox {
                              { vertical | horizontal }
                              { default | user }
                              { origin x, y }
                              { size x, y }
                              { front | back }
                              { noborder | bdefault | border [line
             style] }
                            }
                   show colorbox
                   unset colorbox

             Color box position can be ddeeffaauulltt or uusseerr.  If the latter
             is specified the values as given with the oorriiggiinn and ssiizzee
             subcommands are used. The box can be drawn after (ffrroonntt)
             or before (bbaacckk) the graph or the surface.

             The orientation of the color gradient can be switched by
             options vveerrttiiccaall and hhoorriizzoonnttaall.

             oorriiggiinn xx,, yy and ssiizzee xx,, yy are used only in combination
             with the uusseerr option. The x and y values are interpreted
             as screen coordinates by default, and this is the only
             legal option for 3D plots. 2D plots, including splot with
             sseett vviieeww mmaapp, allow any coordinate system to be specified.
             Try for example:
                 set colorbox horiz user origin .1,.02 size .8,.04
             which will draw a horizontal gradient somewhere at the
             bottom of the graph.

             bboorrddeerr turns the border on (this is the default). nnoobboorrddeerr
             turns the border off. If an positive integer argument is
             given after bboorrddeerr, it is used as a line style tag which
             is used for drawing the border, e.g.:
                 set style line 2604 linetype -1 linewidth .4
                 set colorbox border 2604
             will use line style 22660044, a thin line with the default
             border color (-1) for drawing the border. bbddeeffaauulltt (which
             is the default) will use the default border line style for
             drawing the border of the color box.

             The axis of the color box is called ccbb and it is con-
             trolled by means of the usual axes commands, i.e.
             sseett//uunnsseett//sshhooww with ccbbrraannggee, [[mm]]ccbbttiiccss, ffoorrmmaatt ccbb, ggrriidd
             [[mm]]ccbb, ccbbllaabbeell, and perhaps even ccbbddaattaa, [[nnoo]]ccbbddttiiccss,
             [[nnoo]]ccbbmmttiiccss.

             sseett ccoolloorrbbooxx without any parameter switches the position
             to default.  uunnsseett ccoolloorrbbooxx resets the default parameters
             for the colorbox and switches the colorbox off.










   GNUPLOT 4.1                                                      146


             See also help for sseett ppmm33dd, sseett ppaalleettttee, xx1111 ppmm33dd, and sseett
             ssttyyllee lliinnee.



             8844..1133..  CCoolloorrnnaammeess


             Gnuplot knows a limited number of color names. You can use
             these to define the color range spanned by a pm3d palette,
             or to assign a terminal-independent color to a particular
             linetype or linestyle. To see the list of known color
             names, use the command sshhooww ccoolloorrnnaammeess.   Example:

                   set style line 1 linecolor rgb "sea-green"



             8844..1144..  CCoonnttoouurr


             sseett ccoonnttoouurr enables contour drawing for surfaces.  This
             option is available for sspplloott only.  It requires grid
             data, see ggrriidd__ddaattaa for more details.  If contours are
             desired from non-grid data, sseett ddggrriidd33dd can be used to
             create an appropriate grid.

             Syntax:
                   set contour {base | surface | both}
                   unset contour
                   show contour

             The three options specify where to draw the contours: bbaassee
             draws the contours on the grid base where the x/ytics are
             placed, ssuurrffaaccee draws the contours on the surfaces them-
             selves, and bbootthh draws the contours on both the base and
             the surface.  If no option is provided, the default is
             bbaassee.

             See also sseett ccnnttrrppaarraamm for the parameters that affect the
             drawing of contours, and sseett ccllaabbeell for control of
             labelling of the contours.

             The surface can be switched off (see sseett ssuurrffaaccee), giving
             a contour-only graph.  Though it is possible to use sseett
             ssiizzee to enlarge the plot to fill the screen, more control
             over the output format can be obtained by writing the con-
             tour information to a file, and rereading it as a 2D
             datafile plot:

                   unset surface
                   set contour
                   set cntrparam ...










   GNUPLOT 4.1                                                      147


                   set table 'filename'
                   splot ...
                   unset table
                   # contour info now in filename
                   set term <whatever>
                   plot 'filename'

             In order to draw contours, the data should be organized as
             "grid data".  In such a file all the points for a single
             y-isoline are listed, then all the points for the next y-
             isoline, and so on.  A single blank line (a line contain-
             ing no characters other than blank spaces and a carriage
             return and/or a line feed) separates one y-isoline from
             the next.  See also sspplloott ddaattaaffiillee.

             See also contours demo (contours.dem) and contours with
             user defined levels demo (discrete.dem).



             8844..1155..  DDaattaa ssttyyllee


             This form of the command is deprecated. Please see sseett
             ssttyyllee ddaattaa.



             8844..1166..  DDaattaaffiillee


             The sseett ddaattaaffiillee command options control interpretation of
             fields read from input data files by the pplloott, sspplloott, and
             ffiitt commands.  Six such options are currently implemented.




                  8844..1166..11..  SSeett ddaattaaffiillee ffoorrttrraann


                  The sseett ddaattaaffiillee ffoorrttrraann command enables a special
                  check for values in the input file expressed as For-
                  tran D or Q constants. This extra check slows down
                  the input process, and should only be selected if you
                  do in fact have datafiles containing Fortran D or Q
                  constants. The option can be disabled again using
                  uunnsseett ddaattaaffiillee ffoorrttrraann.















   GNUPLOT 4.1                                                      148


                  8844..1166..22..  SSeett ddaattaaffiillee nnooffppee__ttrraapp


                  The sseett ddaattaaffiillee nnooffppee__ttrraapp command tells gnuplot not
                  to re-initialize a floating point exception handler
                  before every expression evaluation used while reading
                  data from an input file.  This can significantly
                  speed data input from very large files at the risk of
                  program termination if a floating-point exception is
                  generated.



                  8844..1166..33..  SSeett ddaattaaffiillee mmiissssiinngg


                  The sseett ddaattaaffiillee mmiissssiinngg command allows you to tell
                  ggnnuupplloott what character string is used in a data file
                  to denote missing data.  Exactly how this missing
                  value will be treated depends on the uussiinngg specifier
                  of the pplloott or sspplloott command.

                  Syntax:
                        set datafile missing {"<string>"}
                        show datafile missing
                        unset datafile

                  Example:
                        # Ignore entries containing IEEE NaN ("Not a
                  Number") code
                        set datafile missing "NaN"

                  Example:
                        set style data linespoints
                        plot '-'
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e
                        set datafile missing "?"
                        plot '-'
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e
                        plot '-' using 1:2
                           1 10
                           2 20
                           3 ?










   GNUPLOT 4.1                                                      149


                           4 40
                           5 50
                           e
                        plot '-' using 1:($2)
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e

                  The first pplloott will recognize only the first datum in
                  the "3 ?" line.  It will use the single-datum-on-a-
                  line convention that the line number is "x" and the
                  datum is "y", so the point will be plotted (in this
                  case erroneously) at (2,3).

                  The second and third pplloott commands will correctly
                  ignore the middle line.  The plotted line will con-
                  nect the points at (2,20) and (4,40).

                  The fourth pplloott will also correctly ignore the middle
                  line, but the plotted line will not connect the
                  points at (2,20) and (4,40).

                  There is no default character for mmiissssiinngg, but in
                  many cases any non-parsible string of characters
                  found where a numerical value is expected will be
                  treated as missing data.




                  8844..1166..44..  SSeett ddaattaaffiillee sseeppaarraattoorr


                  The command sseett ddaattaaffiillee sseeppaarraattoorr ""<<cchhaarr>>"" tells
                  ggnnuupplloott that data fields in subsequent input files
                  are separated by <char> rather than by whitespace.
                  The most common use is to read in csv (comma-sepa-
                  rated value) files written by spreadsheet or database
                  programs. By default data fields are separated by
                  whitespace.

                  Syntax:
                        set datafile separator {"<char>" | whitespace}

                  Examples:
                        # Input file contains tab-separated fields
                        set datafile separator "\t"

                        # Input file contains comma-separated values
                  fields










   GNUPLOT 4.1                                                      150


                        set datafile separator ","



                  8844..1166..55..  SSeett ddaattaaffiillee ccoommmmeennttsscchhaarrss


                  The sseett ddaattaaffiillee ccoommmmeennttsscchhaarrss command allows you to
                  tell ggnnuupplloott what characters are used in a data file
                  to denote comments.  Gnuplot will ignore rest of the
                  line behind the specified characters if either of
                  them is the first non-blank character on the line.

                  Syntax:
                        set datafile commentschars {"<string>"}
                        show datafile commentschars
                        unset commentschars

                  Default value of the string is "#!" on VMS and "#"
                  otherwise.

                  Then, the following line in a data file is completely
                  ignored
                      # 1 2 3 4
                  but the following
                      1 # 3 4
                  produces rather unexpected plot unless
                      set datafile missing '#'
                  is specified as well.

                  Example:
                        set datafile commentschars "#!%"



                  8844..1166..66..  SSeett ddaattaaffiillee bbiinnaarryy


                  The sseett ddaattaaffiillee bbiinnaarryy command is used to set the
                  defaults when reading binary data files.  The syntax
                  matches precisely that used for commands pplloott and
                  sspplloott.  See bbiinnaarryy mmaattrriixx and bbiinnaarryy ggeenneerraall for
                  details about the keywords that can be present in
                  <binary list>.

                  Syntax:
                        set datafile binary <binary list>
                        show datafile binary
                        show datafile
                        unset datafile

                  Examples:
                        set datafile binary filetype=auto










   GNUPLOT 4.1                                                      151


                        set datafile binary array=(512,512) for-
                  mat="%uchar"

                        show datafile binary   # list current settings



             8844..1177..  DDeecciimmaallssiiggnn


             The sseett ddeecciimmaallssiiggnn command selects a decimal sign for
             numbers printed into tic labels or sseett llaabbeell strings.

             Syntax:
                   set decimalsign {<value> | locale {"<locale>"}}
                   unset decimalsign
                   show decimalsign

             The argument <value> is a string to be used in place of
             the usual decimal point. Typical choices include the
             period, '.', and the comma, ',', but others may be useful,
             too.  If you omit the <value> argument, the decimal sepa-
             rator is not modified from the usual default, which is a
             period.  Unsetting decimalsign has the same effect as
             omitting <value>.

             Example:

             Correct typesetting in most European countries requires:
                   set decimalsign ','

             Please note: If you set an explicit string, this affects
             only numbers that are printed using gnuplot's gprintf()
             formatting routine, include axis tics.  It does not affect
             the format expected for input data, and it does not affect
             numbers printed with the sprintf() formatting routine. To
             change the behavior of both input and output formatting,
             instead use the form

                   set decimalsign locale

             This instructs the program to use both input and output
             formats in accordance with the current setting of the
             LC_ALL, LC_NUMERIC, or LANG environmental variables.

                   set decimalsign locale "foo"

             This instructs the program to format all input and output
             in accordance with locale "foo", which must be installed.
             If locale "foo" is not found then an error message is
             printed and the decimal sign setting is unchanged.  On
             linux systems you can get a list of the locales installed
             on your machine by typing "locale -a". A typical linux










   GNUPLOT 4.1                                                      152


             locale string is of the form "sl_SI.UTF-8".  A typical
             Windows locale string is of the form "Slovenian_Slove-
             nia.1250" or "slovenian". Please note that interpretation
             of the locale settings is done by the C library at run-
             time. Older C libraries may offer only partial support for
             locale settings such as the thousands grouping separator
             character.

                   set decimalsign locale; set decimalsign "."

             This sets all input and output to use whatever decimal
             sign is correct for the current locale, but over-rides
             this with an explicit '.' in numbers formatted using gnu-
             plot's internal gprintf() function.



             8844..1188..  DDggrriidd33dd


             The sseett ddggrriidd33dd command enables, and can set parameters
             for, non-grid to grid data mapping.  See sspplloott ggrriidd__ddaattaa
             for more details about the grid data structure.

             Syntax:
                   set dgrid3d {<rows>} {,{<cols>}}
                               { splines |
                                 qnorm {<norm>} |
                                 (gauss | cauchy | exp | box | hann)
                                   {kdensity} {<dx>} {,<dy>} }
                   unset dgrid3d
                   show dgrid3d

             By default ddggrriidd33dd is disabled.  When enabled, 3D data
             read from a file are always treated as a scattered data
             set.  A grid with dimensions derived from a bounding box
             of the scattered data and size as specified by the
             row/col_size parameters is created for plotting and con-
             touring.  The grid is equally spaced in x (rows) and in y
             (columns); the z values are computed as weighted averages
             or spline interpolations of the scattered points' z val-
             ues. In other words, a regularly spaced grid is created
             and the a smooth approximation to the raw data is evalu-
             ated for all grid points. This approximation is plotted in
             place of the raw data.

             The number of columns defaults to the number of rows,
             which defaults to 10.

             Several algorithms are available to calculate the approxi-
             mation from the raw data. Some of these algorithms can
             take additional parameters.  These interpolations are such
             the closer the data point is to a grid point, the more










   GNUPLOT 4.1                                                      153


             effect it has on that grid point.

             The sspplliinneess algorithm calculates an interpolation based on
             "thin plate splines". It does not take additional parame-
             ters.

             The qqnnoorrmm algorithm calculates a weighted average of the
             input data at each grid point. Each data point is weighted
             inversely by its distance from the grid point raised to
             the norm power.  (Actually, the weights are given by the
             inverse of dx^norm + dy^norm, where dx and dy are the com-
             ponents of the separation of the grid point from each data
             point.  For some norms that are powers of two, specifi-
             cally 4, 8, and 16, the computation is optimized by using
             the Euclidean distance in the weight calculation,
             (dx^2+dy^2)^norm/2.  However, any non-negative integer can
             be used.)  The power of the norm can be specified as a
             single optional parameter.  This algorithm is the default.

             Finally, several smoothing kernels are available to calcu-
             late weighted averages: z = Sum_i w(d_i) * z_i / Sum_i
             w(d_i), where z_i is the value of the i-th data point and
             d_i is the distance between the current grid point and the
             location of the i-th data point. All kernels assign higher
             weights to data points that are close to the current grid
             point and lower weights to data points further away.

             The following kernels are available:
                   gauss :     w(d) = exp(-d*d)
                   cauchy :    w(d) = 1/(1 + d*d)
                   exp :       w(d) = exp(-d)
                   box :       w(d) = 1                     if d<1
                                    = 0                     otherwise
                   hann :      w(d) = 0.5*(1-cos(2*pi*d))   if d<1
                               w(d) = 0                     otherwise

             When using one of these five smoothing kernels, up to two
             additional numerical parameters can be specified: dx and
             dy. These are used to rescale the coordinate differences
             when calculating the distance: d_i = sqrt( ((x-x_i)/dx)**2
             + ((y-y_i)/dy)**2 ), where x,y are the coordinates of the
             current grid point and x_i,y_i are the coordinates of the
             i-th data point. The value of dy defaults to the value of
             dx, which defaults to 1. The parameters dx and dy make it
             possible to control the radius over which data points con-
             tribute to a grid point IN THE UNITS OF THE DATA ITSELF.

             The optional keyword kkddeennssiittyy22dd, which must come after the
             name of the kernel, but before the (optional) scale param-
             eters, modifies the algorithm so that the values calcu-
             lated for the grid points are not divided by the sum of
             the weights ( z = Sum_i w(d_i) * z_i ). If all z_i are
             constant, this effectively plots a bivariate kernel










   GNUPLOT 4.1                                                      154


             density estimate: a kernel function (one of the five
             defined above) is placed at each data point, the sum of
             these kernels is evaluated at every grid point, and this
             smooth surface is plotted instead of the original data.
             This is similar in principle to + what the ssmmooootthh kkddeennssiittyy
             option does to 1D datasets.  (See kdensity2d.dem for usage
             demo)

             A slightly different syntax is also supported for reasons
             of backwards compatibility. If no interpolation algorithm
             has been explicitly selected, the qqnnoorrmm algorithm is
             assumed. Up to three comma-separated, optional parameters
             can be specified, which are interpreted as the the number
             of rows, the number of columns, and the norm value,
             respectively.

             The ddggrriidd33dd option is a simple scheme which replaces scat-
             tered data with weighted averages on a regular grid.  More
             sophisticated approaches to this problem exist and should
             be used to preprocess the data outside ggnnuupplloott if this
             simple solution is found inadequate.

             See also dgrid3d.dem: dgrid3d demo.  and scatter.dem:
             dgrid3d demo.




             8844..1199..  DDuummmmyy


             The sseett dduummmmyy command changes the default dummy variable
             names.

             Syntax:
                   set dummy {<dummy-var>} {,<dummy-var>}
                   show dummy

             By default, ggnnuupplloott assumes that the independent, or
             "dummy", variable for the pplloott command is "t" if in para-
             metric or polar mode, or "x" otherwise.  Similarly the
             independent variables for the sspplloott command are "u" and
             "v" in parametric mode (sspplloott cannot be used in polar
             mode), or "x" and "y" otherwise.

             It may be more convenient to call a dummy variable by a
             more physically meaningful or conventional name.  For
             example, when plotting time functions:

                   set dummy t
                   plot sin(t), cos(t)

             At least one dummy variable must be set on the command;










   GNUPLOT 4.1                                                      155


             sseett dduummmmyy by itself will generate an error message.

             Examples:
                   set dummy u,v
                   set dummy ,s

             The second example sets the second variable to s.



             8844..2200..  EEnnccooddiinngg


             The sseett eennccooddiinngg command selects a character encoding.
             Syntax:
                   set encoding {<value>}
                   set encoding locale
                   show encoding

             Valid values are
                default     - tells a terminal to use its default
             encoding
                iso_8859_1  - the most common Western European encoding
             used by many
                              Unix workstations and by MS-Windows. This
             encoding is
                              known in the PostScript world as 'ISO-
             Latin1'.
                iso_8859_15 - a variant of iso_8859_1 that includes the
             Euro symbol
                iso_8859_2  - used in Central and Eastern Europe
                iso_8859_9  - used in Turkey (also known as Latin5)
                koi8r       - popular Unix cyrillic encoding
                koi8u       - ukrainian Unix cyrillic encoding
                cp437       - codepage for MS-DOS
                cp850       - codepage for OS/2, Western Europe
                cp852       - codepage for OS/2, Central and Eastern
             Europe
                cp950       - MS version of Big5 (emf terminal only)
                cp1250      - codepage for MS Windows, Central and
             Eastern Europe
                cp1251      - codepage for 8-bit Russian, Serbian, Bul-
             garian, Macedonian
                cp1254      - codepage for MS Windows, Turkish (super-
             set of Latin5)
                sjis        - shift-JIS Japanese encoding
                utf8        - variable-length (multibyte) representa-
             tion of Unicode
                              entry point for each character

             The command sseett eennccooddiinngg llooccaallee is different from the
             other options.  It attempts to determine the current
             locale from the runtime environment.  On most systems this










   GNUPLOT 4.1                                                      156


             is controlled by the environmental variables LC_ALL,
             LC_CTYPE, or LANG.  This mechanism is necessary, for exam-
             ple, to pass multibyte character encodings such as UTF-8
             or EUC_JP to the wxt and cairopdf terminals.  This command
             does not affect the locale-specific representation of
             dates or numbers.  See also sseett llooccaallee and sseett ddeecciimmaall--
             ssiiggnn.

             Generally you must set the encoding before setting the
             terminal type.  Note that encoding is not supported by all
             terminal drivers and that the device must be able to pro-
             duce the desired non-standard characters.



             8844..2211..  FFiitt


             The ffiitt setting defines where the ffiitt command writes its
             output.

             Syntax:
                   set fit {logfile {"<filename>"}} {{no}errorvari-
             ables} {{no}quiet}
                   unset fit
                   show fit

             The <filename> argument must be enclosed in single or dou-
             ble quotes.

             If no filename is given or uunnsseett ffiitt is used the log file
             is reset to its default value "fit.log" or the value of
             the environmental variable FFIITT__LLOOGG.

             If the given logfile name ends with a / or \, it is inter-
             preted to be a directory name, and the actual filename
             will be "fit.log" in that directory.

             If the eerrrroorrvvaarriiaabblleess option is turned on, the error of
             each fitted parameter computed by ffiitt will be copied to a
             user-defined variable whose name is formed by appending
             "_err" to the name of the parameter itself.  This is use-
             ful mainly to put the parameter and its error onto a plot
             of the data and the fitted function, for reference, as in:

                    set fit errorvariables
                    fit f(x) 'datafile' using 1:2 via a, b
                    print "error of a is:", a_err
                    set label 'a=%6.2f', a, '+/- %6.2f', a_err
                    plot 'datafile' using 1:2, f(x)

             By default the information written to the log file is also
             echoed to the terminal session. sseett ffiitt qquuiieett turns off










   GNUPLOT 4.1                                                      157


             the echo.



             8844..2222..  FFoonnttppaatthh


             The ffoonnttppaatthh setting defines additional locations for font
             files searched when including font files. Currently only
             the postscript terminal supports ffoonnttppaatthh. If a file can-
             not be found in the current directory, the directories in
             ffoonnttppaatthh are tried. Further documentation concerning the
             supported file formats is included in the tteerrmmiinnaall ppoosstt--
             ssccrriipptt section of the documentation.

             Syntax:
                   set fontpath {"pathlist1" {"pathlist2"...}}
                   show fontpath

             Path names may be entered as single directory names, or as
             a list of path names separated by a platform-specific path
             separator, eg. colon (':') on Unix, semicolon (';') on
             DOS/Windows/OS/2 platforms.  The sshhooww ffoonnttppaatthh, ssaavvee and
             ssaavvee sseett commands replace the platform-specific separator
             with a space character (' ') for maximum portability. If a
             directory name ends with an exclamation mark ('!') also
             the subdirectories of this directory are searched for font
             files.

             If the environmental variable GNUPLOT_FONTPATH is set, its
             contents are appended to ffoonnttppaatthh.  If it is not set, a
             system dependent default value is used. It is set by test-
             ing several directories for existence when using the font-
             path the first time. Thus, the first call of sseett ffoonnttppaatthh,
             sshhooww ffoonnttppaatthh, ssaavvee ffoonnttppaatthh, pplloott, or sspplloott with embedded
             font files takes a little more time. If you want to save
             this time you may set the environmental variable GNU-
             PLOT_FONTPATH since probing is switched off, then. You can
             find out which is the default fontpath by using sshhooww ffoonntt--
             ppaatthh.

             sshhooww ffoonnttppaatthh prints the contents of the user-defined
             fontpath and the system fontpath separately.  However, the
             ssaavvee and ssaavvee sseett commands save only the user-specified
             parts of ffoonnttppaatthh.

             For terminal drivers that access fonts by filename via the
             gd library, the font search path is controlled by the
             environmental variable GDFONTPATH.














   GNUPLOT 4.1                                                      158


             8844..2233..  FFoorrmmaatt


             The format of the tic-mark labels can be set with the sseett
             ffoorrmmaatt command or with the sseett ttiiccss ffoorrmmaatt or individual
             sseett {{aaxxiiss}}ttiiccss ffoorrmmaatt commands.

             Syntax:
                   set format {<axes>} {"<format-string>"}
                   set format {<axes>} {'<format-string>'}
                   show format

             where <axes> is either xx, yy, xxyy, xx22, yy22, zz, ccbb or nothing
             (which applies the format to all axes). The following two
             commands are equivalent:
                   set format y "%.2f"
                   set ytics format "%.2f"

             The length of the string is restricted to 100 characters.
             The default format is "% g", but other formats such as
             "%.2f" or "%3.0em" are often desirable.  The format "$%g$"
             is often desirable for LaTeX.  If no format string is
             given, the format will be returned to the default.  If the
             empty string "" is given, tics will have no labels,
             although the tic mark will still be plotted.  To eliminate
             the tic marks, use uunnsseett xxttiiccss or sseett ttiiccss ssccaallee 00.

             Newline (\n) and enhanced text markup is accepted in the
             format string.  Use double-quotes rather than single-
             quotes in this case.  See also ssyynnttaaxx.  Characters not
             preceded by "%" are printed verbatim.  Thus you can
             include spaces and labels in your format string, such as
             "%g m", which will put " m" after each number.  If you
             want "%" itself, double it: "%g %%".

             See also sseett xxttiiccss for more information about tic labels,
             and sseett ddeecciimmaallssiiggnn for how to use non-default decimal
             separators in numbers printed this way.  See also electron
             demo (electron.dem).




                  8844..2233..11..  GGpprriinnttff


                  The string function gprintf("format",x) uses gnu-
                  plot's own format specifiers, as do the gnuplot com-
                  mands sseett ffoorrmmaatt, sseett ttiimmeessttaammpp, and others. These
                  format specifiers are not the same as those used by
                  the standard C-language routine sprintf(). gprintf()
                  accepts only a single variable to be formatted.  Gnu-
                  plot also provides an sprintf("format",x1,x2,...)










   GNUPLOT 4.1                                                      159


                  routine if you prefer.  For a list of gnuplot's for-
                  mat options, see ffoorrmmaatt ssppeecciiffiieerrss.



                  8844..2233..22..  FFoorrmmaatt ssppeecciiffiieerrss


                  The acceptable formats (if not in time/date mode)
                  are:




   +-------------------------------------------------------------------------------+
   | Format    Explanation                                                         |
   +-------------------------------------------------------------------------------+
   |   %f      floating point notation                                             |
   |%e or %E   exponential notation; an "e" or "E" before the power                |
   |%g or %G   the shorter of %e (or %E) and %f                                    |
   |%x or %X   hex                                                                 |
   |%o or %O   octal                                                               |
   |   %t      mantissa to base 10                                                 |
   |   %l      mantissa to base of current logscale                                |
   |   %s      mantissa to base of current logscale; scientific power              |
   |   %T      power to base 10                                                    |
   |   %L      power to base of current logscale                                   |
   |   %S      scientific power                                                    |
   |   %c      character replacement for scientific power                          |
   |   %b      mantissa of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi) |
   |   %B      prefix of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi)   |
   |   %P      multiple of pi                                                      |
   +-------------------------------------------------------------------------------+
   +-------------------------------------------------------------------------------+




   A 'scientific' power is one such that the exponent is a multiple of
   three.  Character replacement of scientific powers (""%%cc"") has been
   implemented for powers in the range -18 to +18.  For numbers outside
   of this range the format reverts to exponential.

   Other acceptable modifiers (which come after the "%" but before the
   format specifier) are "-", which left-justifies the number; "+",
   which forces all numbers to be explicitly signed; " " (a space),
   which makes positive numbers have a space in front of them where
   negative numbers have "-"; "#", which places a decimal point after
   floats that have only zeroes following the decimal point; a positive
   integer, which defines the field width; "0" (the digit, not the let-
   ter) immediately preceding the field width, which indicates that
   leading zeroes are to be used instead of leading blanks; and a deci-
   mal point followed by a non-negative integer, which defines the










   GNUPLOT 4.1                                                      160


   precision (the minimum number of digits of an integer, or the number
   of digits following the decimal point of a float).

   Some systems may not support all of these modifiers but may also
   support others; in case of doubt, check the appropriate documenta-
   tion and then experiment.

   Examples:
         set format y "%t"; set ytics (5,10)          # "5.0" and "1.0"
         set format y "%s"; set ytics (500,1000)      # "500" and "1.0"
         set format y "%+-12.3f"; set ytics(12345)    # "+12345.000  "
         set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
         set format y "%s*10^{%S}"; set ytic(12345)   # "12.345*10^{3}"
         set format y "%s %cg"; set ytic(12345)       # "12.345 kg"
         set format y "%.0P pi"; set ytic(6.283185)   # "2 pi"
         set format y "%.0f%%"; set ytic(50)          # "50%"

         set log y 2; set format y '%l'; set ytics (1,2,3)
         #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)

   There are some problem cases that arise when numbers like 9.999 are
   printed with a format that requires both rounding and a power.

   If the data type for the axis is time/date, the format string must
   contain valid codes for the 'strftime' function (outside of ggnnuupplloott,
   type "man strftime").  See sseett ttiimmeeffmmtt for a list of the allowed
   input format codes.



                  8844..2233..33..  TTiimmee//ddaattee ssppeecciiffiieerrss


                  In time/date mode, the acceptable formats are:





























   GNUPLOT 4.1                                                      161


     +--------------------------------------------------------------+
     | Format    Explanation                                        |
     +--------------------------------------------------------------+
     |   %a      abbreviated name of day of the week                |
     |   %A      full name of day of the week                       |
     |%b or %h   abbreviated name of the month                      |
     |   %B      full name of the month                             |
     |   %d      day of the month, 01--31                           |
     |   %D      shorthand for "%m/%d/%y" (only output)             |
     |   %F      shorthand for "%Y-%m-%d" (only output)             |
     |   %k      hour, 0--23 (one or two digits)                    |
     |   %H      hour, 00--23 (always two digits)                   |
     |   %l      hour, 1--12 (one or two digits)                    |
     |   %I      hour, 01--12 (always two digits)                   |
     |   %j      day of the year, 1--366                            |
     |   %m      month, 01--12                                      |
     |   %M      minute, 0--60                                      |
     |   %p      "am" or "pm"                                       |
     |   %r      shorthand for "%I:%M:%S %p" (only output)          |
     |   %R      shorthand for %H:%M" (only output)                 |
     |   %S      second, integer 0--60 on output, (double) on input |
     |   %s      number of seconds since start of year 2000         |
     |   %T      shorthand for "%H:%M:%S" (only output)             |
     |   %U      week of the year (week starts on Sunday)           |
     |   %w      day of the week, 0--6 (Sunday = 0)                 |
     |   %W      week of the year (week starts on Monday)           |
     |   %y      year, 0-99 in range 1969-2068                      |
     |   %Y      year, 4-digit                                      |
     +--------------------------------------------------------------+
     +--------------------------------------------------------------+





   Except for the non-numerical formats, these may be preceded by a "0"
   ("zero", not "oh") to pad the field length with leading zeroes, and
   a positive digit, to define the minimum field width (which will be
   overridden if the specified width is not large enough to contain the
   number).  The %S format also accepts a precision specifier so that
   fractional seconds can be written.  There is a 24-character limit to
   the length of the printed text; longer strings will be truncated.

   Examples:

   Suppose the text is "76/12/25 23:11:11".  Then
         set format x                 # defaults to "12/25/76" \n
   "23:11"
         set format x "%A, %d %b %Y"  # "Saturday, 25 Dec 1976"
         set format x "%r %D"         # "11:11:11 pm 12/25/76"

   Suppose the text is "98/07/06 05:04:03.123456".  Then
         set format x "%1y/%2m/%3d %01H:%02M:%06.3S"  # "98/ 7/  6










   GNUPLOT 4.1                                                      162


   5:04:03.123"



             8844..2244..  FFuunnccttiioonn ssttyyllee


             This form of the command is deprecated. Please see sseett
             ssttyyllee ffuunnccttiioonn.



             8844..2255..  FFuunnccttiioonnss


             The sshhooww ffuunnccttiioonnss command lists all user-defined func-
             tions and their definitions.

             Syntax:
                   show functions

             For information about the definition and usage of func-
             tions in ggnnuupplloott, please see eexxpprreessssiioonnss.  See also
             splines as user defined functions (spline.dem) and use of
             functions and complex variables for airfoils (air-
             foil.dem).



             8844..2266..  GGrriidd


             The sseett ggrriidd command allows grid lines to be drawn on the
             plot.

             Syntax:
                   set grid {{no}{m}xtics} {{no}{m}ytics}
             {{no}{m}ztics}
                            {{no}{m}x2tics} {{no}{m}y2tics}
                            {{no}{m}cbtics}
                            {polar {<angle>}}
                            {layerdefault | front | back}
                            { {linestyle <major_linestyle>}
                              | {linetype | lt <major_linetype>}
                                {linewidth | lw <major_linewidth>}
                              { , {linestyle | ls <minor_linestyle>}
                                  | {linetype | lt <minor_linetype>}
                                    {linewidth | lw <minor_linewidth>}
             } }
                   unset grid
                   show grid

             The grid can be enabled and disabled for the major and/or










   GNUPLOT 4.1                                                      163


             minor tic marks on any axis, and the linetype and
             linewidth can be specified for major and minor grid lines,
             also via a predefined linestyle, as far as the active ter-
             minal driver supports this.

             Additionally, a polar grid can be selected for 2D
             plots---circles are drawn to intersect the selected tics,
             and radial lines are drawn at definable intervals.  (The
             interval is given in degrees or radians, depending on the
             sseett aanngglleess setting.)  Note that a polar grid is no longer
             automatically generated in polar mode.

             The pertinent tics must be enabled before sseett ggrriidd can
             draw them; ggnnuupplloott will quietly ignore instructions to
             draw grid lines at non-existent tics, but they will appear
             if the tics are subsequently enabled.

             If no linetype is specified for the minor gridlines, the
             same linetype as the major gridlines is used.  The default
             polar angle is 30 degrees.

             If ffrroonntt is given, the grid is drawn on top of the graphed
             data. If bbaacckk is given, the grid is drawn underneath the
             graphed data. Using ffrroonntt will prevent the grid from being
             obscured by dense data. The default setup, llaayyeerrddeeffaauulltt,
             is equivalent to bbaacckk for 2D plots.  In 3D plots the
             default is to split up the grid and the graph box into two
             layers: one behind, the other in front of the plotted data
             and functions. Since hhiiddddeenn33dd mode does its own sorting,
             it ignores all grid drawing order options and passes the
             grid lines through the hidden line removal machinery
             instead. These options actually affect not only the grid,
             but also the lines output by sseett bboorrddeerr and the various
             ticmarks (see sseett xxttiiccss).

             Z grid lines are drawn on the bottom of the plot.  This
             looks better if a partial box is drawn around the
             plot---see sseett bboorrddeerr.



             8844..2277..  HHiiddddeenn33dd


             The sseett hhiiddddeenn33dd command enables hidden line removal for
             surface plotting (see sspplloott).  Some optional features of
             the underlying algorithm can also be controlled using this
             command.

             Syntax:
                   set hidden3d {defaults} |
                                { {front|back}
                                  {{offset <offset>} | {nooffset}}










   GNUPLOT 4.1                                                      164


                                  {trianglepattern <bitpattern>}
                                  {{undefined <level>} | {noundefined}}
                                  {{no}altdiagonal}
                                  {{no}bentover} }
                   unset hidden3d
                   show hidden3d

             In contrast to the usual display in gnuplot, hidden line
             removal actually treats the given function or data grids
             as real surfaces that can't be seen through, so plot ele-
             ments behind the surface will be hidden by it.  For this
             to work, the surface needs to have 'grid structure' (see
             sspplloott ddaattaaffiillee about this), and it has to be drawn wwiitthh
             lliinneess or wwiitthh lliinneessppooiinnttss.

             When hhiiddddeenn33dd is set, both the hidden portion of the sur-
             face and possibly its contours drawn on the base (see sseett
             ccoonnttoouurr) as well as the grid will be hidden.  Each surface
             has its hidden parts removed with respect to itself and to
             other surfaces, if more than one surface is plotted.  Con-
             tours drawn on the surface (sseett ccoonnttoouurr ssuurrffaaccee) don't
             work.

             Labels and arrows are always visible and are unaffected.
             The key box is never hidden by the surface. As of gnuplot
             version 4.6, hidden3d also affects 3D plotting styles
             ppooiinnttss, llaabbeellss, vveeccttoorrss, and iimmppuullsseess even if no surface
             is present in the graph.  Individual plots within the
             graph may be explicitly excluded from this processing by
             appending the extra option nnoohhiiddddeenn33dd to the wwiitthh speci-
             fier.

             Hidden3d does not affect solid surfaces drawn using the
             pm3d mode. To achieve a similar effect purely for pm3d
             surfaces, use instead sseett ppmm33dd ddeepptthhoorrddeerr.  To mix pm3d
             surfaces with normal hhiiddddeenn33dd processing, use the option
             sseett hhiiddddeenn33dd ffrroonntt to force all elements included in hid-
             den3d processing to be drawn after any remaining plot ele-
             ments. Then draw the surface twice, once wwiitthh lliinneess lltt --22
             and a second time wwiitthh ppmm33dd. The first instance will
             include the surface during calculation of occluded ele-
             ments but will not draw the surface itself.

             Functions are evaluated at isoline intersections.  The
             algorithm interpolates linearly between function points or
             data points when determining the visible line segments.
             This means that the appearance of a function may be dif-
             ferent when plotted with hhiiddddeenn33dd than when plotted with
             nnoohhiiddddeenn33dd because in the latter case functions are evalu-
             ated at each sample.  Please see sseett ssaammpplleess and sseett
             iissoossaammpplleess for discussion of the difference.

             The algorithm used to remove the hidden parts of the










   GNUPLOT 4.1                                                      165


             surfaces has some additional features controllable by this
             command.  Specifying ddeeffaauullttss will set them all to their
             default settings, as detailed below.  If ddeeffaauullttss is not
             given, only explicitly specified options will be influ-
             enced: all others will keep their previous values, so you
             can turn on/off hidden line removal via sseett {{nnoo}}hhiiddddeenn33dd,
             without modifying the set of options you chose.

             The first option, ooffffsseett, influences the linetype used for
             lines on the 'back' side.  Normally, they are drawn in a
             linetype one index number higher than the one used for the
             front, to make the two sides of the surface distinguish-
             able.  You can specify a different linetype offset to add
             instead of the default 1, by ooffffsseett <<ooffffsseett>>.  Option
             nnooooffffsseett stands for ooffffsseett 00, making the two sides of the
             surface use the same linetype.

             Next comes the option ttrriiaanngglleeppaatttteerrnn <<bbiittppaatttteerrnn>>.  <bit-
             pattern> must be a number between 0 and 7, interpreted as
             a bit pattern.  Each bit determines the visibility of one
             edge of the triangles each surface is split up into.  Bit
             0 is for the 'horizontal' edges of the grid, Bit 1 for the
             'vertical' ones, and Bit 2 for the diagonals that split
             each cell of the original grid into two triangles.  The
             default pattern is 3, making all horizontal and vertical
             lines visible, but not the diagonals.  You may want to
             choose 7 to see those diagonals as well.

             The uunnddeeffiinneedd <<lleevveell>> option lets you decide what the
             algorithm is to do with data points that are undefined
             (missing data, or undefined function values), or exceed
             the given x-, y- or z-ranges.  Such points can either be
             plotted nevertheless, or taken out of the input data set.
             All surface elements touching a point that is taken out
             will be taken out as well, thus creating a hole in the
             surface.  If <level> = 3, equivalent to option nnoouunnddee--
             ffiinneedd, no points will be thrown away at all.  This may
             produce all kinds of problems elsewhere, so you should
             avoid this.  <level> = 2 will throw away undefined points,
             but keep the out-of-range ones.  <level> = 1, the default,
             will get rid of out-of-range points as well.

             By specifying nnooaallttddiiaaggoonnaall, you can override the default
             handling of a special case can occur if uunnddeeffiinneedd is
             active (i.e. <level> is not 3).  Each cell of the grid-
             structured input surface will be divided in two triangles
             along one of its diagonals.  Normally, all these diagonals
             have the same orientation relative to the grid.  If
             exactly one of the four cell corners is excluded by the
             uunnddeeffiinneedd handler, and this is on the usual diagonal, both
             triangles will be excluded.  However if the default set-
             ting of aallttddiiaaggoonnaall is active, the other diagonal will be
             chosen for this cell instead, minimizing the size of the










   GNUPLOT 4.1                                                      166


             hole in the surface.

             The bbeennttoovveerr option controls what happens to another spe-
             cial case, this time in conjunction with the ttrriiaanngglleeppaatt--
             tteerrnn.  For rather crumply surfaces, it can happen that the
             two triangles a surface cell is divided into are seen from
             opposite sides (i.e. the original quadrangle is 'bent
             over'), as illustrated in the following ASCII art:

                                                                           C----B
                 original quadrangle:  A--B      displayed quadrangle:
             |\   |
                   ("set view 0,0")    | /|    ("set view 75,75" per-
             haps)  | \  |
                                       |/ |
             |  \ |
                                       C--D
             |   \|
                                                                           A
             D

             If the diagonal edges of the surface cells aren't gener-
             ally made visible by bit 2 of the <bitpattern> there, the
             edge CB above wouldn't be drawn at all, normally, making
             the resulting display hard to understand.  Therefore, the
             default option of bbeennttoovveerr will turn it visible in this
             case.  If you don't want that, you may choose nnoobbeennttoovveerr
             instead.  See also hidden line removal demo (hidden.dem)
             and complex hidden line demo (singulr.dem).



             8844..2288..  HHiissttoorryyssiizzee


             Note: the command sseett hhiissttoorryyssiizzee is only available when
             gnuplot has been configured to use the GNU readline
             library.

             Syntax:
                   set historysize <int>
                   unset historysize

             When leaving gnuplot, the value of historysize is used for
             truncating the history to at most that much lines. The
             default is 500.  uunnsseett hhiissttoorryyssiizzee will disable history
             truncation and thus allow an infinite number of lines to
             be written to the history file.















   GNUPLOT 4.1                                                      167


             8844..2299..  IIssoossaammpplleess


             The isoline density (grid) for plotting functions as sur-
             faces may be changed by the sseett iissoossaammpplleess command.

             Syntax:
                   set isosamples <iso_1> {,<iso_2>}
                   show isosamples

             Each function surface plot will have <iso_1> iso-u lines
             and <iso_2> iso-v lines.  If you only specify <iso_1>,
             <iso_2> will be set to the same value as <iso_1>.  By
             default, sampling is set to 10 isolines per u or v axis.
             A higher sampling rate will produce more accurate plots,
             but will take longer.  These parameters have no effect on
             data file plotting.

             An isoline is a curve parameterized by one of the surface
             parameters while the other surface parameter is fixed.
             Isolines provide a simple means to display a surface.  By
             fixing the u parameter of surface s(u,v), the iso-u lines
             of the form c(v) = s(u0,v) are produced, and by fixing the
             v parameter, the iso-v lines of the form c(u) = s(u,v0)
             are produced.

             When a function surface plot is being done without the
             removal of hidden lines, sseett ssaammpplleess  controls the number
             of points sampled along each isoline;  see sseett ssaammpplleess and
             sseett hhiiddddeenn33dd. The contour algorithm assumes that a func-
             tion sample occurs at each isoline intersection, so change
             in ssaammpplleess as well as iissoossaammpplleess may be desired when
             changing the resolution of a function surface/contour.



             8844..3300..  KKeeyy


             The sseett kkeeyy command enables a key (or legend) describing
             plots on a plot.

             The contents of the key, i.e., the names given to each
             plotted data set and function and samples of the lines
             and/or symbols used to represent them, are determined by
             the ttiittllee and wwiitthh options of the {ss}pplloott command.  Please
             see pplloott ttiittllee and pplloott wwiitthh for more information.

             Syntax:
                   set key {on|off} {default}
                           {{inside | outside} | {lmargin | rmargin |
             tmargin | bmargin}
                             | {at <position>}}










   GNUPLOT 4.1                                                      168


                           {left | right | center} {top | bottom | cen-
             ter}
                           {vertical | horizontal} {Left | Right}
                           {{no}opaque}
                           {{no}reverse} {{no}invert}
                           {samplen <sample_length>} {spacing <verti-
             cal_spacing>}
                           {width <width_increment>}
                           {height <height_increment>}
                           {{no}autotitle {columnheader}}
                           {title "<text>"} {{no}enhanced}
                           {font "<face>,<size>"} {textcolor <color-
             spec>}
                           {{no}box { {linestyle | ls <line_style>}
                                      | {linetype | lt <line_type>}
                                        {linewidth | lw <line_width>}}}
                           {maxcols {<max no. of columns> | auto}}
                           {maxrows {<max no. of rows> | auto}}
                   unset key
                   show key

             The key contains a title and a sample (line, point, box)
             for each plot in the graph. The key may be turned off by
             requesting sseett kkeeyy ooffff or uunnsseett kkeeyy.  Individual key
             entries may be turned off by using the nnoottiittllee keyword in
             the corresponding plot command.

             Elements within the key are stacked according to vveerrttiiccaall
             or hhoorriizzoonnttaall.  In the case of vveerrttiiccaall, the key occupies
             as few columns as possible.  That is, elements are aligned
             in a column until running out of vertical space at which
             point a new column is started.  The vertical space may be
             limited using 'maxrows'.  In the case of hhoorriizzoonnttaall, the
             key occupies as few rows as possible.  The horizontal
             space may be limited using 'maxcols'.

             By default the key is placed in the upper right inside
             corner of the graph.  The keywords lleefftt, rriigghhtt, ttoopp, bboott--
             ttoomm, cceenntteerr, iinnssiiddee, oouuttssiiddee, llmmaarrggiinn, rrmmaarrggiinn, ttmmaarrggiinn,
             bbmmaarrggiinn (, aabboovvee, oovveerr, bbeellooww and uunnddeerr) may be used to
             automatically place the key in other positions of the
             graph.  Also an aatt <<ppoossiittiioonn>> may be given to indicate
             precisely where the plot should be placed.  In this case,
             the keywords lleefftt, rriigghhtt, ttoopp, bboottttoomm and cceenntteerr serve an
             analogous purpose for alignment.  For more information,
             see kkeeyy ppllaacceemmeenntt.

             Justification of the plot titles within the key is con-
             trolled by LLeefftt or RRiigghhtt (default).  The text and sample
             can be reversed (rreevveerrssee) and a box can be drawn around
             the key (bbooxx {{......}}) in a specified lliinneettyyppee and lliinneewwiiddtthh,
             or a user-defined lliinneessttyyllee.











   GNUPLOT 4.1                                                      169


             By default the key is built up one plot at a time. That
             is, the key symbol and title are drawn at the same time as
             the corresponding plot.  That means newer plots may some-
             times place elements on top of the key.  sseett kkeeyy ooppaaqquuee
             causes the key to be generated after all the plots.  In
             this case the key area is filled with background color and
             then the key symbols and titles are written.  Therefore
             the key itself may obscure portions of some plot elements.
             The default can be restored by sseett kkeeyy nnooooppaaqquuee.

             By default the first plot label is at the top of the key
             and successive labels are entered below it. The iinnvveerrtt
             option causes the first label to be placed at the bottom
             of the key, with successive labels entered above it. This
             option is useful to force the vertical ordering of labels
             in the key to match the order of box types in a stacked
             histogram.

             The <height_increment> is a number of character heights to
             be added to or subtracted from the height of the key box.
             This is useful mainly when you are putting a box around
             the key and want larger borders around the key entries.

             All plotted curves of ppllootts and ssppllootts are titled accord-
             ing to the default option aauuttoottiittlleess. The automatic gener-
             ation of titles can be suppressed by nnooaauuttoottiittlleess; then
             only those titles explicitly defined by ((ss))pplloott ...... ttiittllee
             ...... will be drawn.

             The command sseett kkeeyy aauuttoottiittllee ccoolluummnnhheeaaddeerr causes the
             first entry in each column of input data to be interpreted
             as a text string and used as a title for the corresponding
             plot. If the quantity being plotted is a function of data
             from several columns, gnuplot may be confused as to which
             column to draw the title from. In this case it is neces-
             sary to specify the column explicitly in the plot command,
             e.g.

                   plot "datafile" using (($2+$3)/$4) title column-
             head(3) with lines

             An overall title can be put on the key (ttiittllee
             ""<<tteexxtt>>"")---see also ssyynnttaaxx for the distinction between
             text in single- or double-quotes.  The key title uses the
             same justification as do the plot titles.

             The defaults for sseett kkeeyy are oonn, rriigghhtt, ttoopp, vveerrttiiccaall,
             RRiigghhtt, nnoorreevveerrssee, nnooiinnvveerrtt, ssaammpplleenn 44, ssppaacciinngg 11..2255, ttiittllee
             """", and nnoobbooxx.  The default <linetype> is the same as that
             used for the plot borders.  Entering sseett kkeeyy ddeeffaauulltt
             returns the key to its default configuration.

             The key is drawn as a sequence of lines, with one plot










   GNUPLOT 4.1                                                      170


             described on each line.  On the right-hand side (or the
             left-hand side, if rreevveerrssee is selected) of each line is a
             representation that attempts to mimic the way the curve is
             plotted.  On the other side of each line is the text
             description (the line title), obtained from the pplloott com-
             mand.  The lines are vertically arranged so that an imagi-
             nary straight line divides the left- and right-hand sides
             of the key.  It is the coordinates of the top of this line
             that are specified with the sseett kkeeyy command.  In a pplloott,
             only the x and y coordinates are used to specify the line
             position.  For a sspplloott, x, y and z are all used as a 3D
             location mapped using the same mapping as the graph itself
             to form the required 2D screen position of the imaginary
             line.

             When using the TeX or other terminals where formatting
             information is embedded in the string, ggnnuupplloott can only
             estimate the correctly exact width of the string for key
             positioning.  If the key is to be positioned at the left,
             it may be convenient to use the combination  sseett kkeeyy lleefftt
             LLeefftt rreevveerrssee.

             If sspplloott is being used to draw contours, the contour
             labels will be listed in the key.  If the alignment of
             these labels is poor or a different number of decimal
             places is desired, the label format can be specified.  See
             sseett ccllaabbeell for details.

             Examples:

             This places the key at the default location:
                   set key default

             This disables the key:
                   unset key

             This places a key at coordinates 2,3.5,2 in the default
             (first) coordinate system:
                   set key at 2,3.5,2

             This places the key below the graph:
                   set key below

             This places the key in the bottom left corner, left-justi-
             fies the text, gives it a title, and draws a box around it
             in linetype 3:
                   set key left bottom Left title 'Legend' box 3
















   GNUPLOT 4.1                                                      171


                  8844..3300..11..  KKeeyy ppllaacceemmeenntt


                  To understand positioning, the best concept is to
                  think of a region, i.e., inside/outside, or one of
                  the margins.  Along with the region, keywords
                  lleefftt//cceenntteerr//rriigghhtt (l/c/r) and ttoopp//cceenntteerr//bboottttoomm
                  (t/c/b) control where within the particular region
                  the key should be placed.

                  When in iinnssiiddee mode, the keywords lleefftt (l), rriigghhtt
                  (r), ttoopp (t), bboottttoomm (b), and cceenntteerr (c) push the key
                  out toward the plot boundary as illustrated:

                       t/l   t/c   t/r

                       c/l    c    c/r

                       b/l   b/c   b/r


                  When in oouuttssiiddee mode, automatic placement is similar
                  to the above illustration, but with respect to the
                  view, rather than the graph boundary.  That is, a
                  border is moved inward to make room for the key out-
                  side of the plotting area, although this may inter-
                  fere with other labels and may cause an error on some
                  devices.  The particular plot border that is moved
                  depends upon the position described above and the
                  stacking direction.  For options centered in one of
                  the dimensions, there is no ambiguity about which
                  border to move.  For the corners, when the stack
                  direction is vveerrttiiccaall, the left or right border is
                  moved inward appropriately.  When the stack direction
                  is hhoorriizzoonnttaall, the top or bottom border is moved
                  inward appropriately.

                  The margin syntax allows automatic placement of key
                  regardless of stack direction.  When one of the mar-
                  gins llmmaarrggiinn (lm), rrmmaarrggiinn (rm), ttmmaarrggiinn (tm), and
                  bbmmaarrggiinn (bm) is combined with a single, non-conflict-
                  ing direction keyword, the following illustrated
                  positions may contain the key:

                            l/tm  c/tm  r/tm

                       t/lm                  t/rm

                       c/lm                  c/rm

                       b/lm                  b/rm

                            l/bm  c/bm  r/bm










   GNUPLOT 4.1                                                      172


                  Keywords aabboovvee and oovveerr are synonymous with ttmmaarrggiinn.
                  For version compatibility, aabboovvee or oovveerr without an
                  additional l/c/r or stack direction keyword uses cceenn--
                  tteerr and hhoorriizzoonnttaall.  Keywords bbeellooww and uunnddeerr are
                  synonymous with bbmmaarrggiinn.  For compatibility, bbeellooww or
                  uunnddeerr without an additional l/c/r or stack  direction
                  keyword uses cceenntteerr and hhoorriizzoonnttaall.  A further com-
                  patibility issue is that oouuttssiiddee appearing without an
                  additional t/b/c or stack direction keyword uses ttoopp,
                  rriigghhtt and vveerrttiiccaall (i.e., the same as t/rm above).

                  The <position> can be a simple x,y,z as in previous
                  versions, but these can be preceded by one of five
                  keywords (ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, cchhaarraacctteerr)
                  which selects the coordinate system in which the
                  position of the first sample line is specified.  See
                  ccoooorrddiinnaatteess for more details.  The effect of lleefftt,
                  rriigghhtt, ttoopp, bboottttoomm, and cceenntteerr when <position> is
                  given is to align the key as though it were text
                  positioned using the label command, i.e., lleefftt means
                  left align with key to the right of <position>, etc.



                  8844..3300..22..  KKeeyy ssaammpplleess


                  By default, each plot on the graph generates a corre-
                  sponding entry in the key.  This entry contains a
                  plot title and a sample line/point/box of the same
                  color and fill properties as used in the plot itself.
                  The font and textcolor properties control the appear-
                  ance of the individual plot titles that appear in the
                  key. Setting the textcolor to "variable" causes the
                  text for each key entry to be the same color as the
                  line or fill color for that plot.  This was the
                  default in some earlier versions of gnuplot.

                  The length of the sample line can be controlled by
                  ssaammpplleenn.  The sample length is computed as the sum of
                  the tic length and <sample_length> times the charac-
                  ter width.  ssaammpplleenn also affects the positions of
                  point samples in the key since these are drawn at the
                  midpoint of the sample line, even if the sample line
                  itself is not drawn.

                  The vertical spacing between lines is controlled by
                  ssppaacciinngg.  The spacing is set equal to the product of
                  the pointsize, the vertical tic size, and <verti-
                  cal_spacing>.  The program will guarantee that the
                  vertical spacing is no smaller than the character
                  height.











   GNUPLOT 4.1                                                      173


                  The <width_increment> is a number of character widths
                  to be added to or subtracted from the length of the
                  string.  This is useful only when you are putting a
                  box around the key and you are using control charac-
                  ters in the text.  ggnnuupplloott simply counts the number
                  of characters in the string when computing the box
                  width; this allows you to correct it.



             8844..3311..  LLaabbeell


             Arbitrary labels can be placed on the plot using the sseett
             llaabbeell command.

             Syntax:
                   set label {<tag>} {"<label text>"} {at <position>}
                             {left | center | right}
                             {norotate | rotate {by <degrees>}}
                             {font "<name>{,<size>}"}
                             {noenhanced}
                             {front | back}
                             {textcolor <colorspec>}
                             {point <pointstyle> | nopoint}
                             {offset <offset>}
                   unset label {<tag>}
                   show label

             The <position> is specified by either x,y or x,y,z, and
             may be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarr--
             aacctteerr to select the coordinate system.  See ccoooorrddiinnaatteess
             for details.

             The tag is an integer that is used to identify the label.
             If no <tag> is given, the lowest unused tag value is
             assigned automatically.  The tag can be used to delete or
             modify a specific label.  To change any attribute of an
             existing label, use the sseett llaabbeell command with the appro-
             priate tag, and specify the parts of the label to be
             changed.

             The <label text> can be a string constant, a string vari-
             able, or a string- valued expression. See ssttrriinnggss,
             sspprriinnttff, and ggpprriinnttff.

             By default, the text is placed flush left against the
             point x,y,z.  To adjust the way the label is positioned
             with respect to the point x,y,z, add the justification
             parameter, which may be lleefftt, rriigghhtt or cceenntteerr, indicating
             that the point is to be at the left, right or center of
             the text.  Labels outside the plotted boundaries are per-
             mitted but may interfere with axis labels or other text.










   GNUPLOT 4.1                                                      174


             If rroottaattee is given, the label is written vertically (if
             the terminal can do so, of course).  If rroottaattee bbyy
             <<ddeeggrreeeess>> is given, conforming terminals will try to write
             the text at the specified angle; non-conforming terminals
             will treat this as vertical text.

             Font and its size can be chosen explicitly by ffoonntt
             ""<<nnaammee>>{{,,<<ssiizzee>>}}"" if the terminal supports font settings.
             Otherwise the default font of the terminal will be used.

             Normally the enhanced text mode string interpretation, if
             enabled for the current terminal, is applied to all text
             strings including label text.  The nnooeennhhaanncceedd property can
             be used to exempt a specific label from the enhanced text
             mode processing.  The can be useful if the label contains
             underscores, for example. See eennhhaanncceedd tteexxtt.

             If ffrroonntt is given, the label is written on top of the
             graphed data. If bbaacckk is given (the default), the label is
             written underneath the graphed data.  Using ffrroonntt will
             prevent a label from being obscured by dense data.

             tteexxttccoolloorr <<ccoolloorrssppeecc>> changes the color of the label text.
             <colorspec> can be a linetype, an rgb color, or a palette
             mapping. See help for ccoolloorrssppeecc and ppaalleettttee.  tteexxttccoolloorr
             may be abbreviated ttcc.
                `tc default` resets the text color to its default
             state.
                `tc lt <n>` sets the text color to that of line type
             <n>.
                `tc ls <n>` sets the text color to that of line style
             <n>.
                `tc palette z` selects a palette color corresponding to
             the label z position.
                `tc palette cb <val>` selects a color corresponding to
             <val> on the colorbar.
                `tc palette fraction <val>`, with 0<=val<=1, selects a
             color corresponding to
                    the mapping [0:1] to grays/colors of the `palette`.
                `tc rgb "#RRGGBB"` selects an arbitrary 24-bit RGB
             color.

             If a <pointstyle> is given, using keywords lltt, pptt and ppss,
             see ssttyyllee, a point with the given style and color of the
             given line type is plotted at the label position and the
             text of the label is displaced slightly.  This option is
             used by default for placing labels in mmoouussee enhanced ter-
             minals.  Use nnooppooiinntt to turn off the drawing of a point
             near the label (this is the default).

             The displacement defaults to 1,1 in ppooiinnttssiizzee units if a
             <pointstyle> is given, 0,0 if no <pointstyle> is given.
             The displacement can be controlled by the optional ooffffsseett










   GNUPLOT 4.1                                                      175


             <<ooffffsseett>> where <offset> is specified by either x,y or
             x,y,z, and may be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh,
             ssccrreeeenn, or cchhaarraacctteerr to select the coordinate system.  See
             ccoooorrddiinnaatteess for details.

             If one (or more) axis is timeseries, the appropriate coor-
             dinate should be given as a quoted time string according
             to the ttiimmeeffmmtt format string.  See sseett xxddaattaa and sseett
             ttiimmeeffmmtt.

             The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a
             string to specify a newline.

             Label coordinates and text can also be read from a data
             file (see llaabbeellss).

             Examples:

             To set a label at (1,2) to "y=x", use:
                   set label "y=x" at 1,2

             To set a Sigma of size 24, from the Symbol font set, at
             the center of the graph, use:
                   set label "S" at graph 0.5,0.5 center font "Sym-
             bol,24"

             To set a label "y=x^2" with the right of the text at
             (2,3,4), and tag the label as number 3, use:
                   set label 3 "y=x^2" at 2,3,4 right

             To change the preceding label to center justification,
             use:
                   set label 3 center

             To delete label number 2, use:
                   unset label 2

             To delete all labels, use:
                   unset label

             To show all labels (in tag order), use:
                   show label

             To set a label on a graph with a timeseries on the x axis,
             use, for example:
                   set timefmt "%d/%m/%y,%H:%M"
                   set label "Harvest" at "25/8/93",1

             To display a freshly fitted parameter on the plot with the
             data and the fitted function, do this after the ffiitt, but
             before the pplloott:
                   set label sprintf("a = %3.5g",par_a) at 30,15
                   bfit = gprintf("b = %s*10^%S",par_b)










   GNUPLOT 4.1                                                      176


                   set label bfit at 30,20

             To display a function definition along with its fitted
             parameters, use:
                   f(x)=a+b*x
                   fit f(x) 'datafile' via a,b
                   set label GPFUN_f at graph .05,.95
                   set label sprintf("a = %g", a) at graph .05,.90
                   set label sprintf("b = %g", b) at graph .05,.85

             To set a label displaced a little bit from a small point:
                   set label 'origin' at 0,0 point lt 1 pt 2 ps 3 off-
             set 1,-1

             To set a label whose color matches the z value (in this
             case 5.5) of some point on a 3D splot colored using pm3d:
                   set label 'text' at 0,0,5.5 tc palette z



             8844..3322..  LLiinneettyyppee


             The sseett lliinneettyyppee command allows you to redefine the basic
             linetypes used for plots.  The command options are identi-
             cal to those for "set style line".  Unlike line styles,
             redefinitions by sseett lliinneettyyppee are persistent;  they are
             not affected by rreesseett.

             For example, linetypes one and two default to red and
             green. If you redefine them like this:

                   set linetype 1 lw 2 lc rgb "blue" pointtype 6
                   set linetype 2 lw 2 lc rgb "forest-green" pointtype
             8

             everywhere that uses lt 1 will now get a thick blue line
             rather than a thin red line (the previous default meaning
             of lt 1).  This includes uses such as the definition of a
             temporary linestyle derived from the base linetype 1.

             NNoottee: This command is new to gnuplot version 4.6.  It
             supersedes a rather cryptic command in version 4.2 "set
             style increment user".  The older command is now depre-
             cated.

             This mechanism can be used to define a set of personal
             preferences for the sequence of lines used in gnuplot.
             The recommended way to do this is to add to the run-time
             initialization file ~/.gnuplot a sequence of commands like

                   if ((GPVAL_VERSION < 4.5) \
                   ||










   GNUPLOT 4.1                                                      177


             (!strstrt(GPVAL_COMPILE_OPTIONS,"+USER_LINETYPES"))) \
                       exit
                   set linetype 1 lc rgb "dark-violet" lw 2 pt 0
                   set linetype 2 lc rgb "sea-green"   lw 2 pt 7
                   set linetype 3 lc rgb "cyan"        lw 2 pt 6 pi -1
                   set linetype 4 lc rgb "dark-red"    lw 2 pt 5 pi -1
                   set linetype 5 lc rgb "blue"        lw 2 pt 8
                   set linetype 6 lc rgb "dark-orange" lw 2 pt 3
                   set linetype 7 lc rgb "black"       lw 2 pt 11
                   set linetype 8 lc rgb "goldenrod"   lw 2
                   set linetype cycle 8

             Every time you run gnuplot the line types will be initial-
             ized to these values.  You may initialize as many line-
             types as you like. If you do not redefine, say, linetype 3
             then it will continue to have the default properties (in
             this case blue, pt 3, lw 1, etc).  The first few lines of
             the example script insure that the commands will be
             skipped by older versions of gnuplot.

             Similar script files can be used to define theme-based
             color choices, or sets of colors optimized for a particu-
             lar plot type or output device.

             The command sseett lliinneettyyppee ccyyccllee 88 tells gnuplot to re-use
             these definitions for the color and linewidth of higher-
             numbered linetypes.  That is, linetypes 9-16, 17-24, and
             so on will use this same sequence of colors and widths.
             The point properties (pointtype, pointsize, pointinterval)
             are not affected by this command.  uunnsseett lliinneettyyppee ccyyccllee
             disables this feature.  If the line properties of a higher
             numbered linetype are explicitly defined, this takes
             precedence over the recycled low-number linetype proper-
             ties.




             8844..3333..  LLmmaarrggiinn


             The command sseett llmmaarrggiinn sets the size of the left margin.
             Please see sseett mmaarrggiinn for details.



             8844..3344..  LLooaaddppaatthh


             The llooaaddppaatthh setting defines additional locations for data
             and command files searched by the ccaallll, llooaadd, pplloott and
             sspplloott commands.  If a file cannot be found in the current
             directory, the directories in llooaaddppaatthh are tried.










   GNUPLOT 4.1                                                      178


             Syntax:
                   set loadpath {"pathlist1" {"pathlist2"...}}
                   show loadpath

             Path names may be entered as single directory names, or as
             a list of path names separated by a platform-specific path
             separator, eg. colon (':') on Unix, semicolon (';') on
             DOS/Windows/OS/2 platforms.  The sshhooww llooaaddppaatthh, ssaavvee and
             ssaavvee sseett commands replace the platform-specific separator
             with a space character (' ').

             If the environment variable GNUPLOT_LIB is set, its con-
             tents are appended to llooaaddppaatthh.  However, sshhooww llooaaddppaatthh
             prints the contents of sseett llooaaddppaatthh and GNUPLOT_LIB sepa-
             rately.  Also, the ssaavvee and ssaavvee sseett commands ignore the
             contents of GNUPLOT_LIB.



             8844..3355..  LLooccaallee


             The llooccaallee setting determines the language with which
             {{xx,,yy,,zz}}{{dd,,mm}}ttiiccss will write the days and months.

             Syntax:
                   set locale {"<locale>"}

             <locale> may be any language designation acceptable to
             your installation.  See your system documentation for the
             available options.  The command sseett llooccaallee """" will try to
             determine the locale from the LC_TIME, LC_ALL, or LANG
             environment variables.

             To change the decimal point locale, see sseett ddeecciimmaallssiiggnn.
             To change the character encoding to the current locale,
             see sseett eennccooddiinngg.



             8844..3366..  LLooggssccaallee


             Syntax:
                   set logscale <axes> {<base>}
                   unset logscale <axes>
                   show logscale

             where <axes> may be any combinations of xx, xx22, yy, yy22, zz,
             ccbb, and rr in any order.  <base> is the base of the log
             scaling (default is base 10).  If no axes are specified,
             the command affects all axes except rr.  The command uunnsseett
             llooggssccaallee turns off log scaling for all axes.  Note that










   GNUPLOT 4.1                                                      179


             the ticmarks generated for logscaled axes are not uni-
             formly spaced.  See sseett xxttiiccss.

             Examples:

             To enable log scaling in both x and z axes:
                   set logscale xz

             To enable scaling log base 2 of the y axis:
                   set logscale y 2

             To enable z and color log axes for a pm3d plot:
                   set logscale zcb

             To disable z axis log scaling:
                   unset logscale z



             8844..3377..  MMaaccrrooss


             If command line macro substitution is enabled, then tokens
             in the command line of the form @<stringvariablename> will
             be replaced by the text string contained in <stringvari-
             ablename>. See ssuubbssttiittuuttiioonn.

             Syntax:
                  set macros




             8844..3388..  MMaappppiinngg


             If data are provided to sspplloott in spherical or cylindrical
             coordinates, the sseett mmaappppiinngg command should be used to
             instruct ggnnuupplloott how to interpret them.

             Syntax:
                   set mapping {cartesian | spherical | cylindrical}

             A cartesian coordinate system is used by default.

             For a spherical coordinate system, the data occupy two or
             three columns (or uussiinngg entries).  The first two are
             interpreted as the azimuthal and polar angles theta and
             phi (or "longitude" and "latitude"), in the units speci-
             fied by sseett aanngglleess.  The radius r is taken from the third
             column if there is one, or is set to unity if there is no
             third column.  The mapping is:











   GNUPLOT 4.1                                                      180


                   x = r * cos(theta) * cos(phi)
                   y = r * sin(theta) * cos(phi)
                   z = r * sin(phi)

             Note that this is a "geographic" spherical system, rather
             than a "polar" one (that is, phi is measured from the
             equator, rather than the pole).

             For a cylindrical coordinate system, the data again occupy
             two or three columns.  The first two are interpreted as
             theta (in the units specified by sseett aanngglleess) and z.  The
             radius is either taken from the third column or set to
             unity, as in the spherical case.  The mapping is:

                   x = r * cos(theta)
                   y = r * sin(theta)
                   z = z

             The effects of mmaappppiinngg can be duplicated with the uussiinngg
             filter on the sspplloott command, but mmaappppiinngg may be more con-
             venient if many data files are to be processed.  However
             even if mmaappppiinngg is used, uussiinngg may still be necessary if
             the data in the file are not in the required order.

             mmaappppiinngg has no effect on pplloott.  world.dem: mapping demos.



             8844..3399..  MMaarrggiinn


             The mmaarrggiinn is the distance between the plot border and the
             outer edge of the canvas. The size of the margin is chosen
             automatically, but can be overridden by the sseett mmaarrggiinn
             commands.  sshhooww mmaarrggiinn shows the current settings.  To
             alter the distance between the inside of the plot border
             and the data in the plot itself, see sseett ooffffsseettss.

             Syntax:
                   set bmargin {{at screen} <margin>}
                   set lmargin {{at screen} <margin>}
                   set rmargin {{at screen} <margin>}
                   set tmargin {{at screen} <margin>}
                   show margin

             The default units of <margin> are character heights or
             widths, as appropriate.  A positive value defines the
             absolute size of the margin.  A negative value (or none)
             causes ggnnuupplloott to revert to the computed value.  For 3D
             plots, only the left margin can be set using character
             units.

             The keywords aatt ssccrreeeenn indicates that the margin is










   GNUPLOT 4.1                                                      181


             specified as a fraction of the full drawing area. This can
             be used to precisely line up the corners of individual 2D
             and 3D graphs in a multiplot. This placement ignores the
             current values of sseett oorriiggiinn and sseett ssiizzee, and is intended
             as an alternative method for positioning graphs within a
             multiplot.

             Normally the margins of a plot are automatically calcu-
             lated based on tics, tic labels, axis labels, the plot
             title, the timestamp and the size of the key if it is out-
             side the borders.  If, however, tics are attached to the
             axes (sseett xxttiiccss aaxxiiss, for example), neither the tics them-
             selves nor their labels will be included in either the
             margin calculation or the calculation of the positions of
             other text to be written in the margin.  This can lead to
             tic labels overwriting other text if the axis is very
             close to the border.



             8844..4400..  MMoouussee


             The command sseett mmoouussee enables mouse actions for the cur-
             rent interactive terminal.  It is usually enabled by
             default in interactive mode, but disabled by default if
             commands are being read from a file.

             There are two mouse modes. The 2D mode works for pplloott com-
             mands and for sspplloott maps (i.e. sseett vviieeww with z-rotation 0,
             90, 180, 270 or 360 degrees, including sseett vviieeww mmaapp).  In
             this mode the mouse position is tracked and you can pan or
             zoom using the mouse buttons or arrow keys.  Some termi-
             nals support toggling individual plots on/off by clicking
             on the corresponding key title or on a separate widget.

             For 3D graphs sspplloott, the view and scaling of the graph can
             be changed with mouse buttons 1 and 2, respectively. A
             vertical motion of Button 2 with the shift key held down
             changes the xxyyppllaannee.  If additionally to these buttons the
             modifier <ctrl> is held down, the coordinate axes are dis-
             played but the data are suppressed.  This is useful for
             large data sets.

             Mousing is not available inside multiplot mode. When mul-
             tiplot is completed using uunnsseett mmuullttiipplloott, then the mouse
             will be turned on again but acts only on the most recent
             plot within the multiplot (like replot does).

             Syntax:
                   set mouse {doubleclick <ms>} {nodoubleclick} \
                             {{no}zoomcoordinates} \
                             {noruler | ruler {at x,y}} \










   GNUPLOT 4.1                                                      182


                             {polardistance{deg|tan} | nopolardistance}
             \
                             {format <string>} \
                             {clipboardformat <int>/<string>} \
                             {mouseformat <int>/<string>} \
                             {{no}labels {"labeloptions"}} \
                             {{no}zoomjump} {{no}verbose}
                   unset mouse

             The options nnoorruulleerr and rruulleerr switch the ruler off and on,
             the latter optionally setting the origin at the given
             coordinates. While the ruler is on, the distance in user
             units from the ruler origin to the mouse is displayed con-
             tinuously. By default, toggling the ruler has the key
             binding 'r'.

             The option ppoollaarrddiissttaannccee determines if the distance
             between the mouse cursor and the ruler is also shown in
             polar coordinates (distance and angle in degrees or tan-
             gent (slope)). This corresponds to the default key binding
             '5'.

             Choose the option llaabbeellss to define persistent gnuplot
             labels using Button 2.  The default is nnoollaabbeellss, which
             makes Button 2 draw only a temporary label at the mouse
             position. Labels are drawn with the current setting of
             mmoouusseeffoorrmmaatt.  The llaabbeellooppttiioonnss string is passed to the sseett
             llaabbeell command.  The default is "point pointstyle 1" which
             will plot a small plus at the label position.  Temporary
             labels will disappear at the next rreepplloott or mouse zoom
             operation.  Persistent labels can be removed by holding
             the Ctrl-Key down while clicking Button 2 on the label's
             point. The threshold for how close you must be to the
             label is also determined by the ppooiinnttssiizzee.

             If the option vveerrbboossee is turned on the communication com-
             mands are shown during execution. This option can also be
             toggled by hitting 66 in the driver's window. vveerrbboossee is
             off by default.

             Press 'h' in the driver's window for a short summary of
             the mouse and key bindings.  This will also display user
             defined bindings or hhoottkkeeyyss which can be defined using the
             bbiinndd command, see help for bbiinndd.  Note, that user defined
             hhoottkkeeyyss may override the default bindings.  See also help
             for bbiinndd and llaabbeell.

















   GNUPLOT 4.1                                                      183


                  8844..4400..11..  DDoouubblleecclliicckk


                  The doubleclick resolution is given in milliseconds
                  and used for Button 1, which copies the current mouse
                  position to the cclliippbbooaarrdd.  The default value is 300
                  ms.  Setting the value to 0 ms triggers the copy on a
                  single click.



                  8844..4400..22..  MMoouusseeffoorrmmaatt


                  The sseett mmoouussee ffoorrmmaatt command specifies a format
                  string for sprintf() which determines how the mouse
                  cursor [x,y] coordinates are printed to the plot win-
                  dow and to the clipboard.  The default is "% #g".

                  sseett mmoouussee cclliippbbooaarrddffoorrmmaatt and sseett mmoouussee mmoouusseeffoorrmmaatt
                  are used for formatting the text on Button1 and But-
                  ton2 actions -- copying the coordinates to the clip-
                  board and temporarily annotating the mouse position.
                  An integer argument selects one of the format options
                  in the table below. A string argument is used as a
                  format for sprintf() in option 6 and should contain
                  two float specifiers.  Example:
                       `set mouse mouseformat "mouse x,y = %5.2g,
                  %10.3f"`.
                  Use sseett mmoouussee mmoouusseeffoorrmmaatt """" to turn this string off
                  again.

                  The following formats are available:

                   0   default (same as 1)
                   1   axis coordinates                    1.23, 2.45
                   2   graph coordinates (from 0 to 1)    /0.00, 1.00/
                   3   x = timefmt     y = axis           [(as set by
                  `set timefmt`), 2.45]
                   4   x = date        y = axis           [31. 12.
                  1999, 2.45]
                   5   x = time        y = axis           [23:59, 2.45]
                   6   x = date time   y = axis           [31. 12. 1999
                  23:59, 2.45]
                   7   format from `set mouse mouseformat`, e.g. "mouse
                  x,y = 1.23,     2.450"



                  8844..4400..33..  SSccrroolllliinngg













   GNUPLOT 4.1                                                      184


                  X and Y axis scaling in both 2D and 3D graphs can be
                  adjusted using the mouse wheel.  <wheel-up> scrolls
                  up (increases both YMIN and YMAX by ten percent of
                  the Y range, and increases both Y2MIN and Y2MAX like-
                  wise), and <wheel down> scrolls down.  <shift-wheel-
                  up> scrolls left (decreases both XMIN and XMAX, and
                  both X2MIN and X2MAX), and <shift-wheel-down> scrolls
                  right.  <control-wheel-up> zooms in toward the center
                  of the plot, and <control-wheel-down> zooms out.
                  <shift-control-wheel-up> zooms in along the X and X2
                  axes only, and <shift-control-wheel-down> zooms out
                  along the X and X2 axes only.



                  8844..4400..44..  XX1111 mmoouussee


                  If multiple X11 plot windows have been opened using
                  the sseett tteerrmm xx1111 <<nn>> terminal option, then only the
                  current plot window supports the entire range of
                  mouse commands and hotkeys.  The other windows will,
                  however, continue to display mouse coordinates at the
                  lower left.



                  8844..4400..55..  ZZoooomm


                  Zooming is usually accomplished by holding down the
                  left mouse button and dragging the mouse to delineate
                  a zoom region.  Some platforms may require using a
                  different mouse button.  The original plot can be
                  restored by typing the 'u' hotkey in the plot window.
                  The hotkeys 'p' and 'n' step back and forth through a
                  history of zoom operations.

                  The option zzoooommccoooorrddiinnaatteess determines if the coordi-
                  nates of the zoom box are drawn at the edges while
                  zooming. This is on by default.

                  If the option zzoooommjjuummpp is on, the mouse pointer will
                  be automatically offset a small distance after start-
                  ing a zoom region with button 3. This can be useful
                  to avoid a tiny (or even empty) zoom region. zzoooommjjuummpp
                  is off by default.
















   GNUPLOT 4.1                                                      185


             8844..4411..  MMuullttiipplloott


             The command sseett mmuullttiipplloott places ggnnuupplloott in the multiplot
             mode, in which several plots are placed on the same page,
             window, or screen.

             Syntax:
                   set multiplot
                       { title <page title> {font <fontspec>}
             {enhanced|noenhanced} }
                       { layout <rows>,<cols>
                         {rowsfirst|columnsfirst} {downwards|upwards}
                         {scale <xscale>{,<yscale>}} {offset
             <xoff>{,<yoff>}}
                       }
                   unset multiplot

             For some terminals, no plot is displayed until the command
             uunnsseett mmuullttiipplloott is given, which causes the entire page to
             be drawn and then returns gnuplot to its normal single-
             plot mode.  For other terminals, each separate pplloott com-
             mand produces an updated display, either by redrawing all
             previous ones and the newly added plot, or by just adding
             the new plot to the existing display.

             The area to be used by the next plot is not erased before
             doing the new plot.  The cclleeaarr command can be used to do
             this if wanted, as is typically the case for "inset"
             plots.

             Any labels or arrows that have been defined will be drawn
             for each plot according to the current size and origin
             (unless their coordinates are defined in the ssccrreeeenn sys-
             tem).  Just about everything else that can be sseett is
             applied to each plot, too.  If you want something to
             appear only once on the page, for instance a single time
             stamp, you'll need to put a sseett ttiimmee/uunnsseett ttiimmee pair
             around one of the pplloott, sspplloott or rreepplloott commands within
             the sseett mmuullttiipplloott/uunnsseett mmuullttiipplloott block.

             The multiplot title is separate from the individual plot
             titles, if any.  Space is reserved for it at the top of
             the page, spanning the full width of the canvas.

             The commands sseett oorriiggiinn and sseett ssiizzee must be used to cor-
             rectly position each plot if no layout is specified or if
             fine tuning is desired.  See sseett oorriiggiinn and sseett ssiizzee for
             details of their usage.

             Example:
                   set multiplot
                   set size 0.4,0.4










   GNUPLOT 4.1                                                      186


                   set origin 0.1,0.1
                   plot sin(x)
                   set size 0.2,0.2
                   set origin 0.5,0.5
                   plot cos(x)
                   unset multiplot

             This displays a plot of cos(x) stacked above a plot of
             sin(x).

             sseett ssiizzee and sseett oorriiggiinn refer to the entire plotting area
             used for each plot.  Please also see sseett tteerrmm ssiizzee.  If
             you want to have the axes themselves line up, you can
             guarantee that the margins are the same size with the sseett
             mmaarrggiinn commands.  See sseett mmaarrggiinn for their use.  Note that
             the margin settings are absolute, in character units, so
             the appearance of the graph in the remaining space will
             depend on the screen size of the display device, e.g.,
             perhaps quite different on a video display and a printer.

             With the llaayyoouutt option you can generate simple multiplots
             without having to give the sseett ssiizzee and sseett oorriiggiinn com-
             mands before each plot:  Those are generated automati-
             cally, but can be overridden at any time.  With llaayyoouutt the
             display will be divided by a grid with <rows> rows and
             <cols> columns.  This grid is filled rows first or columns
             first depending on whether the corresponding option is
             given in the multiplot command.  The stack of plots can
             grow ddoowwnnwwaarrddss or uuppwwaarrddss.  Default is rroowwssffiirrsstt and ddoowwnn--
             wwaarrddss.

             Each plot can be scaled by ssccaallee and shifted with ooffffsseett;
             if the y-values for scale or offset are omitted, the x-
             value will be used.  uunnsseett mmuullttiipplloott will turn off the
             automatic layout and restore the values of sseett ssiizzee and
             sseett oorriiggiinn as they were before sseett mmuullttiipplloott llaayyoouutt.

             Example:
                   set size 1,1
                   set origin 0,0
                   set multiplot layout 3,2 columnsfirst scale 1.1,0.9
                   [ up to 6 plot commands here ]
                   unset multiplot

             The above example will produce 6 plots in 2 columns filled
             top to bottom, left to right.  Each plot will have a hori-
             zontal size of 1.1/2 and a vertical size of 0.9/3.

             See also multiplot demo (multiplt.dem)














   GNUPLOT 4.1                                                      187


             8844..4422..  MMxx22ttiiccss


             Minor tic marks along the x2 (top) axis are controlled by
             sseett mmxx22ttiiccss.  Please see sseett mmxxttiiccss.



             8844..4433..  MMxxttiiccss


             Minor tic marks along the x axis are controlled by sseett
             mmxxttiiccss.  They can be turned off with uunnsseett mmxxttiiccss.  Simi-
             lar commands control minor tics along the other axes.

             Syntax:
                   set mxtics {<freq> | default}
                   unset mxtics
                   show mxtics

             The same syntax applies to mmyyttiiccss, mmzzttiiccss, mmxx22ttiiccss,
             mmyy22ttiiccss and mmccbbttiiccss.

             <freq> is the number of sub-intervals (NOT the number of
             minor tics) between major tics (the default for a linear
             axis is either two or five depending on the major tics, so
             there are one or four minor tics between major tics).
             Selecting ddeeffaauulltt will return the number of minor ticks to
             its default value.

             If the axis is logarithmic, the number of sub-intervals
             will be set to a reasonable number by default (based upon
             the length of a decade).  This will be overridden if
             <freq> is given.  However the usual minor tics (2, 3, ...,
             8, 9 between 1 and 10, for example) are obtained by set-
             ting <freq> to 10, even though there are but nine sub-
             intervals.

             To set minor tics at arbitrary positions, use the
             ("<label>" <pos> <level>, ...) form of sseett
             {{xx||xx22||yy||yy22||zz}}ttiiccss with <label> empty and <level> set to 1.

             The sseett mm{{xx||xx22||yy||yy22||zz}}ttiiccss commands work only when there
             are uniformly spaced major tics.  If all major tics were
             placed explicitly by sseett {{xx||xx22||yy||yy22||zz}}ttiiccss, then minor tic
             commands are ignored.  Implicit major tics and explicit
             minor tics can be combined using sseett {{xx||xx22||yy||yy22||zz}}ttiiccss and
             sseett {{xx||xx22||yy||yy22||zz}}ttiiccss aadddd.

             Examples:
                   set xtics 0, 5, 10
                   set xtics add (7.5)
                   set mxtics 5










   GNUPLOT 4.1                                                      188


             Major tics at 0,5,7.5,10, minor tics at 1,2,3,4,6,7,8,9
                   set logscale y
                   set ytics format ""
                   set ytics 1e-6, 10, 1
                   set ytics add ("1" 1, ".1" 0.1, ".01" 0.01, "10^-3"
             0.001, \
                                  "10^-4" 0.0001)
                   set mytics 10
             Major tics with special formatting, minor tics at log
             positions

             By default, minor tics are off for linear axes and on for
             logarithmic axes.  They inherit the settings for aaxxiiss||bboorr--
             ddeerr and {{nnoo}}mmiirrrroorr specified for the major tics.  Please
             see sseett xxttiiccss for information about these.



             8844..4444..  MMyy22ttiiccss


             Minor tic marks along the y2 (right-hand) axis are con-
             trolled by sseett mmyy22ttiiccss.  Please see sseett mmxxttiiccss.



             8844..4455..  MMyyttiiccss


             Minor tic marks along the y axis are controlled by sseett
             mmyyttiiccss.  Please see sseett mmxxttiiccss.



             8844..4466..  MMzzttiiccss


             Minor tic marks along the z axis are controlled by sseett
             mmzzttiiccss.  Please see sseett mmxxttiiccss.



             8844..4477..  OObbjjeecctt


             The sseett oobbjjeecctt command defines a single object which will
             appear in all subsequent 2D plots. You may define as many
             objects as you like. Currently the supported object types
             are rreeccttaannggllee, cciirrccllee, eelllliippssee, and ppoollyyggoonn.  Rectangles
             inherit a default set of style properties (fill, color,
             border) from those set by the command sseett ssttyyllee rreeccttaannggllee,
             but each object can also be given individual style proper-
             ties. Circles, ellipses, and polygons  inherit the fill










   GNUPLOT 4.1                                                      189


             style from sseett ssttyyllee ffiillll.

             Syntax:
                 set object <index>
                     <object-type> <object-properties>
                     {front|back|behind} {fc|fillcolor <colorspec>} {fs
             <fillstyle>}
                     {default} {lw|linewidth <width>}

             <object-type> is either rreeccttaannggllee, eelllliippssee, cciirrccllee, or
             ppoollyyggoonn.  Each object type has its own set of characteris-
             tic properties.

             Setting ffrroonntt will draw the object in front of all plot
             elements, but behind any labels that are also marked
             ffrroonntt. Setting bbaacckk will place the object behind all plot
             curves and labels. Setting bbeehhiinndd will place the object
             behind everything including the axes and bbaacckk rectangles,
             thus
                 set object rectangle from screen 0,0 to screen 1,1
             behind
             can be used to provide a colored background for the entire
             graph or page.

             The fill color of the object is taken from the <color-
             spec>. ffiillllccoolloorr may be abbreviated ffcc.  The fill style is
             taken from <fillstyle>.  See ccoolloorrssppeecc and ffiillllssttyyllee.  If
             the keyword ddeeffaauulltt is given, these properties are inher-
             ited from the default settings at the time a plot is
             drawn. See sseett ssttyyllee rreeccttaannggllee.




                  8844..4477..11..  RReeccttaannggllee


                  Syntax:
                      set object <index> rectangle
                          {from <position> {to|rto} <position> |
                           center <position> size <w>,<h> |
                           at <position> size <w>,<h>}

                  The position of the rectangle may be specified by
                  giving the position of two diagonal corners (bottom
                  left and top right) or by giving the position of the
                  center followed by the width and the height.  In
                  either case the positions may be given in axis,
                  graph, or screen coordinates. See ccoooorrddiinnaatteess.  The
                  options aatt and cceenntteerr are synonyms.

                  Examples:
                      # Force the entire area enclosed by the axes to










   GNUPLOT 4.1                                                      190


                  have background color cyan
                      set object 1 rect from graph 0, graph 0 to graph
                  1, graph 1 back
                      set object 1 rect fc rgb "cyan" fillstyle solid
                  1.0

                      # Position a red square with lower left at 0,0
                  and upper right at 2,3
                      set object 2 rect from 0,0 to 2,3 fc lt 1

                      # Position an empty rectangle (no fill) with a
                  blue border
                      set object 3 rect from 0,0 to 2,3 fs empty border
                  rgb "blue"

                      # Return fill and color to the default style but
                  leave vertices unchanged
                      set object 2 rect default

                  Rectangle corners specified in screen coordinates may
                  extend beyond the edge of the current graph. Other-
                  wise the rectangle is clipped to fit in the graph.




                  8844..4477..22..  EElllliippssee


                  Syntax:
                      set object <index> ellipse {at|center} <position>
                  size <w>,<h>
                          {angle <orientation>} {units xy|xx|yy}
                          {<other-object-properties>}

                  The position of the ellipse is specified by giving
                  the center followed by the width and the height
                  (actually the major and minor axes). The keywords aatt
                  and cceenntteerr are synonyms.  The center position may be
                  given in axis, graph, or screen coordinates. See
                  ccoooorrddiinnaatteess. The major and minor axis lengths must be
                  given in axis coordinates.  The orientation of the
                  ellipse is specified by the angle between the hori-
                  zontal axis and the major diameter of the ellipse.
                  If no angle is given, the default ellipse orientation
                  will be used instead (see sseett ssttyyllee eelllliippssee).  The
                  uunniittss keyword controls the scaling of the axes of the
                  ellipse. uunniittss xxyy means that the major axis is inter-
                  preted in terms of units along the x axis, while the
                  minor axis in that of the y axis. uunniittss xxxx means that
                  both axes of the ellipses are scaled in the units of
                  the x axis, while uunniittss yyyy means that both axes are
                  in units of the y axis.  The default is xxyy or










   GNUPLOT 4.1                                                      191


                  whatever sseett ssttyyllee eelllliippssee uunniittss was set to.

                  NB: If the x and y axis scales are not equal, (e.g.
                  uunniittss xxyy is in effect) then the major/minor axis
                  ratio will no longer be correct after rotation.

                  Note that sseett oobbjjeecctt eelllliippssee ssiizzee <<22rr>>,,<<22rr>> does not
                  in general produce the same result as sseett oobbjjeecctt cciirr--
                  ccllee <<rr>>.  The circle radius is always interpreted in
                  terms of units along the x axis, and will always pro-
                  duce a circle even if the x and y axis scales are
                  different and even if the aspect ratio of your plot
                  is not 1.  If uunniittss is set to xxyy, then 'set object
                  ellipse' interprets the first <2r> in terms of x axis
                  units and the second <2r> in terms of y axis units.
                  This will only produce a circle if the x and y axis
                  scales are identical and the plot aspect ratio is 1.
                  On the other hand, if uunniittss is set to xxxx or yyyy, then
                  the diameters specified in the 'set object' command
                  will be interpreted in the same units, so the ellipse
                  will have the correct aspect ratio, and it will main-
                  tain its aspect ratio even if the plot is resized.




                  8844..4477..33..  CCiirrccllee


                  Syntax:
                      set object <index> circle {at|center} <position>
                  size <radius>
                          {arc [<begin>:<end>]}
                          {<other-object-properties>}

                  The position of the circle is specified by giving the
                  position of the center center followed by the radius.
                  The keywords aatt and cceenntteerr are synonyms.  The posi-
                  tion and radius may be given in x-axis, graph, or
                  canvas coordinates. See ccoooorrddiinnaatteess. In all cases the
                  radius is calculated relative to the horizontal scale
                  of the axis, graph, or canvas.  Any disparity between
                  the horizontal and vertical scaling will be corrected
                  for so that the result is always a circle.

                  By default a full circle is drawn. The optional qual-
                  ifier aarrcc specifies a starting angle and ending
                  angle, in degrees, for one arc of the circle.  The
                  arc is always drawn counterclockwise.














   GNUPLOT 4.1                                                      192


                  8844..4477..44..  PPoollyyggoonn


                  Syntax:
                      set object <index> polygon
                          from <position> to <position> ... {to <posi-
                  tion>}
                  or
                          from <position> rto <position> ... {rto
                  <position>}

                  The position of the polygon may be specified by giv-
                  ing the position of a sequence of vertices. These may
                  be given in axis, graph, or screen coordinates.  If
                  relative coordinates are used (rto) then the coordi-
                  nate type must match that of the previous vertex.
                  See ccoooorrddiinnaatteess.

                  Example:
                      set object 1 polygon from 0,0 to 1,1 to 2,0
                      set object 1 fc rgb "cyan" fillstyle solid 1.0
                  border lt -1




             8844..4488..  OOffffsseettss


             Offsets provide a mechanism to put an empty boundary
             around the data inside an autoscaled graph.  The offsets
             only affect the x1 and y1 axes, and only in 2D pplloott com-
             mands.

             Syntax:
                   set offsets <left>, <right>, <top>, <bottom>
                   unset offsets
                   show offsets

             Each offset may be a constant or an expression.  Each
             defaults to 0.  By default, the left and right offsets are
             given in units of the first x axis, the top and bottom
             offsets in units of the first y axis.  Alternatively, you
             may specify the offsets as a fraction of the total axis
             range by using the keyword "graph".  A positive offset
             expands the axis range in the specified direction, e.g., a
             positive bottom offset makes ymin more negative.  Negative
             offsets, while permitted, can have unexpected interactions
             with autoscaling and clipping.  To prevent the auto-scal-
             ing from further adjusting your axis ranges, it is useful
             to also specify "set auto fix".

             Example:










   GNUPLOT 4.1                                                      193


                   set auto fix
                   set offsets graph 0.05, 0, 2, 2
                   plot sin(x)

             This graph of sin(x) will have a y range [-3:3] because
             the function will be autoscaled to [-1:1] and the vertical
             offsets are each two.  The x range will be [-11:10]
             because the default is [-10:10] and it has been expanded
             to the left by 0.05 of that total range.



             8844..4499..  OOrriiggiinn


             The sseett oorriiggiinn command is used to specify the origin of a
             plotting surface (i.e., the graph and its margins) on the
             screen.  The coordinates are given in the ssccrreeeenn coordi-
             nate system (see ccoooorrddiinnaatteess for information about this
             system).

             Syntax:
                   set origin <x-origin>,<y-origin>



             8844..5500..  OOuuttppuutt


             By default, screens are displayed to the standard output.
             The sseett oouuttppuutt command redirects the display to the speci-
             fied file or device.

             Syntax:
                   set output {"<filename>"}
                   show output

             The filename must be enclosed in quotes.  If the filename
             is omitted, any output file opened by a previous invoca-
             tion of sseett oouuttppuutt will be closed and new output will be
             sent to STDOUT.  (If you give the command sseett oouuttppuutt ""SSTTDD--
             OOUUTT"", your output may be sent to a file named "STDOUT"!
             ["May be", not "will be", because some terminals, like xx1111
             or wwxxtt, ignore sseett oouuttppuutt.])

             When both sseett tteerrmmiinnaall and sseett oouuttppuutt are used together,
             it is safest to give sseett tteerrmmiinnaall first, because some ter-
             minals set a flag which is needed in some operating sys-
             tems.  This would be the case, for example, if the operat-
             ing system needs to know whether or not a file is to be
             formatted in order to open it properly.

             On machines with popen functions (Unix), output can be










   GNUPLOT 4.1                                                      194


             piped through a shell command if the first non-whitespace
             character of the filename is '|'.  For instance,

                   set output "|lpr -Plaser filename"
                   set output "|lp -dlaser filename"

             On MSDOS machines, sseett oouuttppuutt ""PPRRNN"" will direct the output
             to the default printer.  On VMS, output can be sent
             directly to any spooled device.  It is also possible to
             send the output to DECnet transparent tasks, which allows
             some flexibility.



             8844..5511..  PPaarraammeettrriicc


             The sseett ppaarraammeettrriicc command changes the meaning of pplloott
             (sspplloott) from normal functions to parametric functions.
             The command uunnsseett ppaarraammeettrriicc restores the plotting style
             to normal, single-valued expression plotting.

             Syntax:
                   set parametric
                   unset parametric
                   show parametric

             For 2D plotting, a parametric function is determined by a
             pair of parametric functions operating on a parameter.  An
             example of a 2D parametric function would be pplloott
             ssiinn((tt)),,ccooss((tt)), which draws a circle (if the aspect ratio
             is set correctly---see sseett ssiizzee).  ggnnuupplloott will display an
             error message if both functions are not provided for a
             parametric pplloott.

             For 3D plotting, the surface is described as x=f(u,v),
             y=g(u,v), z=h(u,v).  Therefore a triplet of functions is
             required.  An example of a 3D parametric function would be
             ccooss((uu))**ccooss((vv)),,ccooss((uu))**ssiinn((vv)),,ssiinn((uu)), which draws a sphere.
             ggnnuupplloott will display an error message if all three func-
             tions are not provided for a parametric sspplloott.

             The total set of possible plots is a superset of the sim-
             ple f(x) style plots, since the two functions can describe
             the x and y values to be computed separately.  In fact,
             plots of the type t,f(t) are equivalent to those produced
             with f(x) because the x values are computed using the
             identity function.  Similarly, 3D plots of the type
             u,v,f(u,v) are equivalent to f(x,y).

             Note that the order the parametric functions are specified
             is xfunction, yfunction (and zfunction) and that each
             operates over the common parametric domain.










   GNUPLOT 4.1                                                      195


             Also, the sseett ppaarraammeettrriicc function implies a new range of
             values.  Whereas the normal f(x) and f(x,y) style plotting
             assume an xrange and yrange (and zrange), the parametric
             mode additionally specifies a trange, urange, and vrange.
             These ranges may be set directly with sseett ttrraannggee, sseett
             uurraannggee, and sseett vvrraannggee, or by specifying the range on the
             pplloott or sspplloott commands.  Currently the default range for
             these parametric variables is [-5:5].  Setting the ranges
             to something more meaningful is expected.



             8844..5522..  PPlloott


             The sshhooww pplloott command shows the current plotting command
             as it results from the last pplloott and/or sspplloott and possible
             subsequent rreepplloott commands.

             In addition, the sshhooww pplloott aadddd22hhiissttoorryy command adds this
             current plot command into the hhiissttoorryy. It is useful if you
             have used rreepplloott to add more curves to the current plot
             and you want to edit the whole command now.



             8844..5533..  PPmm33dd


             pm3d is an sspplloott style for drawing palette-mapped 3d and
             4d data as color/gray maps and surfaces.  It uses an algo-
             rithm that allows plotting gridded as well as non-gridded
             data without preprocessing, even when the data scans do
             not have the same number of points.

             Syntax (the options can be given in any order):
                   set pm3d {
                              { at <position> }
                              { interpolate <steps/points in scan,
             between scans> }
                              { scansautomatic | scansforward | scans-
             backward | depthorder }
                              { flush { begin | center | end } }
                              { ftriangles | noftriangles }
                              { clip1in | clip4in }
                              { corners2color {
             mean|geomean|median|min|max|c1|c2|c3|c4 } }
                              { hidden3d {<linestyle>} | nohidden3d }
                              { implicit | explicit }
                              { map }
                            }
                   show pm3d
                   unset pm3d










   GNUPLOT 4.1                                                      196


             A pm3d color surface is drawn if the splot command speci-
             fies wwiitthh ppmm33dd, if the data or function ssttyyllee is set to
             pm3d globally, or if the pm3d mode is sseett ppmm33dd iimmpplliicciitt.
             In the latter two cases, the pm3d surface is draw in addi-
             tion to the mesh produced by the style specified in the
             plot command. E.g.
                   splot 'fred.dat' with lines, 'lola.dat' with lines
             would draw both a mesh of lines and a pm3d surface for
             each data set.  If the option eexxpplliicciitt is on (or iimmpplliicciitt
             is off) only plots specified by the wwiitthh ppmm33dd attribute
             are plotted with a pm3d surface, e.g.:
                   splot 'fred.dat' with lines, 'lola.dat' with pm3d
             would plot 'fred.dat' with lines (only) and 'lola.dat'
             with a pm3d surface.

             On gnuplot start-up, the mode is eexxpplliicciitt. For historical
             and compatibility reasons, the commands sseett ppmm33dd;; (i.e. no
             options) and sseett ppmm33dd aatt XX ......  (i.e.  aatt is the first
             option) change the mode to iimmpplliicciitt.  The command sseett
             ppmm33dd;; sets other options to their default state.

             If you set the default data or function style to ppmm33dd,
             e.g.:
                   set style data pm3d
             then the options iimmpplliicciitt and eexxpplliicciitt have no effect.

             Note that when plotting several plots, they are plotted in
             the order given on the command line. This can be of inter-
             est especially for filled surfaces which can overwrite and
             therefore hide part of earlier plots.

             The pm3d coloring can be drawn at any or all of three dif-
             ferent positions, ttoopp, bboottttoomm, or ssuurrffaaccee. See ppmm33dd ppoossii--
             ttiioonn.  The following command draws three color surfaces at
             different altitudes:
                   set border 4095
                   set pm3d at s
                   splot 10*x with pm3d at b, x*x-y*y, x*x+y*y with
             pm3d at t

             See also help for sseett ppaalleettttee, sseett ccbbrraannggee, sseett ccoolloorrbbooxx,
             and definitely the demo file ddeemmoo//ppmm33dd..ddeemm.




                  8844..5533..11..  AAllggoorriitthhmm



                  Let us first describe how a map/surface is drawn.
                  The input data come from an evaluated function or
                  from an sspplloott ddaattaa ffiillee.  Each surface consists of a










   GNUPLOT 4.1                                                      197


                  sequence of separate scans (isolines).  The pm3d
                  algorithm fills the region between two neighbouring
                  points in one scan with another two points in the
                  next scan by a gray (or color) according to z-values
                  (or according to an additional 'color' column, see
                  help for uussiinngg) of these 4 corners; by default the 4
                  corner values are averaged, but this can be changed
                  by the option ccoorrnneerrss22ccoolloorr.  In order to get a rea-
                  sonable surface, the neighbouring scans should not
                  cross and the number of points in the neighbouring
                  scans should not differ too much; of course, the best
                  plot is with scans having same number of points.
                  There are no other requirements (e.g. the data need
                  not be gridded).  Another advantage is that the pm3d
                  algorithm does not draw anything outside of the input
                  (measured or calculated) region.

                  Surface coloring works with the following input data:

                  1. splot of function or of data file with one or
                  three data columns: The gray/color scale is obtained
                  by mapping the averaged (or ccoorrnneerrss22ccoolloorr) z-coordi-
                  nate of the four corners of the above-specified quad-
                  rangle into the range [min_color_z,max_color_z] of
                  zzrraannggee or ccbbrraannggee providing a gray value in the range
                  [0:1].  This value can be used directly as the gray
                  for gray maps.  The normalized gray value can be fur-
                  ther mapped into a color---see sseett ppaalleettttee for the
                  complete description.

                  2. splot of data file with two or four data columns:
                  The gray/color value is obtained by using the last-
                  column coordinate instead of the z-value, thus allow-
                  ing the color and the z-coordinate be mutually inde-
                  pendent.  This can be used for 4d data drawing.

                  Other notes:

                  1. The term 'scan' referenced above is used more
                  among physicists than the term 'iso_curve' referenced
                  in gnuplot documentation and sources.  You measure
                  maps recorded one scan after another scan, that's
                  why.

                  2. The 'gray' or 'color' scale is a linear mapping of
                  a continuous variable onto a smoothly varying palette
                  of colors. The mapping is shown in a rectangle next
                  to the main plot. This documentation refers to this
                  as a "colorbox", and refers to the indexing variable
                  as lying on the colorbox axis.  See sseett ccoolloorrbbooxx, sseett
                  ccbbrraannggee.

                  3. To use pm3d coloring to generate a two-dimensional










   GNUPLOT 4.1                                                      198


                  plot rather than a 3D surface, use sseett vviieeww mmaapp or
                  sseett ppmm33dd mmaapp.



                  8844..5533..22..  PPoossiittiioonn


                  Color surface can be drawn at the base or top (then
                  it is a gray/color planar map) or at z-coordinates of
                  surface points (gray/color surface).  This is defined
                  by the aatt option with a string of up to 6 combina-
                  tions of bb, tt and ss. For instance, aatt bb plots at bot-
                  tom only, aatt sstt plots firstly surface and then top
                  map, while aatt bbssttbbsstt will never by seriously used.

                  Colored quadrangles are plotted one after another.
                  When plotting surfaces (aatt ss), the later quadrangles
                  overlap (overdraw) the previous ones.  (Gnuplot is
                  not virtual reality tool to calculate intersections
                  of filled polygon meshes.)  You may try to switch
                  between ssccaannssffoorrwwaarrdd and ssccaannssbbaacckkwwaarrdd to force the
                  first scan of the data to be plotted first or last.
                  The default is ssccaannssaauuttoommaattiicc where gnuplot makes a
                  guess about scans order.  On the other hand, the
                  ddeepptthhoorrddeerr option completely reorders the quadran-
                  gles. The rendering is performed after a depth sort-
                  ing, which allows to visualize even complicated sur-
                  faces; see ppmm33dd ddeepptthhoorrddeerr for more details.



                  8844..5533..33..  SSccaannoorrddeerr


                  By default the quadrangles making up a pm3d solid
                  surface are rendered in the order they are encoun-
                  tered along the surface grid points.  This order may
                  be controlled by the options ssccaannssaauuttoommaattiicc|ssccaannssffoorr--
                  wwaarrdd|ssccaannssbbaacckkwwaarrdd.  These scan options are not in
                  general compatible with hidden-surface removal.

                  If two successive scans do not have same number of
                  points, then it has to be decided whether to start
                  taking points for quadrangles from the beginning of
                  both scans (fflluusshh bbeeggiinn), from their ends (fflluusshh eenndd)
                  or to center them (fflluusshh cceenntteerr).  Note, that fflluusshh
                  ((cceenntteerr||eenndd)) are incompatible with ssccaannssaauuttoommaattiicc: if
                  you specify fflluusshh cceenntteerr or fflluusshh eenndd and ssccaannssaauuttoo--
                  mmaattiicc is set, it is silently switched to ssccaannssffoorr--
                  wwaarrdd.

                  If two subsequent scans do not have the same number










   GNUPLOT 4.1                                                      199


                  of points, the option ffttrriiaanngglleess specifies whether
                  color triangles are drawn at the scan tail(s) where
                  there are not enough points in either of the scan.
                  This can be used to draw a smooth map boundary.

                  Gnuplot does not do true hidden surface removal for
                  solid surfaces, but often it is sufficient to render
                  the component quadrangles in order from furthest to
                  closest.  This mode may be selected using the options
                        set pm3d depthorder hidden3d
                  The ddeepptthhoorrddeerr option orders the solid quadrangles;
                  the hhiiddddeenn33dd option similarly orders the bounding
                  lines (if drawn).  Note that the global option sseett
                  hhiiddddeenn33dd does not affect pm3d surfaces.




                  8844..5533..44..  CClliippppiinngg


                  Clipping with respect to x, y coordinates of quadran-
                  gles can be done in two ways.  cclliipp11iinn: all 4 points
                  of each quadrangle must be defined and at least 1
                  point of the quadrangle must lie in the x and y
                  ranges.  cclliipp44iinn: all 4 points of each quadrangle
                  must lie in the x and y ranges.




                  8844..5533..55..  CCoolloorr__aassssiiggnnmmeenntt


                  33 ccoolluummnnss ooff ddaattaa ((xx,,yy,,zz)):

                  The coloring setup as well as the color box drawing
                  are determined by sseett ppaalleettttee.  There can be only one
                  palette for the current plot.  Drawing of several
                  surfaces with different palettes can be achieved by
                  mmuullttiipplloott with fixed oorriiggiinn and ssiizzee; don't forget to
                  use sseett ppaalleettttee mmaaxxccoolloorrss when your terminal is run-
                  ning out of available colors.

                  There is a single gray/color value associated to each
                  drawn pm3d quadrangle (no smooth color change among
                  vertices).  The value is calculated from z-coordi-
                  nates from the surrounding corners according to ccoorr--
                  nneerrss22ccoolloorr <<ooppttiioonn>>.  The options 'mean' (default),
                  'geomean' and 'median' produce various kinds of sur-
                  face color smoothing, while options 'min' and 'max'
                  choose minimal or maximal value, respectively. This
                  may not be desired for pixel images or for maps with










   GNUPLOT 4.1                                                      200


                  sharp and intense peaks, in which case the options
                  'c1', 'c2', 'c3' or 'c4' can be used instead to
                  assign the quadrangle color based on the z-coordinate
                  of only one corner.  Some experimentation may be
                  needed to determine which corner corresponds to 'c1',
                  as the orientation depends on the drawing direction.
                  Because the pm3d algorithm does not extend the col-
                  ored surface outside the range of the input data
                  points, the 'c<j>' coloring options will result in
                  pixels along two edges of the grid not contributing
                  to the color of any quadrangle.  For example, apply-
                  ing the pm3d algorithm to the 4x4 grid of data points
                  in script ddeemmoo//ppmm33dd..ddeemm (please have a look) produces
                  only (4-1)x(4-1)=9 colored rectangles.

                  44 ccoolluummnnss ooff ddaattaa ((xx,,yy,,zz,,ccoolloorr)):

                  If a fourth column of data is provided, it is nor-
                  mally interpreted as a separate palette-mapped gray
                  value. The coloring of individual quadrangles works
                  as above, except that the color value is distinct
                  from the z value.  As a separate coloring option, the
                  fourth data column may provide instead an RGB color.
                  See rrggbbccoolloorr vvaarriiaabbllee. In this case the plotting com-
                  mand must be

                        splot ... using 1:2:3:4 with pm3d lc rgb vari-
                  able

                  Another drawing algorithm, which would draw quadran-
                  gles around a given node by taking corners from aver-
                  aged (x,y)-coordinates of its surrounding 4 nodes
                  while using node's color, could be implemented in the
                  future. This is already done for drawing images (2D
                  grids) via iimmaaggee and rrggbbiimmaaggee styles.

                  Notice that ranges of z-values and color-values for
                  surfaces are adjustable independently by sseett zzrraannggee,
                  sseett ccbbrraannggee, as well as sseett lloogg for z or cb.  Maps
                  can be adjusted by the cb-axis only; see also sseett
                  vviieeww mmaapp and sseett ccoolloorrbbooxx.



                  8844..5533..66..  HHiiddddeenn33dd


                  The option sseett ppmm33dd hhiiddddeenn33dd draws the bounding lines
                  of each quadrangle at the same time that the quadran-
                  gle itself is drawn. Normally it is used in conjunc-
                  tion with the ddeepptthhoorrddeerr option to achieve an approx-
                  imation to true hidden line removal.  This is far
                  more efficient than using the command sseett hhiiddddeenn33dd.










   GNUPLOT 4.1                                                      201


                  The command takes an optional linestyle controlling
                  the appearance of the bounding lines.  If the
                  linestyle parameter is negative, or omitted, then the
                  line properties given in the plot command are used.
                  Example of recommended usage:

                        set pm3d at s hidden3d depthorder
                        unset hidden3d
                        unset surf
                        splot x*x+y*y linecolor rgb "black" linewidth
                  0.5




                  8844..5533..77..  IInntteerrppoollaattee


                  The option iinntteerrppoollaattee mm,,nn will interpolate grid
                  points into a finer mesh, and color each quadrangle
                  appropriately.  For data files, this will smoothen
                  the color surface, and enhance spikes in a color sur-
                  face. For functions, interpolation makes little
                  sense, except to trade off precision for memory.  It
                  would usually make more sense to use ssaammpplleess and
                  iissoossaammpplleess when working with functions. For positive
                  m and n, each quadrangle or triangle is interpolated
                  m-times and n-times in the respective direction.  For
                  negative m and n, the interpolation frequency is cho-
                  sen so that there will be at least |m| and |n| points
                  drawn; you can consider this as a special gridding
                  function.  Zeros, i.e. iinntteerrppoollaattee 00,,00, will automat-
                  ically choose an optimal number of interpolated sur-
                  face points.



                  8844..5533..88..  DDeepprreeccaatteedd__ooppttiioonnss


                  There used to be an option {transparent|solid} to
                  this command.  Now you get the same effect from sseett
                  ggrriidd {{ffrroonntt||llaayyeerrddeeffaauulltt}}, respectively.

                  The command sseett ppmm33dd mmaapp is equivalent to sseett ppmm33dd aatt
                  bb; sseett vviieeww mmaapp; sseett ssttyyllee ddaattaa ppmm33dd; sseett ssttyyllee ffuunncc
                  ppmm33dd;.  It is used for backwards compatibility, when
                  sseett vviieeww mmaapp was not available.  Take care that you
                  properly use zzrraannggee and ccbbrraannggee for input data point
                  filtering and color range scaling, respectively; and
                  also sseett ((nnoo))ssuurrffaaccee seems to have a (side?) effect.












   GNUPLOT 4.1                                                      202


             8844..5544..  PPaalleettttee


             Palette is a color storage for use by ppmm33dd, filled color
             contours or polygons, color histograms, color gradient
             background, and whatever it is or it will be imple-
             mented...  Here it stands for a palette of smooth "contin-
             uous" colors or grays, but let's call it just a palette.

             Color palettes require terminal entries for filled color
             polygons and palettes of smooth colors, are currently
             available for terminals listed in help for sseett ppmm33dd. The
             range of color values are adjustable independently by sseett
             ccbbrraannggee and sseett lloogg ccbb. The whole color palette is visual-
             ized in the ccoolloorrbbooxx.

             Syntax:
                   set palette
                   set palette {
                              { gray | color }
                              { gamma <gamma> }
                              {   rgbformulae <r>,<g>,<b>
                                | defined { ( <gray1> <color1> {,
             <grayN> <colorN>}... ) }
                                | file '<filename>' {datafile-modi-
             fiers}
                                | functions <R>,<G>,<B>
                              }
                              { cubehelix {start <val>} {cycles <val>}
             {saturation <val>} }
                              { model { RGB | HSV | CMY | YIQ | XYZ } }
                              { positive | negative }
                              { nops_allcF | ps_allcF }
                              { maxcolors <maxcolors> }
                            }
                   show palette
                   show palette palette <n> {{float | int}}
                   show palette gradient
                   show palette fit2rgbformulae
                   show palette rgbformulae
                   show colornames

             sseett ppaalleettttee (i.e. without options) sets up the default
             values.  Otherwise, the options can be given in any order.
             sshhooww ppaalleettttee shows the current palette properties.

             sshhooww ppaalleettttee ggrraaddiieenntt displays the gradient defining the
             palette (if appropriate).  sshhooww ppaalleettttee rrggbbffoorrmmuullaaee prints
             the available fixed gray --> color transformation formu-
             lae.  sshhooww ccoolloorrnnaammeess prints the known color names.

             sshhooww ppaalleettttee ppaalleettttee <<nn>> prints to the screen or to the
             file given by sseett pprriinntt a table of RGB triplets calculated










   GNUPLOT 4.1                                                      203


             for the current palette settings and a palette having <n>
             discrete colors.  The default wide table can be limited to
             3 columns of r,g,b float values [0..1] or integer values
             [0..255] by options float or int, respectively.  This way,
             the current gnuplot color palette can be loaded into other
             imaging applications, for example Octave.  Additionally to
             this textual list of RGB table, you can use the tteesstt
             ppaalleettttee command to plot the R,G,B profiles for the current
             palette.

             The following options determine the coloring properties.

             Figure using this palette can be ggrraayy or ccoolloorr.  For
             instance, in ppmm33dd color surfaces the gray of each small
             spot is obtained by mapping the averaged z-coordinate of
             the 4 corners of surface quadrangles into the range
             [min_z,max_z] providing range of grays [0:1]. This value
             can be used directly as the gray for gray maps. The color
             map requires a transformation gray --> (R,G,B), i.e. a
             mapping [0:1] --> ([0:1],[0:1],[0:1]).

             Basically two different types of mappings can be used:
             Analytic formulae to convert gray to color, or discrete
             mapping tables which are interpolated.  ppaalleettttee rrggbbffoorrmmuu--
             llaaee and ppaalleettttee ffuunnccttiioonnss use analytic formulae whereas
             ppaalleettttee ddeeffiinneedd and ppaalleettttee ffiillee use interpolated tables.
             ppaalleettttee rrggbbffoorrmmuullaaee reduces the size of postscript output
             to a minimum.

             The command sshhooww ppaalleettttee ffiitt22rrggbbffoorrmmuullaaee finds the best
             matching sseett ppaalleettttee rrggbbffoorrmmuullaaee for the current sseett
             ppaalleettttee. Naturally, it makes sense to use it for non-rgb-
             formulae palettes. This command can be found useful mainly
             for external programs using the same rgbformulae defini-
             tion of palettes as gnuplot, like zimg (
                       http://zimg.sourceforge.net
             ).

             sseett ppaalleettttee ggrraayy switches to a gray only palette. sseett
             ppaalleettttee rrggbbffoorrmmuullaaee, sseett ppaalleettttee ddeeffiinneedd, sseett ppaalleettttee ffiillee
             and sseett ppaalleettttee ffuunnccttiioonnss switch to a color mapping. sseett
             ppaalleettttee ccoolloorr is an easy way to switch back from the gray
             palette to the last color mapping.

             Automatic gamma correction via sseett ppaalleettttee ggaammmmaa <<ggaammmmaa>>
             can be done for gray maps (sseett ppaalleettttee ggrraayy) and for the
             ccuubbeehheelliixx color palette schemes.  Gamma = 1 produces a
             linear ramp of intensity. See tteesstt ppaalleettttee.

             Many terminals support only discrete number of colors
             (e.g. 256 colors in gif).  After the default gnuplot line-
             type colors are allocated, the rest of the available col-
             ors are by default reserved for pm3d.  Thus a multiplot










   GNUPLOT 4.1                                                      204


             using multiple palettes could fail because the first
             palette has used all the available color positions.  You
             can mitigate this limitation by using sseett ppaalleettttee mmaaxxccooll--
             oorrss <<NN>> with a reasonably small value of N.  This option
             causes N discrete colors to be selected from a continuous
             palette sampled at equally spaced intervals.  If you want
             unequal spacing of N discrete colors, use sseett ppaalleettttee
             ddeeffiinneedd instead of a single continuous palette.

             RGB color space might not be the most useful color space
             to work in.  For that reason you may change the color
             space with mmooddeell to one of RRGGBB, HHSSVV, CCMMYY, YYIIQQ and XXYYZZ.
             Using color names for sseett ppaalleettttee ddeeffiinneedd tables and a
             color space other than RGB will result in funny colors.
             All explanation have been written for RGB color space, so
             please note, that RR can be HH, CC, YY, or XX, depending on the
             actual color space (GG and BB accordingly).

             All values for all color spaces are limited to [0,1].

             RGB stands for Red, Green and Blue;  CMY stands for Cyan,
             Magenta and Yellow; HSV stands for Hue, Saturation, and
             Value;  YIQ is the color model used by the U.S. Commercial
             Color Television Broadcasting, it is basically an RGB
             recoding with downward compatibility for black and white
             television; XYZ are the three primary colors of the color
             model defined by the 'Commission Internationale de
             l'Eclairage' (CIE).  For more information on color models
             see:
                       http://en.wikipedia.org/wiki/Color_space





                  8844..5544..11..  RRggbbffoorrmmuullaaee


                  For rrggbbffoorrmmuullaaee three suitable mapping functions have
                  to be chosen.  This is done via rrggbbffoorrmmuullaaee
                  <<rr>>,,<<gg>>,,<<bb>>.  The available mapping functions are
                  listed by sshhooww ppaalleettttee rrggbbffoorrmmuullaaee.  Default is
                  77,,55,,1155, some other examples are 33,,1111,,66, 2211,,2233,,33 or
                  33,,2233,,2211.  Negative numbers, like 33,,--1111,,--66, mean
                  inverted color (i.e.  1-gray passed into the formula,
                  see also ppoossiittiivvee and nneeggaattiivvee options below).

                  Some nice schemes in RGB color space
                     7,5,15   ... traditional pm3d (black-blue-red-yel-
                  low)
                     3,11,6   ... green-red-violet
                     23,28,3  ... ocean (green-blue-white); try also
                  all other permutations










   GNUPLOT 4.1                                                      205


                     21,22,23 ... hot (black-red-yellow-white)
                     30,31,32 ... color printable on gray (black-blue-
                  violet-yellow-white)
                     33,13,10 ... rainbow (blue-green-yellow-red)
                     34,35,36 ... AFM hot (black-red-yellow-white)

                  A full color palette in HSV color space
                     3,2,2    ... red-yellow-green-cyan-blue-magenta-
                  red

                  Please note that even if called rrggbbffoorrmmuullaaee the for-
                  mulas might actually determine the <H>,<S>,<V> or
                  <X>,<Y>,<Z> or ... color components as usual.

                  Use ppoossiittiivvee and nneeggaattiivvee to invert the figure col-
                  ors.

                  Note that it is possible to find a set of the best
                  matching rgbformulae for any other color scheme by
                  the command
                     show palette fit2rgbformulae



                  8844..5544..22..  DDeeffiinneedd


                  Gray-to-rgb mapping can be manually set by use of
                  ppaalleettttee ddeeffiinneedd: A color gradient is defined and used
                  to give the rgb values.  Such a gradient is a piece-
                  wise linear mapping from gray values in [0,1] to the
                  RGB space [0,1]x[0,1]x[0,1].  You must specify the
                  gray values and the corresponding RGB values between
                  which linear interpolation will be done.

                  Syntax:
                        set palette  defined { ( <gray1> <color1> {,
                  <grayN> <colorN>}... ) }

                  <grayX> are gray values which are mapped to [0,1] and
                  <colorX> are the corresponding rgb colors.  The color
                  can be specified in three different ways:

                       <color> :=  { <r> <g> <b> | '<color-name>' |
                  '#rrggbb' }

                  Either by three numbers (each in [0,1]) for red,
                  green and blue, separated by whitespace, or the name
                  of the color in quotes or X style color specifiers
                  also in quotes.  You may freely mix the three types
                  in a gradient definition, but the named color "red"
                  will be something strange if RGB is not selected as
                  color space.  Use sshhooww ccoolloorrnnaammeess for a list of known










   GNUPLOT 4.1                                                      206


                  color names.

                  Please note, that even if written as <r>, this might
                  actually be the <H> component in HSV color space or
                  <X> in CIE-XYZ space, or ...  depending on the
                  selected color model.

                  The <gray> values have to form an ascending sequence
                  of real numbers; the sequence will be automatically
                  rescaled to [0,1].

                  sseett ppaalleettttee ddeeffiinneedd (without a gradient definition in
                  braces) switches to RGB color space and uses a preset
                  full-spectrum color gradient.  Use sshhooww ppaalleettttee ggrraa--
                  ddiieenntt to display the gradient.

                  Examples:

                  To produce a gray palette (useless but instructive)
                  use:
                        set palette model RGB
                        set palette defined ( 0 "black", 1 "white" )

                  To produce a blue yellow red palette use (all equiva-
                  lent):
                        set palette defined ( 0 "blue", 1 "yellow", 2
                  "red" )
                        set palette defined ( 0 0 0 1, 1 1 1 0, 2 1 0 0
                  )
                        set palette defined ( 0 "#0000ff", 1 "#ffff00",
                  2 "#ff0000" )

                  To produce some rainbow-like palette use:
                        set palette defined ( 0 "blue", 3 "green", 6
                  "yellow", 10 "red" )

                  Full color spectrum within HSV color space:
                        set palette model HSV
                        set palette defined ( 0 0 1 1, 1 1 1 1 )
                        set palette defined ( 0 0 1 0, 1 0 1 1, 6
                  0.8333 1 1, 7 0.8333 0 1)

                  Approximate the default palette used by MATLAB:
                        set pal defined (1 '#00008f', 8 '#0000ff', 24
                  '#00ffff', \
                                         40 '#ffff00', 56 '#ff0000', 64
                  '#800000')

                  To produce a palette with only a few, equally-spaced
                  colors:
                        set palette model RGB maxcolors 4
                        set palette defined ( 0 "yellow", 1 "red" )











   GNUPLOT 4.1                                                      207


                  'Traffic light' palette (non-smooth color jumps at
                  gray = 1/3 and 2/3).
                        set palette model RGB
                        set palette defined (0 "dark-green", 1 "green",
                  \
                                             1 "yellow",     2 "dark-
                  yellow", \
                                             2 "red",        3 "dark-
                  red" )




                  8844..5544..33..  FFuunnccttiioonnss


                  Use sseett ppaalleettttee ffuunnccttiioonnss <<RReexxpprr>>,, <<GGeexxpprr>>,, <<BBeexxpprr>>
                  to define three formulae for the R(gray), G(gray) and
                  B(gray) mapping.  The three formulae may depend on
                  the variable ggrraayy which will take values in [0,1] and
                  should also produce values in [0,1].  Please note
                  that <Rexpr> might be a formula for the H-value if
                  HSV color space has been chosen (same for all other
                  formulae and color spaces).

                  Examples:

                  To produce a full color palette use:
                        set palette model HSV functions gray, 1, 1

                  A nice black to gold palette:
                        set palette model XYZ functions gray**0.35,
                  gray**0.5, gray**0.8

                  A gamma-corrected black and white palette
                        gamma = 2.2
                        color(gray) = gray**(1./gamma)
                        set palette model RGB functions color(gray),
                  color(gray), color(gray)




                  8844..5544..44..  CCuubbeehheelliixx


                  The "cubehelix" option defines a family of palettes
                  in which color (hue) varies along the standard color
                  wheel while at the same time the net intensity
                  increases monotonically as the gray value goes from 0
                  to 1.
                        D A Green (2011) http://arxiv.org/abs/1108.5083
                  ssttaarrtt defines the starting point along the color










   GNUPLOT 4.1                                                      208


                  wheel in radians.  ccyycclleess defines how many color
                  wheel cycles span the palette range.  Larger values
                  of ssaattuurraattiioonn produce more saturated color; satura-
                  tion > 1 may lead to clipping of the individual RGB
                  components and to intensity becoming non-monotonic.
                  The palette is also affected by sseett ppaalleettttee ggaammmmaa.
                  The default values are
                        set palette cubehelix start 0.5 cycles -1.5
                  saturation 1
                        set palette gamma 1.5




                  8844..5544..55..  FFiillee


                  sseett ppaalleettttee ffiillee is basically a sseett ppaalleettttee ddeeffiinneedd
                  ((<<ggrraaddiieenntt>>)) where <gradient> is read from a
                  datafile.  Either 4 columns (gray,R,G,B) or just
                  three columns (R,G,B) have to be selected via the
                  uussiinngg data file modifier.  In the three column case,
                  the line number will be used as gray.  The gray range
                  is automatically rescaled to [0,1].  The file is read
                  as a normal data file, so all datafile modifiers can
                  be used.  Please note, that RR might actually be e.g.
                  HH if HSV color space is selected.

                  As usual <filename> may be ''--'' which means that the
                  data follow the command inline and are terminated by
                  a single ee on a line of its own.

                  Use sshhooww ppaalleettttee ggrraaddiieenntt to display the gradient.

                  Examples:

                  Read in a palette of RGB triples each in range
                  [0,255]:
                        set palette file 'some-palette' using
                  ($1/255):($2/255):($3/255)

                  Equidistant rainbow (blue-green-yellow-red) palette:
                        set palette model RGB file "-"
                        0 0 1
                        0 1 0
                        1 1 0
                        1 0 0
                        e

                  Binary palette files are supported as well, see
                  bbiinnaarryy ggeenneerraall. Example: put 64 triplets of R,G,B
                  doubles into file palette.bin and load it by
                        set palette file "palette.bin" binary record=64










   GNUPLOT 4.1                                                      209


                  using 1:2:3





                  8844..5544..66..  GGaammmmaa ccoorrrreeccttiioonn


                  For gray mappings gamma correction can be turned on
                  by sseett ppaalleettttee ggaammmmaa <<ggaammmmaa>>.  <gamma> defaults to
                  1.5 which is quite suitable for most terminals.

                  The gamma correction is applied to the cubehelix
                  color palette family, but not to other palette color-
                  ing schemes. However, you may easily implement gamma
                  correction for explicit color functions.

                  Example:
                        set palette model RGB
                        set palette functions gray**0.64, gray**0.67,
                  gray**0.70

                  To use gamma correction with interpolated gradients
                  specify intermediate gray values with appropriate
                  colors.  Instead of

                        set palette defined ( 0 0 0 0, 1 1 1 1 )

                  use e.g.

                        set palette defined ( 0 0 0 0, 0.5 .73 .73 .73,
                  1 1 1 1 )

                  or even more intermediate points until the linear
                  interpolation fits the "gamma corrected" interpola-
                  tion well enough.




                  8844..5544..77..  PPoossttssccrriipptt


                  In order to reduce the size of postscript files, the
                  gray value and not all three calculated r,g,b values
                  are written to the file.  Therefore the analytical
                  formulae are coded directly in the postscript lan-
                  guage as a header just before the pm3d drawing, see
                  /g and /cF definitions.  Usually, it makes sense to
                  write therein definitions of only the 3 formulae
                  used.  But for multiplot or any other reason you may
                  want to manually edit the transformations directly in










   GNUPLOT 4.1                                                      210


                  the postscript file.  This is the default option
                  nnooppss__aallllccFF.  Using the option ppss__aallllccFF writes post-
                  script definitions of all formulae.  This you may
                  find interesting if you want to edit the postscript
                  file in order to have different palettes for differ-
                  ent surfaces in one graph.  Well, you can achieve
                  this functionality by mmuullttiipplloott with fixed oorriiggiinn and
                  ssiizzee.

                  If pm3d map has been plotted from gridded or almost
                  regular data with an output to a postscript file,
                  then it is possible to reduce the size of this post-
                  script file up to at about 50% by the enclosed awk
                  script ppmm33ddCCoommpprreessss..aawwkk.  This you may find  inter-
                  esting if you intend to keep the file for including
                  it into your publication or before downloading a very
                  large file into a slow printer. Usage:
                      awk -f pm3dCompress.awk thefile.ps >smaller-
                  file.ps

                  If pm3d map has been plotted from rectangular gridded
                  data with an output to a postscript file, then it is
                  possible to reduce the file size even more by the
                  enclosed awk script ppmm33ddCCoonnvveerrttTTooIImmaaggee..aawwkk.  Usage:
                      awk -f pm3dConvertToImage.awk <thefile.ps >small-
                  erfile.ps

                  You may manually change the postscript output from
                  gray to color and vice versa and change the defini-
                  tion of <maxcolors>.



             8844..5555..  PPooiinnttiinntteerrvvaallbbooxx


             The ppooiinnttiinntteerrvvaall property of line types is used in plot
             style lliinneessppooiinnttss.  A negative value of pointinterval,
             e.g. -N, means that point symbols are drawn only for every
             Nth point, and that a box (actually circle) behind each
             point symbol is blanked out by filling with the background
             color.  The command sseett ppooiinnttiinntteerrvvaallbbooxx controls the
             radius of this blanked-out region.  It is a multiplier for
             the default radius, which is equal to the point size.



             8844..5566..  PPooiinnttssiizzee


             The sseett ppooiinnttssiizzee command scales the size of the points
             used in plots.











   GNUPLOT 4.1                                                      211


             Syntax:
                   set pointsize <multiplier>
                   show pointsize

             The default is a multiplier of 1.0.  Larger pointsizes may
             be useful to make points more visible in bitmapped graph-
             ics.

             The pointsize of a single plot may be changed on the pplloott
             command.  See pplloott wwiitthh for details.

             Please note that the pointsize setting is not supported by
             all terminal types.



             8844..5577..  PPoollaarr


             The sseett ppoollaarr command changes the meaning of the plot from
             rectangular coordinates to polar coordinates.

             Syntax:
                   set polar
                   unset polar
                   show polar

             In polar coordinates, the dummy variable (t) is an angle.
             The default range of t is [0:2*pi], or, if degree units
             have been selected, to [0:360] (see sseett aanngglleess).

             The command uunnsseett ppoollaarr changes the meaning of the plot
             back to the default rectangular coordinate system.

             The sseett ppoollaarr command is not supported for ssppllootts.  See
             the sseett mmaappppiinngg command for similar functionality for
             ssppllootts.

             While in polar coordinates the meaning of an expression in
             t is really r = f(t), where t is an angle of rotation.
             The trange controls the domain (the angle) of the func-
             tion. The r, x and y ranges control the extent of the
             graph in the x and y directions.  Each of these ranges, as
             well as the rrange, may be autoscaled or set explicitly.
             For details, see sseett rrrraannggee and sseett xxrraannggee.

             Example:
                   set polar
                   plot t*sin(t)
                   set trange [-2*pi:2*pi]
                   set rrange [0:3]
                   plot t*sin(t)











   GNUPLOT 4.1                                                      212


             The first pplloott uses the default polar angular domain of 0
             to 2*pi.  The radius and the size of the graph are scaled
             automatically.  The second pplloott expands the domain, and
             restricts the size of the graph to the area within 3 units
             of the origin.  This has the effect of limiting x and y to
             [-3:3].

             You may want to sseett ssiizzee ssqquuaarree to have ggnnuupplloott try to
             make the aspect ratio equal to unity, so that circles look
             circular.  See also polar demos (polar.dem) and polar data
             plot (poldat.dem).



             8844..5588..  PPrriinntt


             The sseett pprriinntt command redirects the output of the pprriinntt
             command to a file.

             Syntax:
                   set print
                   set print "-"
                   set print "<filename>"
                   set print "<filename>" append
                   set print "|<shell_command>"

             Without "<filename>", the output file is restored to
             <STDERR>.  The <filename> "-" means <STDOUT>. The aappppeenndd
             flag causes the file to be opened in append mode.  A
             <filename> starting with "|" is opened as a pipe to the
             <shell_command> on platforms that support piping.



             8844..5599..  PPssddiirr


             The sseett ppssddiirr <<ddiirreeccttoorryy>> command controls the search path
             used by the postscript terminal to find prologue.ps and
             character encoding files.  You can use this mechanism to
             switch between different sets of locally-customized prolog
             files.  The search order is
                   1) The directory specified by `set psdir`, if any
                   2) The directory specified by environmental variable
             GNUPLOT_PS_DIR
                   3) A built-in header or one from the default system
             directory
                   4) Directories set by `set loadpath`














   GNUPLOT 4.1                                                      213


             8844..6600..  RRaaxxiiss


             The commands sseett rraaxxiiss and uunnsseett rraaxxiiss toggle whether the
             polar axis is drawn separately from grid lines and the x
             axis.  If the minimum of the current rrange is non-zero
             (and not autoscaled), then a white circle is drawn at the
             center of the polar plot to indicate that the plot lines
             and axes do not reach 0.  The axis line is drawn using the
             same line type as the plot border.  See ppoollaarr, rrrraannggee,
             rrttiiccss, sseett ggrriidd.



             8844..6611..  RRmmaarrggiinn


             The command sseett rrmmaarrggiinn sets the size of the right margin.
             Please see sseett mmaarrggiinn for details.



             8844..6622..  RRrraannggee


             The sseett rrrraannggee command sets the range of the radial coor-
             dinate for a graph in polar mode.  This has the effect of
             setting both xrange and yrange as well.  The resulting
             xrange and yrange are both [-(rmax-rmin) : +(rmax-rmin)].
             However if you later change the x or y range, for example
             by zooming, this does not change rrange, so data points
             continue to be clipped against rrange.  Autoscaling of
             rmin always results in rmin = 0.



             8844..6633..  RRttiiccss


             The sseett rrttiiccss command places tics along the polar axis.
             These will only be shown in polar plot mode.  The tics and
             labels are drawn to the right of the origin. The mmiirrrroorr
             keyword causes them to be drawn also to the left of the
             origin. See ppoollaarr, and see sseett xxttiiccss for discussion of
             other keywords.



             8844..6644..  SSaammpplleess


             The sampling rate of functions, or for interpolating data,
             may be changed by the sseett ssaammpplleess command.










   GNUPLOT 4.1                                                      214


             Syntax:
                   set samples <samples_1> {,<samples_2>}
                   show samples

             By default, sampling is set to 100 points.  A higher sam-
             pling rate will produce more accurate plots, but will take
             longer.  This parameter has no effect on data file plot-
             ting unless one of the interpolation/approximation options
             is used.  See pplloott ssmmooootthh re 2D data and sseett ccnnttrrppaarraamm and
             sseett ddggrriidd33dd re 3D data.

             When a 2D graph is being done, only the value of <sam-
             ples_1> is relevant.

             When a surface plot is being done without the removal of
             hidden lines, the value of samples specifies the number of
             samples that are to be evaluated for the isolines.  Each
             iso-v line will have <sample_1> samples and each iso-u
             line will have <sample_2> samples.  If you only specify
             <samples_1>, <samples_2> will be set to the same value as
             <samples_1>.  See also sseett iissoossaammpplleess.



             8844..6655..  SSiizzee


             Syntax:
                   set size {{no}square | ratio <r> | noratio}
             {<xscale>,<yscale>}
                   show size

             The <xscale> and <yscale> values are scale factors for the
             size of the plot, which includes the graph, labels, and
             margins.

             Important note:
                   In earlier versions of gnuplot, some terminal types
             used the values from
                   `set size` to control also the size of the output
             canvas; others did not.
                   In version 4.6 almost all terminals now follow the
             following convention:

             sseett tteerrmm <<tteerrmmiinnaall__ttyyppee>> ssiizzee <<XXXX>>,, <<YYYY>> controls the size
             of the output file, or ccaannvvaass. Please see individual ter-
             minal documentation for allowed values of the size parame-
             ters.  By default, the plot will fill this canvas.

             sseett ssiizzee <<XXXX>>,, <<YYYY>> scales the plot itself relative to the
             size of the canvas.  Scale values less than 1 will cause
             the plot to not fill the entire canvas.  Scale values
             larger than 1 will cause only a portion of the plot to fit










   GNUPLOT 4.1                                                      215


             on the canvas.  Please be aware that setting scale values
             larger than 1 may cause problems on some terminal types.

             rraattiioo causes ggnnuupplloott to try to create a graph with an
             aspect ratio of <r> (the ratio of the y-axis length to the
             x-axis length) within the portion of the plot specified by
             <xscale> and <yscale>.

             The meaning of a negative value for <r> is different.  If
             <r>=-1, gnuplot tries to set the scales so that the unit
             has the same length on both the x and y axes.  This is
             equivalent to sseett vviieeww eeqquuaall xxyy.  See sseett vviieeww eeqquuaall.  If
             <r>=-2, the unit on y has twice the length of the unit on
             x, and so on.

             The success of ggnnuupplloott in producing the requested aspect
             ratio depends on the terminal selected.  The graph area
             will be the largest rectangle of aspect ratio <r> that
             will fit into the specified portion of the output (leaving
             adequate margins, of course).

             ssqquuaarree is a synonym for rraattiioo 11.

             Both nnoorraattiioo and nnoossqquuaarree return the graph to the default
             aspect ratio of the terminal, but do not return <xscale>
             or <yscale> to their default values (1.0).

             rraattiioo and ssqquuaarree have no effect on 3D plots, but do affect
             3D projections created using sseett vviieeww mmaapp.  See also sseett
             vviieeww eeqquuaall, which forces the x and y axes of a 3D onto the
             same scale.

             Examples:

             To set the size so that the plot fills the available can-
             vas:
                   set size 1,1

             To make the graph half size and square use:
                   set size square 0.5,0.5

             To make the graph twice as high as wide use:
                   set size ratio 2




             8844..6666..  SSttyyllee


             Default plotting styles are chosen with the sseett ssttyyllee ddaattaa
             and sseett ssttyyllee ffuunnccttiioonn commands.  See pplloott wwiitthh for infor-
             mation about how to override the default plotting style










   GNUPLOT 4.1                                                      216


             for individual functions and data sets.  See pplloottttiinngg
             ssttyylleess for a complete list of styles.

             Syntax:
                   set style function <style>
                   set style data <style>
                   show style function
                   show style data

             Default styles for specific plotting elements may also be
             set.

             Syntax:
                   set style arrow <n> <arrowstyle>
                   set style fill <fillstyle>
                   set style histogram <histogram style options>
                   set style line <n> <linestyle>

             If ggnnuupplloott was built with the support of objects, then the
             following options are also available:

             Syntax:
                   set style rectangle <object options> <linestyle>
             <fillstyle>
                   set style circle radius <size>
                   set style ellipse size <size> units {xy|xx|yy}





                  8844..6666..11..  SSeett ssttyyllee aarrrrooww


                  Each terminal has a default set of arrow and point
                  types, which can be seen by using the command tteesstt.
                  sseett ssttyyllee aarrrrooww defines a set of arrow types and
                  widths and point types and sizes so that you can
                  refer to them later by an index instead of repeating
                  all the information at each invocation.

                  Syntax:
                        set style arrow <index> default
                        set style arrow <index> {nohead | head | heads}
                                                {size
                  <length>,<angle>{,<backangle>}}
                                                {filled | empty |
                  nofilled}
                                                {front | back}
                                                { {linestyle | ls
                  <line_style>}
                                                  | {linetype | lt
                  <line_type>}










   GNUPLOT 4.1                                                      217


                                                    {linewidth | lw
                  <line_width} }
                        unset style arrow
                        show style arrow

                  <index> is an integer that identifies the arrowstyle.

                  If ddeeffaauulltt is given all arrow style parameters are
                  set to their default values.

                  If the linestyle <index> already exists, only the
                  given parameters are changed while all others are
                  preserved.  If not, all undefined values are set to
                  the default values.

                  Specifying nnoohheeaadd produces arrows drawn without a
                  head---a line segment.  This gives you yet another
                  way to draw a line segment on the plot.  By default,
                  arrows have one head. Specifying hheeaaddss draws arrow
                  heads on both ends of the line.

                  Head size can be controlled by ssiizzee <<lleennggtthh>>,,<<aannggllee>>
                  or ssiizzee <<lleennggtthh>>,,<<aannggllee>>,,<<bbaacckkaannggllee>>, where <<lleennggtthh>>
                  defines length of each branch of the arrow head and
                  <<aannggllee>> the angle (in degrees) they make with the
                  arrow.  <<LLeennggtthh>> is in x-axis units; this can be
                  changed by ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr
                  before the <length>;  see ccoooorrddiinnaatteess for details.
                  <<BBaacckkaannggllee>> only takes effect when ffiilllleedd or eemmppttyy is
                  also used.  Then, <<bbaacckkaannggllee>> is the angle (in
                  degrees) the back branches make with the arrow (in
                  the same direction as <<aannggllee>>).  The ffiigg terminal has
                  a restricted backangle function. It supports three
                  different angles. There are two thresholds: Below 70
                  degrees, the arrow head gets an indented back angle.
                  Above 110 degrees, the arrow head has an acute back
                  angle. Between these thresholds, the back line is
                  straight.

                  Specifying ffiilllleedd produces filled arrow heads (if
                  heads are used).  Filling is supported on filled-
                  polygon capable terminals, see help of ppmm33dd for their
                  list, otherwise the arrow heads are closed but not
                  filled.  The same result (closed but not filled arrow
                  head) is reached by specifying eemmppttyy.  Further, fill-
                  ing and outline is obviously not supported on termi-
                  nals drawing arrows by their own specific routines,
                  like mmeettaaffoonntt, mmeettaappoosstt, llaatteexx or ttggiiff.

                  The line style may be selected from a user-defined
                  list of line styles (see sseett ssttyyllee lliinnee) or may be
                  defined here by providing values for <<lliinnee__ttyyppee>> (an
                  index from the default list of styles) and/or










   GNUPLOT 4.1                                                      218


                  <<lliinnee__wwiiddtthh>> (which is a  multiplier for the default
                  width).

                  Note, however, that if a user-defined line style has
                  been selected, its properties (type and width) cannot
                  be altered merely by issuing another sseett ssttyyllee aarrrrooww
                  command with the appropriate index and lltt or llww.

                  If ffrroonntt is given, the arrows are written on top of
                  the graphed data. If bbaacckk is given (the default), the
                  arrow is written underneath the graphed data.  Using
                  ffrroonntt will prevent a arrow from being obscured by
                  dense data.

                  Examples:

                  To draw an arrow without an arrow head and double
                  width, use:
                        set style arrow 1 nohead lw 2
                        set arrow arrowstyle 1

                  See also sseett aarrrrooww for further examples.




                  8844..6666..22..  BBooxxpplloott


                  The sseett ssttyyllee bbooxxpplloott command allows you to change
                  the layout of plots created using the bbooxxpplloott plot
                  style.

                  Syntax:
                        set style boxplot {range <r> | fraction <f>}
                                          {{no}outliers} {pointtype
                  <p>}
                                          {candlesticks | financebars}
                                          {separation <x>}
                                          {labels off | auto | x | x2}
                                          {sorted | unsorted}

                  The box in the boxplot always spans the range of val-
                  ues from the first quartile to the third quartile of
                  the data points.  The limit of the whiskers that
                  extend from the box can be controlled in two differ-
                  ent ways. By default the whiskers extend from each
                  end of the box for a range equal to 1.5 times the
                  interquartile range (i.e. the vertical height of the
                  box proper).  Each whisker is truncated back toward
                  the median so that it terminates at a y value belong-
                  ing to some point in the data set. Since there may be
                  no point whose value is exactly 1.5 times the










   GNUPLOT 4.1                                                      219


                  interquartile distance, the whisker may be shorter
                  than its nominal range.  This default corresponds to
                        set style boxplot range 1.5

                  Alternatively, you can specify the fraction of the
                  total number of points that the whiskers should span.
                  In this case the range is extended symmetrically from
                  the median value until it encompasses the requested
                  fraction of the data set.  Here again each whisker is
                  constrained to end at a point in the data set.  To
                  span 95% of the points in the set
                        set style boxplot fraction 0.95

                  Any points that lie outside the range of the whiskers
                  are considered outliers.  By default these are drawn
                  as individual circles (pointtype 7).  The option
                  nnoooouuttlliieerrss disables this.

                  By default boxplots are drawn in a style similar to
                  candlesticks, but you have the option of using
                  instead a style similar to finance bars.

                  If the using specification for a boxplot contains a
                  fourth column, the values in that column will be
                  interpreted as the discrete leveles of a factor vari-
                  able.  In this case more than one boxplots may be
                  drawn, as many as the number of levels of the factor
                  variable.  These boxplots will be drawn next to each
                  other, the distance between them is 1.0 by default
                  (in x-axis units).  This distance can be changed by
                  the option sseeppaarraattiioonn.

                  The llaabbeellss option governs how and where these box-
                  plots (each representing a part of the dataset) are
                  labeled.  By default the value of the factor is put
                  as a tick label on the horizontal axis -- x or x2,
                  depending on which one is used for the plot itself.
                  This setting corresponds to option llaabbeellss aauuttoo.  The
                  labels can be forced to use either of the x or x2
                  axes -- options llaabbeellss xx and llaabbeellss xx22, respectively
                  --, or they can be turned off altogether with the
                  option llaabbeellss ooffff.

                  By default the boxplots corresponding to different
                  levels of the factor variable are not sorted; they
                  will be drawn in the same order the levels are
                  encountered in the data file. This behavior corre-
                  sponds to the uunnssoorrtteedd option. If the ssoorrtteedd option
                  is active, the levels are first sorted alphabeti-
                  cally, and the boxplots are drawn in the sorted
                  order.

                  The sseeppaarraattiioonn, llaabbeellss, ssoorrtteedd and uunnssoorrtteedd option










   GNUPLOT 4.1                                                      220


                  only have an effect if a fourth column is given the
                  plot specification.

                  See bbooxxpplloott, ccaannddlleessttiicckkss, ffiinnaanncceebbaarrss.




                  8844..6666..33..  SSeett ssttyyllee ddaattaa


                  The sseett ssttyyllee ddaattaa command changes the default plot-
                  ting style for data plots.

                  Syntax:
                        set style data <plotting-style>
                        show style data

                  See pplloottttiinngg ssttyylleess for the choices.  If no choice is
                  given, the choices are listed.  sshhooww ssttyyllee ddaattaa shows
                  the current default data plotting style.



                  8844..6666..44..  SSeett ssttyyllee ffiillll


                  The sseett ssttyyllee ffiillll command is used to set the default
                  style of the plot elements in plots with boxes, his-
                  tograms, candlesticks and filledcurves.  This default
                  can be superseded by fillstyles attached to individ-
                  ual plots.  See also 'set style rectangle'.

                  Syntax:
                        set style fill {empty
                                        | {transparent} solid {<den-
                  sity>}
                                        | {transparent} pattern {<n>}}
                                       {border {lt} {lc <colorspec>} |
                  noborder}

                  The default fillstyle is eemmppttyy.

                  The ssoolliidd option causes filling with a solid color,
                  if the terminal supports that. The <density> parame-
                  ter specifies the intensity of the fill color. At a
                  <density> of 0.0, the box is empty, at <density> of
                  1.0, the inner area is of the same color as the cur-
                  rent linetype.  Some terminal types can vary the den-
                  sity continuously; others implement only a few levels
                  of partial fill.  If no <density> parameter is given,
                  it defaults to 1.











   GNUPLOT 4.1                                                      221


                  The ppaatttteerrnn option causes filling to be done with a
                  fill pattern supplied by the terminal driver.  The
                  kind and number of available fill patterns depend on
                  the terminal driver.  If multiple datasets using
                  filled boxes are plotted, the pattern cycles through
                  all available pattern types, starting from pattern
                  <n>, much as the line type cycles for multiple line
                  plots.

                  The eemmppttyy option causes filled boxes not to be
                  filled. This is the default.

                  By default, bboorrddeerr, the box is bounded by a solid
                  line of the current linetype. bboorrddeerr <<ccoolloorrssppeecc>>
                  allows you to change the color of the border.  nnoobboorr--
                  ddeerr specifies that no bounding lines are drawn.




                       8844..6666..44..11..  SSeett ssttyyllee ffiillll ttrraannssppaarreenntt


                       Some terminals support the attribute ttrraannssppaarreenntt
                       for filled areas.  In the case of transparent
                       solid fill areas, the ddeennssiittyy parameter is
                       interpreted as an alpha value; that is, density
                       0 is fully transparent, density 1 is fully
                       opaque.  In the case of transparent pattern
                       fill, the background of the pattern is either
                       fully transparent or fully opaque.




                          +---------------------+
                          |Terminal   solid     |
                          +---------------------+
                          |  gif      no        |
                          |  jpeg     yes       |
                          |  pdf      yes       |
                          |  png      TrueColor |
                          |  post     no        |
                          |  svg      yes       |
                          |  win      yes       |
                          |  wxt      yes       |
                          |  x11      no        |
                          +---------------------+
                          +---------------------+














   GNUPLOT 4.1                                                      222


   Note that there may be additional limitations on the creation or
   viewing of graphs containing transparent fill areas.  For example,
   the png terminal can only use transparent fill if the "truecolor"
   option is set.  Some pdf viewers may not correctly display the fill
   areas even if they are correctly described in the pdf file.
   Ghostscript/gv does not correctly display pattern-fill areas even
   though actual PostScript printers generally have no problem.



                  8844..6666..55..  SSeett ssttyyllee ffuunnccttiioonn


                  The sseett ssttyyllee ffuunnccttiioonn command changes the default
                  plotting style for function plots (e.g. lines,
                  points, filledcurves).  See pplloottttiinngg ssttyylleess.

                  Syntax:
                        set style function <plotting-style>
                        show style function



                  8844..6666..66..  SSeett ssttyyllee iinnccrreemmeenntt


                  NNoottee:  This command has been deprecated.  Instead
                  please use the newer command sseett lliinneettyyppee, which
                  redefines the linetypes themselves rather than
                  searching for a suitable temporary line style to sub-
                  stitute.  See sseett lliinneettyyppee

                  Syntax:
                        set style increment {default|userstyles}
                        show style increment

                  By default, successive plots within the same graph
                  will use successive linetypes from the default set
                  for the current terminal type.  However, choosing sseett
                  ssttyyllee iinnccrreemmeenntt uusseerr allows you to step through the
                  user-defined line styles rather than through the
                  default linetypes.

                  Example:

                        set style line 1 lw 2 lc rgb "gold"
                        set style line 2 lw 2 lc rgb "purple"
                        set style line 4 lw 1 lc rgb "sea-green"
                        set style increment user

                        plot f1(x), f2(x), f3(x), f4(x)

                  should plot functions f1, f2, f4 in your 3 newly










   GNUPLOT 4.1                                                      223


                  defined line styles.  If a user-defined line style is
                  not found then the corresponding default linetype is
                  used instead.  E.g. in the example above, f3(x) will
                  be plotted using the default linetype 3.




                  8844..6666..77..  SSeett ssttyyllee lliinnee


                  Each terminal has a default set of line and point
                  types, which can be seen by using the command tteesstt.
                  sseett ssttyyllee lliinnee defines a set of line types and widths
                  and point types and sizes so that you can refer to
                  them later by an index instead of repeating all the
                  information at each invocation.

                  Syntax:
                        set style line <index> default
                        set style line <index> {{linetype  | lt}
                  <line_type> | <colorspec>}
                                               {{linecolor | lc} <col-
                  orspec>}
                                               {{linewidth | lw}
                  <line_width>}
                                               {{pointtype | pt}
                  <point_type>}
                                               {{pointsize | ps}
                  <point_size>}
                                               {{pointinterval | pi}
                  <interval>}
                                               {palette}
                        unset style line
                        show style line

                  ddeeffaauulltt sets all line style parameters to those of
                  the linetype with that same index.

                  If the linestyle <index> already exists, only the
                  given parameters are changed while all others are
                  preserved.  If not, all undefined values are set to
                  the default values.

                  Line styles created by this mechanism do not replace
                  the default linetype styles; both may be used.  Line
                  styles are temporary. They are lost whenever you exe-
                  cute a rreesseett command.  To redefine the linetype
                  itself, please see sseett lliinneettyyppee.

                  The line and point types default to the index value.
                  The exact symbol that is drawn for that index value
                  may vary from one terminal type to another.










   GNUPLOT 4.1                                                      224


                  The line width and point size are multipliers for the
                  current terminal's default width and size (but note
                  that <point_size> here is unaffected by the multi-
                  plier given by the commandsseett ppooiinnttssiizzee).

                  The ppooiinnttiinntteerrvvaall controls the spacing between points
                  in a plot drawn with style lliinneessppooiinnttss.  The default
                  is 0 (every point is drawn). For example, sseett ssttyyllee
                  lliinnee NN ppii 33 defines a linestyle that uses pointtype
                  N, pointsize and linewidth equal to the current
                  defaults for the terminal, and will draw every 3rd
                  point in plots using wwiitthh lliinneessppooiinnttss.  A negative
                  value for the interval is treated the same as a posi-
                  tive value, except that some terminals will try to
                  interrupt the line where it passes through the point
                  symbol.

                  Not all terminals support the lliinneewwiiddtthh and ppooiinnttssiizzee
                  features; if not supported, the option will be
                  ignored.

                  Terminal-independent colors may be assigned using
                  either lliinneeccoolloorr <<ccoolloorrssppeecc>> or lliinneettyyppee <<ccoolloorrssppeecc>>,
                  abbreviated llcc or lltt.  This requires giving a RGB
                  color triple, a known palette color name, a frac-
                  tional index into the current palette, or a constant
                  value from the current mapping of the palette onto
                  cbrange.  See ccoolloorrss, ccoolloorrssppeecc, sseett ppaalleettttee, ccoolloorr--
                  nnaammeess, ccbbrraannggee.

                  sseett ssttyyllee lliinnee <<nn>> lliinneettyyppee <<lltt>> will set both a ter-
                  minal-dependent dot/dash pattern and color. The com-
                  mandssseett ssttyyllee lliinnee <<nn>> lliinneeccoolloorr <<ccoolloorrssppeecc>> or sseett
                  ssttyyllee lliinnee <<nn>> lliinneettyyppee <<ccoolloorrssppeecc>> will set a new
                  line color while leaving the existing dot-dash pat-
                  tern unchanged.

                  In 3d mode (sspplloott command), the special keyword
                  ppaalleettttee is allowed as a shorthand for "linetype
                  palette z".  The color value corresponds to the z-
                  value (elevation) of the splot, and varies smoothly
                  along a line or surface.

                  Examples: Suppose that the default lines for indices
                  1, 2, and 3 are red, green, and blue, respectively,
                  and the default point shapes for the same indices are
                  a square, a cross, and a triangle, respectively.
                  Then

                        set style line 1 lt 2 lw 2 pt 3 ps 0.5

                  defines a new linestyle that is green and twice the
                  default width and a new pointstyle that is a half-










   GNUPLOT 4.1                                                      225


                  sized triangle.  The commands

                        set style function lines
                        plot f(x) lt 3, g(x) ls 1

                  will create a plot of f(x) using the default blue
                  line and a plot of g(x) using the user-defined wide
                  green line.  Similarly the commands

                        set style function linespoints
                        plot p(x) lt 1 pt 3, q(x) ls 1

                  will create a plot of p(x) using the default trian-
                  gles connected by a red line and q(x) using small
                  triangles connected by a green line.

                        splot sin(sqrt(x*x+y*y))/sqrt(x*x+y*y) w l pal

                  creates a surface plot using smooth colors according
                  to ppaalleettttee. Note, that this works only on some termi-
                  nals. See also sseett ppaalleettttee, sseett ppmm33dd.

                        set style line 10 linetype 1 linecolor rgb
                  "cyan"

                  will assign linestyle 10 to be a solid cyan line on
                  any terminal that supports rgb colors.




                  8844..6666..88..  SSeett ssttyyllee cciirrccllee



                  Syntax:
                        set style circle {radius {graph|screen} <R>}

                  This command sets the default radius used in plot
                  style "with circles".  It applies to data plots with
                  only 2 columns of data (x,y) and to function plots.
                  The default is "set style circle radius graph 0.02".




                  8844..6666..99..  SSeett ssttyyllee rreeccttaannggllee



                  Rectangles defined with the sseett oobbjjeecctt command can
                  have individual styles.  However, if the object is
                  not assigned a private style then it inherits a










   GNUPLOT 4.1                                                      226


                  default that is taken from the sseett ssttyyllee rreeccttaannggllee
                  command.

                  Syntax:
                      set style rectangle {front|back} {lw|linewidth
                  <lw>}
                                          {fillcolor <colorspec>} {fs
                  <fillstyle>}

                  See ccoolloorrssppeecc and ffiillllssttyyllee.  ffiillllccoolloorr may be abbre-
                  viated as ffcc.

                  Examples:
                      set style rectangle back fc rgb "white" fs solid
                  1.0 border lt -1
                      set style rectangle fc linsestyle 3 fs pattern 2
                  noborder

                  The default values correspond to solid fill with the
                  background color and a black border.




                  8844..6666..1100..  SSeett ssttyyllee eelllliippssee



                  Syntax:
                        set style ellipse {units xx|xy|yy}
                                          {size {graph|screen} <a>,
                  {{graph|screen} <b>}}
                                          {angle <angle>}

                  This command governs whether the diameters of
                  ellipses are interpreted in the same units or not.
                  Default is xxyy, which means that the major diameter
                  (first axis) of ellipses will be interpreted in the
                  same units as the x (or x2) axis, while the minor
                  (second) diameter in those of the y (or y2) axis.  In
                  this mode the ratio of the ellipse axes depends on
                  the scales of the plot axes and aspect ratio of the
                  plot.  When set to xxxx or yyyy, both axes of all
                  ellipses will be interpreted in the same units.  This
                  means that the ratio of the axes of the plotted
                  ellipses will be correct even after rotation, but
                  either their vertical or horizontal extent will not
                  be correct.

                  This is a global setting that affects all ellipses,
                  both those defined as objects and those generated
                  with the pplloott command, however, the value of uunniittss
                  can also be redefined on a per-plot and per-object










   GNUPLOT 4.1                                                      227


                  basis.

                  It is also possible to set a default size for
                  ellipses with the ssiizzee keyword.  This default size
                  applies to data plots with only 2 columns of data
                  (x,y) and to function plots.  The two values are
                  interpreted as the major and minor diameters (as
                  opposed to semi-major and semi-minor axes) of the
                  ellipse.

                  The default is "set style ellipse size graph
                  0.05,0.03".

                  Last, but not least it is possible to set the default
                  orientation with the aannggllee keyword. The orientation,
                  which is defined as the angle between the major axis
                  of the ellipse and the plot's x axis, must be given
                  in degrees.

                  For defining ellipse objects, see sseett oobbjjeecctt eelllliippssee;
                  for the 2D plot style, see eelllliippsseess.




             8844..6677..  SSuurrffaaccee


             The command sseett ssuurrffaaccee controls the display of surfaces
             by sspplloott.

             Syntax:
                   set surface
                   unset surface
                   show surface

             The surface is drawn with the style specified by wwiitthh, or
             else the appropriate style, data or function.

             uunnsseett ssuurrffaaccee will cause sspplloott to not draw points or lines
             corresponding to any of the function or data file points.
             If you want to turn off the surface for an individual
             function or data file while leaving the others active, use
             the nnoossuurrffaaccee keyword in the sspplloott command.  Contours may
             still be drawn on the surface, depending on the sseett ccoonn--
             ttoouurr option.  The combination uunnsseett ssuurrffaaccee;; sseett ccoonnttoouurr
             bbaassee is useful for displaying contours on the grid base.
             See also sseett ccoonnttoouurr.















   GNUPLOT 4.1                                                      228


             8844..6688..  TTaabbllee


             When ttaabbllee mode is enabled, pplloott and sspplloott commands print
             out a multicolumn ASCII table of X Y {Z} R values rather
             than creating an actual plot on the current terminal.  The
             character R takes on one of three values: "i" if the point
             is in the active range, "o" if it is out-of-range, or "u"
             if it is undefined.  The data format is determined by the
             format of the axis labels (see sseett ffoorrmmaatt), and the col-
             umns are separated by single spaces.  This can be useful
             if you want to generate contours and then save them for
             further use, perhaps for plotting with pplloott;  see sseett ccoonn--
             ttoouurr for example.  The same method can be used to save
             interpolated data (see sseett ssaammpplleess and sseett ddggrriidd33dd).

             Syntax:
                   set table {"outfile"}
                   plot <whatever>
                   unset table

             Tabular output is written to the named file, if any, oth-
             erwise it is written to the current value of sseett oouuttppuutt.
             You must explicitly uunnsseett ttaabbllee in order to go back to
             normal plotting on the current terminal.



             8844..6699..  TTeerrmmiinnaall


             ggnnuupplloott supports many different graphics devices.  Use sseett
             tteerrmmiinnaall to tell ggnnuupplloott what kind of output to generate.
             Use sseett oouuttppuutt to redirect that output to a file or
             device.

             Syntax:
                   set terminal {<terminal-type> | push | pop}
                   show terminal

             If <terminal-type> is omitted, ggnnuupplloott will list the
             available terminal types.  <terminal-type> may be abbrevi-
             ated.

             If both sseett tteerrmmiinnaall and sseett oouuttppuutt are used together, it
             is safest to give sseett tteerrmmiinnaall first, because some termi-
             nals set a flag which is needed in some operating systems.

             Some terminals have many additional options.  The options
             used by a previous invocation sseett tteerrmm <<tteerrmm>> <<ooppttiioonnss>> of
             a given <<tteerrmm>> are remembered, thus subsequent sseett tteerrmm
             <<tteerrmm>> does not reset them.  This helps in printing, for
             instance, when switching among different










   GNUPLOT 4.1                                                      229


             terminals---previous options don't have to be repeated.

             The command sseett tteerrmm ppuusshh remembers the current terminal
             including its settings while sseett tteerrmm ppoopp restores it.
             This is equivalent to ssaavvee tteerrmm and llooaadd tteerrmm, but without
             accessing the filesystem. Therefore they can be used to
             achieve platform independent restoring of the terminal
             after printing, for instance. After gnuplot's startup, the
             default terminal or that from ssttaarrttuupp file is pushed auto-
             matically. Therefore portable scripts can rely that sseett
             tteerrmm ppoopp restores the default terminal on a given platform
             unless another terminal has been pushed explicitly.

             For more information, see the ccoommpplleettee lliisstt ooff tteerrmmiinnaallss.




             8844..7700..  TTeerrmmooppttiioonn


             The sseett tteerrmmooppttiioonn command allows you to change the behav-
             iour of the current terminal without requiring a new sseett
             tteerrmmiinnaall command. Only one option can be changed per com-
             mand, and only a small number of options can be changed
             this way. Currently the only options accepted are

                  set termoption {no}enhanced
                  set termoption font "<fontname>{,<fontsize>}"
                  set termoption fontscale <scale>
                  set termoption {solid|dashed}
                  set termoption {linewidth <lw>}{lw <lw>}




             8844..7711..  TTiiccss


             Control of the major (labelled) tics on all axes at once
             is possible with the sseett ttiiccss command.

             Fine control of the major (labelled) tics on all axes at
             once is possible with the sseett ttiiccss command.  The tics may
             be turned off with the uunnsseett ttiiccss command, and may be
             turned on (the default state) with sseett ttiiccss.  Similar com-
             mands (by preceding 'tics' by the axis name) control the
             major tics on a single axis.

             Syntax:
                   set tics {axis | border} {{no}mirror}
                            {in | out} {scale {default | <major>
             {,<minor>}}}










   GNUPLOT 4.1                                                      230


                            {{no}rotate {by <ang>}} {offset <offset> |
             nooffset}
                            {left | right | center | autojustify}
                            { format "formatstring" } { font
             "name{,<size>}" }
                            { textcolor <colorspec> }
                   set tics {front | back}
                   unset tics
                   show tics

             The options in the first set above can be applied individ-
             ually to any or all axes, i.e., x, y, z, x2, y2, and cb.

             Set tics ffrroonntt or bbaacckk applies to all axes at once, but
             only for 2D plots (not splot).  It controls whether the
             tics are placed behind or in front of the plot elements,
             in the case that there is overlap.

             aaxxiiss or bboorrddeerr tells ggnnuupplloott to put the tics (both the
             tics themselves and the accompanying labels) along the
             axis or the border, respectively.  If the axis is very
             close to the border, the aaxxiiss option will move the tic
             labels to outside the border in case the border is printed
             (see sseett bboorrddeerr).  The relevant margin settings will usu-
             ally be sized badly by the automatic layout algorithm in
             this case.

             mmiirrrroorr tells ggnnuupplloott to put unlabelled tics at the same
             positions on the opposite border.  nnoommiirrrroorr does what you
             think it does.

             iinn and oouutt change the tic marks to be drawn inwards or
             outwards.

             With ssccaallee, the size of the tic marks can be adjusted. If
             <minor> is not specified, it is 0.5*<major>.  The default
             size 1.0 for major tics and 0.5 for minor tics is
             requested by ssccaallee ddeeffaauulltt.

             rroottaattee asks ggnnuupplloott to rotate the text through 90 degrees,
             which will be done if the terminal driver in use supports
             text rotation.  nnoorroottaattee cancels this. rroottaattee bbyy <<aanngg>>
             asks for rotation by <ang> degrees, supported by some ter-
             minal types.

             The defaults are bboorrddeerr mmiirrrroorr nnoorroottaattee for tics on the x
             and y axes, and bboorrddeerr nnoommiirrrroorr nnoorroottaattee for tics on the
             x2 and y2 axes.  For the z axis, the default is nnoommiirrrroorr.

             The <offset> is specified by either x,y or x,y,z, and may
             be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr
             to select the coordinate system. <offset> is the offset of
             the tics texts from their default positions, while the










   GNUPLOT 4.1                                                      231


             default coordinate system is cchhaarraacctteerr.  See ccoooorrddiinnaatteess
             for details. nnooooffffsseett switches off the offset.

             By default, tic labels are justified automatically depend-
             ing on the axis and rotation angle to produce aestheti-
             cally pleasing results. If this is not desired, justifica-
             tion can be overridden with an explicit lleefftt, rriigghhtt or
             cceenntteerr keyword. aauuttoojjuussttiiffyy restores the default behavior.

             sseett ttiiccss with no options restores to place tics inwards.
             Every other options are retained.

             See also sseett xxttiiccss for more control of major (labelled)
             tic marks and sseett mmxxttiiccss for control of minor tic marks.
             These commands provide control at a axis by axis basis.



             8844..7722..  TTiiccsslleevveell


             Deprecated. See sseett xxyyppllaannee.



             8844..7733..  TTiiccssccaallee


             The sseett ttiiccssccaallee command is deprecated, use sseett ttiiccss ssccaallee
             instead.



             8844..7744..  TTiimmeessttaammpp


             The command sseett ttiimmeessttaammpp places the time and date of the
             plot in the left margin.

             Syntax:
                   set timestamp {"<format>"} {top|bottom} {{no}rotate}
                                 {offset <xoff>{,<yoff>}} {font
             "<fontspec>"}
                   unset timestamp
                   show timestamp

             The format string allows you to choose the format used to
             write the date and time.  Its default value is what asc-
             time() uses: "%a %b %d %H:%M:%S %Y" (weekday, month name,
             day of the month, hours, minutes, seconds, four-digit
             year).  With ttoopp or bboottttoomm you can place the timestamp at
             the top or bottom of the left margin (default: bottom).
             rroottaattee lets you write the timestamp vertically, if your










   GNUPLOT 4.1                                                      232


             terminal supports vertical text.  The constants <xoff> and
             <yoff> are offsets that let you adjust the position more
             finely.  <font> is used to specify the font with which the
             time is to be written.

             The abbreviation ttiimmee may be used in place of ttiimmeessttaammpp.

             Example:
                   set timestamp "%d/%m/%y %H:%M" offset 80,-2 font
             "Helvetica"

             See sseett ttiimmeeffmmtt for more information about time format
             strings.



             8844..7755..  TTiimmeeffmmtt


             This command applies to timeseries where data are composed
             of dates/times.  It has no meaning unless the command sseett
             xxddaattaa ttiimmee is given also.

             Syntax:
                   set timefmt "<format string>"
                   show timefmt

             The string argument tells ggnnuupplloott how to read timedata
             from the datafile.  The valid formats are:




     +---------------------------------------------------------------+
     |Format   Explanation                                           |
     +---------------------------------------------------------------+
     |  %d     day of the month, 1--31                               |
     |  %m     month of the year, 1--12                              |
     |  %y     year, 0--99                                           |
     |  %Y     year, 4-digit                                         |
     |  %j     day of the year, 1--365                               |
     |  %H     hour, 0--24                                           |
     |  %M     minute, 0--60                                         |
     |  %s     seconds since the Unix epoch (1970-01-01 00:00 UTC)   |
     |  %S     second, integer 0--60 on output, (double) on input    |
     |  %b     three-character abbreviation of the name of the month |
     |  %B     name of the month                                     |
     +---------------------------------------------------------------+
     +---------------------------------------------------------------+














   GNUPLOT 4.1                                                      233


   Any character is allowed in the string, but must match exactly.  \t
   (tab) is recognized.  Backslash-octals (\nnn) are converted to char.
   If there is no separating character between the time/date elements,
   then %d, %m, %y, %H, %M and %S read two digits each.  If a decimal
   point immediately follows the field read by %S, the decimal and any
   following digits are interpreted as a fractional second.  %Y reads
   four digits. %j reads three digits.  %b requires three characters,
   and %B requires as many as it needs.

   Spaces are treated slightly differently.  A space in the string
   stands for zero or more whitespace characters in the file.  That is,
   "%H %M" can be used to read "1220" and "12     20" as well as "12
   20".

   Each set of non-blank characters in the timedata counts as one col-
   umn in the uussiinngg nn::nn specification.  Thus 1111::1111  2255//1122//7766  2211..00 con-
   sists of three columns.  To avoid confusion, ggnnuupplloott requires that
   you provide a complete uussiinngg specification if your file contains
   timedata.

   If the date format includes the day or month in words, the format
   string must exclude this text.  But it can still be printed with the
   "%a", "%A", "%b", or "%B" specifier.  ggnnuupplloott will determine the
   proper month and weekday from the numerical values.  See sseett ffoorrmmaatt
   for more details about these and other options for printing time
   data.

   When reading two-digit years with %y, values 69-99 refer to the 20th
   century, while values 00-68 refer to the 21st century.   NB: This is
   in accordance with the UNIX98 spec, but conventions vary widely and
   two-digit year values are inherently ambiguous.

   See also sseett xxddaattaa and ttiimmee//ddaattee for more information.

   Example:
         set timefmt "%d/%m/%Y\t%H:%M"
   tells ggnnuupplloott to read date and time separated by tab.  (But look
   closely at your data---what began as a tab may have been converted
   to spaces somewhere along the line; the format string must match
   what is actually in the file.)  See also time data demo.



             8844..7766..  TTiittllee


             The sseett ttiittllee command produces a plot title that is cen-
             tered at the top of the plot.  sseett ttiittllee is a special case
             of sseett llaabbeell.

             Syntax:
                   set title {"<title-text>"} {offset <offset>} {font
             "<font>{,<size>}"}










   GNUPLOT 4.1                                                      234


                             {{textcolor | tc} {<colorspec> | default}}
             {{no}enhanced}
                   show title

             If <offset> is specified by either x,y or x,y,z the title
             is moved by the given offset.  It may be preceded by
             ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr to select the
             coordinate system.  See ccoooorrddiinnaatteess for details.  By
             default, the cchhaarraacctteerr coordinate system is used.  For
             example, "sseett ttiittllee ooffffsseett 00,,--11" will change only the y
             offset of the title, moving the title down by roughly the
             height of one character.  The size of a character depends
             on both the font and the terminal.

             <font> is used to specify the font with which the title is
             to be written; the units of the font <size> depend upon
             which terminal is used.

             tteexxttccoolloorr <<ccoolloorrssppeecc>> changes the color of the text. <col-
             orspec> can be a linetype, an rgb color, or a palette map-
             ping. See help for ccoolloorrssppeecc and ppaalleettttee.

             nnooeennhhaanncceedd requests that the title not be processed by the
             enhanced text mode parser, even if enhanced text mode is
             currently active.

             sseett ttiittllee with no parameters clears the title.

             See ssyynnttaaxx for details about the processing of backslash
             sequences and the distinction between single- and double-
             quotes.



             8844..7777..  TTmmaarrggiinn


             The command sseett ttmmaarrggiinn sets the size of the top margin.
             Please see sseett mmaarrggiinn for details.



             8844..7788..  TTrraannggee


             The sseett ttrraannggee command sets the parametric range used to
             compute x and y values when in parametric or polar modes.
             Please see sseett xxrraannggee for details.















   GNUPLOT 4.1                                                      235


             8844..7799..  UUrraannggee


             The sseett uurraannggee and sseett vvrraannggee commands set the parametric
             ranges used to compute x, y, and z values when in sspplloott
             parametric mode.  Please see sseett xxrraannggee for details.



             8844..8800..  VVaarriiaabblleess


             The sshhooww vvaarriiaabblleess command lists the current value of
             user-defined and internal variables. Gnuplot internally
             defines variables whose names begin with GPVAL_, MOUSE_,
             FIT_, and TERM_.

             Syntax:
                   show variables      # show variables that do not
             begin with GPVAL_
                   show variables all  # show all variables including
             those beginning GPVAL_
                   show variables NAME # show only variables beginning
             with NAME




             8844..8811..  VVeerrssiioonn


             The sshhooww vveerrssiioonn command lists the version of gnuplot
             being run, its last modification date, the copyright hold-
             ers, and email addresses for the FAQ, the gnuplot-info
             mailing list, and reporting bugs--in short, the informa-
             tion listed on the screen when the program is invoked
             interactively.

             Syntax:
                   show version {long}

             When the lloonngg option is given, it also lists the operating
             system, the compilation options used when ggnnuupplloott was
             installed, the location of the help file, and (again) the
             useful email addresses.



             8844..8822..  VViieeww


             The sseett vviieeww command sets the viewing angle for ssppllootts.
             It controls how the 3D coordinates of the plot are mapped










   GNUPLOT 4.1                                                      236


             into the 2D screen space.  It provides controls for both
             rotation and scaling of the plotted data, but supports
             orthographic projections only.  It supports both 3D pro-
             jection or orthogonal 2D projection into a 2D plot-like
             map.

             Syntax:
                   set view <rot_x>{,{<rot_z>}{,{<scale>}{,<scale_z>}}}
                   set view map
                   set view {no}equal {xy|xyz}
                   show view

             where <rot_x> and <rot_z> control the rotation angles (in
             degrees) in a virtual 3D coordinate system aligned with
             the screen such that initially (that is, before the rota-
             tions are performed) the screen horizontal axis is x,
             screen vertical axis is y, and the axis perpendicular to
             the screen is z.  The first rotation applied is <rot_x>
             around the x axis.  The second rotation applied is <rot_z>
             around the new z axis.

             Command sseett vviieeww mmaapp is used to represent the drawing as a
             map. It can be used for ccoonnttoouurr plots, or for color ppmm33dd
             maps. In the latter, take care that you properly use
             zzrraannggee and ccbbrraannggee for input data point filtering and
             color range scaling, respectively.

             <rot_x> is bounded to the [0:180] range with a default of
             60 degrees, while <rot_z> is bounded to the [0:360] range
             with a default of 30 degrees.  <scale> controls the scal-
             ing of the entire sspplloott, while <scale_z> scales the z axis
             only.  Both scales default to 1.0.

             Examples:
                   set view 60, 30, 1, 1
                   set view ,,0.5

             The first sets all the four default values.  The second
             changes only scale, to 0.5.




                  8844..8822..11..  EEqquuaall__aaxxeess


                  The command sseett vviieeww eeqquuaall xxyy forces the unit length
                  of the x and y axes to be on the same scale, and
                  chooses that scale so that the plot will fit on the
                  page.  The command sseett vviieeww eeqquuaall xxyyzz additionally
                  sets the z axis scale to match the x and y axes; how-
                  ever there is no guarantee that the current z axis
                  range will fit within the plot boundary.  By default










   GNUPLOT 4.1                                                      237


                  all three axes are scaled independently to fill the
                  available area.

                  See also sseett xxyyppllaannee.



             8844..8833..  VVrraannggee


             The sseett uurraannggee and sseett vvrraannggee commands set the parametric
             ranges used to compute x, y, and z values when in sspplloott
             parametric mode.  Please see sseett xxrraannggee for details.



             8844..8844..  XX22ddaattaa


             The sseett xx22ddaattaa command sets data on the x2 (top) axis to
             timeseries (dates/times).  Please see sseett xxddaattaa.



             8844..8855..  XX22ddttiiccss


             The sseett xx22ddttiiccss command changes tics on the x2 (top) axis
             to days of the week.  Please see sseett xxddttiiccss for details.



             8844..8866..  XX22llaabbeell


             The sseett xx22llaabbeell command sets the label for the x2 (top)
             axis.  Please see sseett xxllaabbeell.



             8844..8877..  XX22mmttiiccss


             The sseett xx22mmttiiccss command changes tics on the x2 (top) axis
             to months of the year.  Please see sseett xxmmttiiccss for details.



             8844..8888..  XX22rraannggee


             The sseett xx22rraannggee command sets the horizontal range that
             will be displayed on the x2 (top) axis.  Please see sseett










   GNUPLOT 4.1                                                      238


             xxrraannggee for details.



             8844..8899..  XX22ttiiccss


             The sseett xx22ttiiccss command controls major (labelled) tics on
             the x2 (top) axis.  Please see sseett xxttiiccss for details.



             8844..9900..  XX22zzeerrooaaxxiiss


             The sseett xx22zzeerrooaaxxiiss command draws a line at the origin of
             the x2 (top) axis (y2 = 0).  For details, please see sseett
             zzeerrooaaxxiiss.



             8844..9911..  XXddaattaa


             This command sets the datatype on the x axis to time/date.
             A similar command does the same thing for each of the
             other axes.

             Syntax:
                   set xdata {time}
                   show xdata

             The same syntax applies to yyddaattaa, zzddaattaa, xx22ddaattaa, yy22ddaattaa
             and ccbbddaattaa.

             The ttiimmee option signals that the datatype is indeed
             time/date.  If the option is not specified, the datatype
             reverts to normal.

             See sseett ttiimmeeffmmtt to tell gnuplot how to read date or time
             data.  The time/date is converted to seconds from start of
             the century.  There is currently only one timefmt, which
             implies that all the time/date columns must conform to
             this format.  Specification of ranges should be supplied
             as quoted strings according to this format to avoid inter-
             pretation of the time/date as an expression.

             The function 'strftime' (type "man strftime" on unix to
             look it up) is used to print tic-mark labels.  ggnnuupplloott
             tries to figure out a reasonable format for this  unless
             the sseett ffoorrmmaatt xx ""ssttrriinngg"" has supplied something that does
             not look like a decimal format (more than one '%' or nei-
             ther %f nor %g).










   GNUPLOT 4.1                                                      239


             See also ttiimmee//ddaattee for more information.



             8844..9922..  XXddttiiccss


             The sseett xxddttiiccss commands converts the x-axis tic marks to
             days of the week where 0=Sun and 6=Sat.  Overflows are
             converted modulo 7 to dates.  sseett nnooxxddttiiccss returns the
             labels to their default values.  Similar commands do the
             same things for the other axes.

             Syntax:
                   set xdtics
                   unset xdtics
                   show xdtics

             The same syntax applies to yyddttiiccss, zzddttiiccss, xx22ddttiiccss,
             yy22ddttiiccss and ccbbddttiiccss.

             See also the sseett ffoorrmmaatt command.



             8844..9933..  XXllaabbeell


             The sseett xxllaabbeell command sets the x axis label.  Similar
             commands set labels on the other axes.

             Syntax:
                   set xlabel {"<label>"} {offset <offset>} {font
             "<font>{,<size>}"}
                              {textcolor <colorspec>} {{no}enhanced}
                              {rotate by <degrees> | rotate parallel |
             norotate}
                   show xlabel

             The same syntax applies to xx22llaabbeell, yyllaabbeell, yy22llaabbeell, zzllaa--
             bbeell and ccbbllaabbeell.

             If <offset> is specified by either x,y or x,y,z the label
             is moved by the given offset.  It may be preceded by
             ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr to select the
             coordinate system.  See ccoooorrddiinnaatteess for details.  By
             default, the cchhaarraacctteerr coordinate system is used.  For
             example, "sseett xxllaabbeell ooffffsseett --11,,00" will change only the x
             offset of the title, moving the label roughly one charac-
             ter width to the left.  The size of a character depends on
             both the font and the terminal.

             <font> is used to specify the font in which the label is










   GNUPLOT 4.1                                                      240


             written; the units of the font <size> depend upon which
             terminal is used.

             nnooeennhhaanncceedd requests that the label text not be processed
             by the enhanced text mode parser, even if enhanced text
             mode is currently active.

             To clear a label, put no options on the command line,
             e.g., "sseett yy22llaabbeell".

             The default positions of the axis labels are as follows:

             xlabel:  The x-axis label is centered below the bottom of
             the plot.

             ylabel:  The y-axis label is centered to the left of the
             plot, defaulting to either horizontal or vertical orienta-
             tion depending on the terminal type.

             zlabel: The z-axis label is centered along the z axis and
             placed in the space above the grid level.

             cblabel: The color box axis label is centered along the
             box and placed below or to the right according to horizon-
             tal or vertical color box gradient.

             y2label: The y2-axis label is placed to the right of the
             y2 axis.  The position is terminal-dependent in the same
             manner as is the y-axis label.

             x2label: The x2-axis label is placed above the plot but
             below the title.  It is also possible to create an x2-axis
             label by using new-line characters to make a multi-line
             plot title, e.g.,

                   set title "This is the title\n\nThis is the x2label"

             Note that double quotes must be used.  The same font will
             be used for both lines, of course.

             The orientation (rotation angle) of the x, x2, y and y2
             axis labels in 2D plots can be changed by specifying
             rroottaattee bbyy <<ddeeggrreeeess>>.  The orientation of the x and y axis
             labels in 3D plots defaults to horizontal but can be
             changed to run parallel to the axis by specifying rroottaattee
             ppaarraalllleell.

             If you are not satisfied with the default position of an
             axis label, use sseett llaabbeell instead--that command gives you
             much more control over where text is placed.

             Please see ssyynnttaaxx for further information about backslash
             processing and the difference between single- and double-










   GNUPLOT 4.1                                                      241


             quoted strings.



             8844..9944..  XXmmttiiccss


             The sseett xxmmttiiccss command converts the x-axis tic marks to
             months of the year where 1=Jan and 12=Dec.  Overflows are
             converted modulo 12 to months.  The tics are returned to
             their default labels by uunnsseett xxmmttiiccss.  Similar commands
             perform the same duties for the other axes.

             Syntax:
                   set xmtics
                   unset xmtics
                   show xmtics

             The same syntax applies to xx22mmttiiccss, yymmttiiccss, yy22mmttiiccss,
             zzmmttiiccss and ccbbmmttiiccss.

             See also the sseett ffoorrmmaatt command.



             8844..9955..  XXrraannggee


             The sseett xxrraannggee command sets the horizontal range that will
             be displayed.  A similar command exists for each of the
             other axes, as well as for the polar radius r and the
             parametric variables t, u, and v.

             Syntax:
                   set xrange { [{{<min>}:{<max>}}] {{no}reverse}
             {{no}writeback} }
                              | restore
                   show xrange

             where <min> and <max> terms are constants, expressions or
             an asterisk to set autoscaling.  See below for full
             autoscaling syntax.  If the data are time/date, you must
             give the range as a quoted string according to the sseett
             ttiimmeeffmmtt format.  Any value omitted will not be changed.

             The same syntax applies to yyrraannggee, zzrraannggee, xx22rraannggee,
             yy22rraannggee, ccbbrraannggee, rrrraannggee, ttrraannggee, uurraannggee and vvrraannggee.

             The rreevveerrssee option reverses the direction of the axis,
             e.g., sseett xxrraannggee [[00::11]] rreevveerrssee will produce an axis with 1
             on the left and 0 on the right.  This is identical to the
             axis produced by sseett xxrraannggee [[11::00]], of course.  rreevveerrssee is
             intended primarily for use with aauuttoossccaallee.










   GNUPLOT 4.1                                                      242


             Autoscaling:  If <min> (the same applies for correspond-
             ingly to <max>) is an asterisk "*" autoscaling is turned
             on.  The range in which autoscaling is being performed may
             be limited by a lower bound <lb> or an upper bound <ub> or
             both.  The syntax is
                   { <lb> < } * { < <ub> }
             For example,
                   0 < * < 200
             sets <lb> = 0 and <ub> = 200.  With such a setting <min>
             would be autoscaled, but its final value will be between 0
             and 200 (both inclusive despite the '<' sign).  If no
             lower or upper bound is specified, the '<' to also be
             ommited.  If <ub> is lower than <lb> the constraints will
             be turned off and full autoscaling will happen.  This fea-
             ture is useful to plot measured data with autoscaling but
             providing a limit on the range, to clip outliers, or to
             guarantee a minimum range that will be displayed even if
             the data would not need such a big range.

             The wwrriitteebbaacckk option essentially saves the range found by
             aauuttoossccaallee in the buffers that would be filled by sseett
             xxrraannggee.  This is useful if you wish to plot several func-
             tions together but have the range determined by only some
             of them.  The wwrriitteebbaacckk operation is performed during the
             pplloott execution, so it must be specified before that com-
             mand.  To restore, the last saved horizontal range use sseett
             xxrraannggee rreessttoorree.  For example,

                   set xrange [-10:10]
                   set yrange [] writeback
                   plot sin(x)
                   set yrange restore
                   replot x/2

             results in a yrange of [-1:1] as found only from the range
             of sin(x); the [-5:5] range of x/2 is ignored.  Executing
             sshhooww yyrraannggee after each command in the above example should
             help you understand what is going on.

             In 2D, xxrraannggee and yyrraannggee determine the extent of the axes,
             ttrraannggee determines the range of the parametric variable in
             parametric mode or the range of the angle in polar mode.
             Similarly in parametric 3D, xxrraannggee, yyrraannggee, and zzrraannggee
             govern the axes and uurraannggee and vvrraannggee govern the paramet-
             ric variables.

             In polar mode, rrrraannggee determines the radial range plotted.
             <rmin> acts as an additive constant to the radius, whereas
             <rmax> acts as a clip to the radius---no point with radius
             greater than <rmax> will be plotted.  xxrraannggee and yyrraannggee
             are affected---the ranges can be set as if the graph was
             of r(t)-rmin, with rmin added to all the labels.











   GNUPLOT 4.1                                                      243


             Any range may be partially or totally autoscaled, although
             it may not make sense to autoscale a parametric variable
             unless it is plotted with data.

             Ranges may also be specified on the pplloott command line.  A
             range given on the plot line will be used for that single
             pplloott command; a range given by a sseett command will be used
             for all subsequent plots that do not specify their own
             ranges.  The same holds true for sspplloott.

             Examples:

             To set the xrange to the default:
                   set xrange [-10:10]

             To set the yrange to increase downwards:
                   set yrange [10:-10]

             To change zmax to 10 without affecting zmin (which may
             still be autoscaled):
                   set zrange [:10]

             To autoscale xmin while leaving xmax unchanged:
                   set xrange [*:]

             To autoscale xmin but keeping xmin positive:
                   set xrange [0<*:]

             To autoscale x but keep minimum range of 10 to 50 (actual
             might be larger):
                   set xrange [*<10:50<*]

             Autoscaling but limit maximum xrange to -1000 to 1000,
             i.e. autoscaling within [-1000:1000]
                   set xrange [-1000<*:*<1000]

             Make sure xmin is somewhere between -200 and 100:
                   set xrange [-200<*<100:]




             8844..9966..  XXttiiccss


             Fine control of the major (labelled) tics on the x axis is
             possible with the sseett xxttiiccss command.  The tics may be
             turned off with the uunnsseett xxttiiccss command, and may be turned
             on (the default state) with sseett xxttiiccss.  Similar commands
             control the major tics on the y, z, x2 and y2 axes.

             Syntax:
                   set xtics {axis | border} {{no}mirror}










   GNUPLOT 4.1                                                      244


                             {in | out} {scale {default | <major>
             {,<minor>}}}
                             {{no}rotate {by <ang>}} {offset <offset> |
             nooffset}
                             {left | right | center | autojustify}
                             {add}
                             {  autofreq
                              | <incr>
                              | <start>, <incr> {,<end>}
                              | ({"<label>"} <pos> {<level>}
             {,{"<label>"}...) }
                             { format "formatstring" } { font
             "name{,<size>}" }
                             { rangelimited }
                             { textcolor <colorspec> }
                   unset xtics
                   show xtics

             The same syntax applies to yyttiiccss, zzttiiccss, xx22ttiiccss, yy22ttiiccss
             and ccbbttiiccss.

             aaxxiiss or bboorrddeerr tells ggnnuupplloott to put the tics (both the
             tics themselves and the accompanying labels) along the
             axis or the border, respectively.  If the axis is very
             close to the border, the aaxxiiss option will move the tic
             labels to outside the border.  The relevant margin set-
             tings will usually be sized badly by the automatic layout
             algorithm in this case.

             mmiirrrroorr tells ggnnuupplloott to put unlabelled tics at the same
             positions on the opposite border.  nnoommiirrrroorr does what you
             think it does.

             iinn and oouutt change the tic marks to be drawn inwards or
             outwards.

             With ssccaallee, the size of the tic marks can be adjusted. If
             <minor> is not specified, it is 0.5*<major>.  The default
             size 1.0 for major tics and 0.5 for minor tics is
             requested by ssccaallee ddeeffaauulltt.

             rroottaattee asks ggnnuupplloott to rotate the text through 90 degrees,
             which will be done if the terminal driver in use supports
             text rotation.  nnoorroottaattee cancels this. rroottaattee bbyy <<aanngg>>
             asks for rotation by <ang> degrees, supported by some ter-
             minal types.

             The defaults are bboorrddeerr mmiirrrroorr nnoorroottaattee for tics on the x
             and y axes, and bboorrddeerr nnoommiirrrroorr nnoorroottaattee for tics on the
             x2 and y2 axes.  For the z axis, the {{aaxxiiss || bboorrddeerr}}
             option is not available and the default is nnoommiirrrroorr.  If
             you do want to mirror the z-axis tics, you might want to
             create a bit more room for them with sseett bboorrddeerr.










   GNUPLOT 4.1                                                      245


             The <offset> is specified by either x,y or x,y,z, and may
             be preceded by ffiirrsstt, sseeccoonndd, ggrraapphh, ssccrreeeenn, or cchhaarraacctteerr
             to select the coordinate system. <offset> is the offset of
             the tics texts from their default positions, while the
             default coordinate system is cchhaarraacctteerr.  See ccoooorrddiinnaatteess
             for details. nnooooffffsseett switches off the offset.

             Example:

             Move xtics more closely to the plot.
                   set xtics offset 0,graph 0.05

             By default, tic labels are justified automatically depend-
             ing on the axis and rotation angle to produce aestheti-
             cally pleasing results. If this is not desired, justifica-
             tion can be overridden with an explicit lleefftt, rriigghhtt or
             cceenntteerr keyword. aauuttoojjuussttiiffyy restores the default behavior.

             sseett xxttiiccss with no options restores the default border or
             axis if xtics are being displayed;  otherwise it has no
             effect.  Any previously specified tic frequency or posi-
             tion {and labels} are retained.

             Positions of the tics are calculated automatically by
             default or if the aauuttooffrreeqq option is given; otherwise they
             may be specified in either of two forms:

             The implicit <start>, <incr>, <end> form specifies that a
             series of tics will be plotted on the axis between the
             values <start> and <end> with an increment of <incr>.  If
             <end> is not given, it is assumed to be infinity.  The
             increment may be negative.  If neither <start> nor <end>
             is given, <start> is assumed to be negative infinity,
             <end> is assumed to be positive infinity, and the tics
             will be drawn at integral multiples of <incr>.  If the
             axis is logarithmic, the increment will be used as a mul-
             tiplicative factor.

             If you specify to a negative <start> or <incr> after a
             numerical value (e.g., rroottaattee bbyy <<aannggllee>> or ooffffsseett <<ooffff--
             sseett>>), the parser fails because it subtracts <start> or
             <incr> from that value.  As a workaround, specify
             00--<<ssttaarrtt>> resp. 00--<<iinnccrr>> in that case.

             Example:
                   set xtics border offset 0,0.5 -5,1,5
             Fails with 'invalid expression' at the last comma.
                   set xtics border offset 0,0.5 0-5,1,5
             or
                   set xtics offset 0,0.5 border -5,1,5
             Sets tics at the border, tics text with an offset of 0,0.5
             characters, and sets the start, increment, and end to -5,
             1, and 5, as requested.










   GNUPLOT 4.1                                                      246


             The sseett ggrriidd options 'front', 'back' and 'layerdefault'
             affect the drawing order of the xtics, too.

             Examples:

             Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
                   set xtics 0,.5,10

             Make tics at ..., -10, -5, 0, 5, 10, ...
                   set xtics 5

             Make tics at 1, 100, 1e4, 1e6, 1e8.
                   set logscale x; set xtics 1,100,1e8

             The explicit ("<label>" <pos> <level>, ...) form allows
             arbitrary tic positions or non-numeric tic labels.  In
             this form, the tics do not need to be listed in numerical
             order.  Each tic has a position, optionally with a label.
             Note that the label is a string enclosed by quotes.  It
             may be a constant string, such as "hello", may contain
             formatting information for converting the position into
             its label, such as "%3f clients", or may be empty, "".
             See sseett ffoorrmmaatt for more information.  If no string is
             given, the default label (numerical) is used.

             An explicit tic mark has a third parameter, the "level".
             The default is level 0, a major tic.  A level of 1 gener-
             ates a minor tic.  If the level is specified, then the
             label must also be supplied.

             Examples:
                   set xtics ("low" 0, "medium" 50, "high" 100)
                   set xtics (1,2,4,8,16,32,64,128,256,512,1024)
                   set ytics ("bottom" 0, "" 10, "top" 20)
                   set ytics ("bottom" 0, "" 10 1, "top" 20)

             In the second example, all tics are labelled.  In the
             third, only the end tics are labelled.  In the fourth, the
             unlabeled tic is a minor tic.

             Normally if explicit tics are given, they are used instead
             of auto-generated tics. Conversely if you specify sseett
             xxttiiccss aauuttoo or the like it will erase any previously speci-
             fied explicit tics. You can mix explicit and auto- gener-
             ated tics by using the keyword aadddd, which must appear
             before the tic style being added.

             Example:
                   set xtics 0,.5,10
                   set xtics add ("Pi" 3.14159)

             This will automatically generate tic marks every 0.5 along
             x, but will also add an explicit labeled tic mark at pi.










   GNUPLOT 4.1                                                      247


             However they are specified, tics will only be plotted when
             in range.

             Format (or omission) of the tic labels is controlled by
             sseett ffoorrmmaatt, unless the explicit text of a label is
             included in the sseett xxttiiccss ((""<<llaabbeell>>"")) form.

             Minor (unlabelled) tics can be added automatically by the
             sseett mmxxttiiccss command, or at explicit positions by the sseett
             xxttiiccss (("""" <<ppooss>> 11,, ......)) form.




                  8844..9966..11..  XXttiiccss ttiimmee__ddaattaa


                  In case of timeseries data, axis tic position values
                  must be given as quoted dates or times according to
                  the format ttiimmeeffmmtt. If the <start>, <incr>, <end>
                  form is used, <start> and <end> must be given accord-
                  ing to ttiimmeeffmmtt, but <incr> must be in seconds.  Times
                  will be written out according to the format given on
                  sseett ffoorrmmaatt, however.

                  Examples:
                        set xdata time
                        set timefmt "%d/%m"
                        set xtics format "%b %d"
                        set xrange ["01/12":"06/12"]
                        set xtics "01/12", 172800, "05/12"

                        set xdata time
                        set timefmt "%d/%m"
                        set xtics format "%b %d"
                        set xrange ["01/12":"06/12"]
                        set xtics ("01/12", "" "03/12", "05/12")
                  Both of these will produce tics "Dec 1", "Dec 3", and
                  "Dec 5", but in the second example the tic at "Dec 3"
                  will be unlabelled.



                  8844..9966..22..  XXttiiccss rraannggeelliimmiitteedd


                  This option limits both the auto-generated axis tic
                  labels and the corresponding plot border to the range
                  of values actually present in the data that has been
                  plotted.  Note that this is independent of the cur-
                  rent range limits for the plot. For example, suppose
                  that the data in "file.dat" all lies in the range 2 <
                  y < 4.  Then the following commands will create a










   GNUPLOT 4.1                                                      248


                  plot for which the left-hand plot border (y axis) is
                  drawn for only this portion of the total y range, and
                  only the axis tics in this region are generated.
                  I.e., the plot will be scaled to the full range on y,
                  but there will be a gap between 0 and 2 on the left
                  border and another gap between 4 and 10. This style
                  is sometimes referred to as a rraannggee--ffrraammee graph.
                        set border 3
                        set yrange [0:10]
                        set ytics nomirror rangelimited
                        plot "file.dat"



             8844..9977..  XXyyppllaannee


             The sseett xxyyppllaannee command adjusts the position at which the
             xy plane is drawn in a 3D plot.  The synonym "set tic-
             slevel" is accepted for backwards compatibility.

             Syntax:
                   set xyplane at <zvalue>
                   set xyplane relative <frac>
                   set ticslevel <frac>        # equivalent to set
             xyplane relative
                   show xyplane

             The form sseett xxyyppllaannee rreellaattiivvee <<ffrraacc>> places the xy plane
             below the range in Z, where the distance from the xy plane
             to Zmin is given as a fraction of the total range in z.
             The default value is 0.5.  Negative values are permitted,
             but tic labels on the three axes may overlap.  The older,
             deprecated, form sseett ttiiccsslleevveell is retained for backwards
             compatibility.

             To place the xy-plane at a position 'pos' on the z-axis,
             ttiiccsslleevveell may be set equal to  (pos - zmin) / (zmin -
             zmax).  However, this position will change if the z range
             is changed.

             The alternative form sseett xxyyppllaannee aatt <<zzvvaalluuee>> fixes the
             placement of the xy plane at a specific Z value regardless
             of the current z range. Thus to force the x, y, and z axes
             to meet at a common origin one would specify sseett xxyyppllaannee
             aatt 00.

             See also sseett vviieeww, and sseett zzeerrooaaxxiiss.















   GNUPLOT 4.1                                                      249


             8844..9988..  XXzzeerrooaaxxiiss


             The sseett xxzzeerrooaaxxiiss command draws a line at y = 0.  For
             details, please see sseett zzeerrooaaxxiiss.



             8844..9999..  YY22ddaattaa


             The sseett yy22ddaattaa command sets y2 (right-hand) axis data to
             timeseries (dates/times).  Please see sseett xxddaattaa.



             8844..110000..  YY22ddttiiccss


             The sseett yy22ddttiiccss command changes tics on the y2 (right-
             hand) axis to days of the week.  Please see sseett xxddttiiccss for
             details.



             8844..110011..  YY22llaabbeell


             The sseett yy22llaabbeell command sets the label for the y2 (right-
             hand) axis.  Please see sseett xxllaabbeell.



             8844..110022..  YY22mmttiiccss


             The sseett yy22mmttiiccss command changes tics on the y2 (right-
             hand) axis to months of the year.  Please see sseett xxmmttiiccss
             for details.



             8844..110033..  YY22rraannggee


             The sseett yy22rraannggee command sets the vertical range that will
             be displayed on the y2 (right-hand) axis.  Please see sseett
             xxrraannggee for details.















   GNUPLOT 4.1                                                      250


             8844..110044..  YY22ttiiccss


             The sseett yy22ttiiccss command controls major (labelled) tics on
             the y2 (right-hand) axis.  Please see sseett xxttiiccss for
             details.



             8844..110055..  YY22zzeerrooaaxxiiss


             The sseett yy22zzeerrooaaxxiiss command draws a line at the origin of
             the y2 (right-hand) axis (x2 = 0).  For details, please
             see sseett zzeerrooaaxxiiss.



             8844..110066..  YYddaattaa


             The sseett yyddaattaa commands sets y-axis data to timeseries
             (dates/times).  Please see sseett xxddaattaa.



             8844..110077..  YYddttiiccss


             The sseett yyddttiiccss command changes tics on the y axis to days
             of the week.  Please see sseett xxddttiiccss for details.



             8844..110088..  YYllaabbeell


             This command sets the label for the y axis.  Please see
             sseett xxllaabbeell.



             8844..110099..  YYmmttiiccss


             The sseett yymmttiiccss command changes tics on the y axis to
             months of the year.  Please see sseett xxmmttiiccss for details.
















   GNUPLOT 4.1                                                      251


             8844..111100..  YYrraannggee


             The sseett yyrraannggee command sets the vertical range that will
             be displayed on the y axis.  Please see sseett xxrraannggee for
             details.



             8844..111111..  YYttiiccss


             The sseett yyttiiccss command controls major (labelled) tics on
             the y axis.  Please see sseett xxttiiccss for details.



             8844..111122..  YYzzeerrooaaxxiiss


             The sseett yyzzeerrooaaxxiiss command draws a line at x = 0.  For
             details, please see sseett zzeerrooaaxxiiss.



             8844..111133..  ZZddaattaa


             The sseett zzddaattaa command sets zaxis data to timeseries
             (dates/times).  Please see sseett xxddaattaa.



             8844..111144..  ZZddttiiccss


             The sseett zzddttiiccss command changes tics on the z axis to days
             of the week.  Please see sseett xxddttiiccss for details.



             8844..111155..  ZZzzeerrooaaxxiiss


             The sseett zzzzeerrooaaxxiiss command draws a line through (x=0,y=0).
             This has no effect on 2D plots, including splot with sseett
             vviieeww mmaapp. For details, please see sseett zzeerrooaaxxiiss and sseett
             xxyyppllaannee.















   GNUPLOT 4.1                                                      252


             8844..111166..  CCbbddaattaa


             Set color box axis data to timeseries (dates/times).
             Please see sseett xxddaattaa.



             8844..111177..  CCbbddttiiccss


             The sseett ccbbddttiiccss command changes tics on the color box axis
             to days of the week. Please see sseett xxddttiiccss for details.



             8844..111188..  ZZeerroo


             The zzeerroo value is the default threshold for values
             approaching 0.0.

             Syntax:
                   set zero <expression>
                   show zero

             ggnnuupplloott will not plot a point if its imaginary part is
             greater in magnitude than the zzeerroo threshold.  This
             threshold is also used in various other parts of ggnnuupplloott
             as a (crude) numerical-error threshold.  The default zzeerroo
             value is 1e-8.  zzeerroo values larger than 1e-3 (the recipro-
             cal of the number of pixels in a typical bitmap display)
             should probably be avoided, but it is not unreasonable to
             set zzeerroo to 0.0.



             8844..111199..  ZZeerrooaaxxiiss


             The x axis may be drawn by sseett xxzzeerrooaaxxiiss and removed by
             uunnsseett xxzzeerrooaaxxiiss.  Similar commands behave similarly for
             the y, x2, y2, and z axes.

             Syntax:
                   set {x|x2|y|y2|z}zeroaxis { {linestyle | ls
             <line_style>}
                                              | { linetype | lt
             <line_type>}
                                                { linewidth | lw
             <line_width>}}
                   unset {x|x2|y|y2|z}zeroaxis
                   show {x|y|z}zeroaxis










   GNUPLOT 4.1                                                      253


             By default, these options are off.  The selected zero axis
             is drawn with a line of type <line_type> and width
             <line_width> (if supported by the terminal driver cur-
             rently in use), or a user-defined style <line_style>.

             If no linetype is specified, any zero axes selected will
             be drawn using the axis linetype (linetype 0).

             sseett zzeerrooaaxxiiss is equivalent to sseett xxzzeerrooaaxxiiss;; sseett yyzzee--
             rrooaaxxiiss.  Note that the z-axis must be set separately using
             sseett zzzzeerrooaaxxiiss.

             Examples:

             To simply have the y=0 axis drawn visibly:

                    set xzeroaxis

             If you want a thick line in a different color or pattern,
             instead:

                    set xzeroaxis linetype 3 linewidth 2.5



             8844..112200..  ZZllaabbeell


             This command sets the label for the z axis.  Please see
             sseett xxllaabbeell.



             8844..112211..  ZZmmttiiccss


             The sseett zzmmttiiccss command changes tics on the z axis to
             months of the year.  Please see sseett xxmmttiiccss for details.



             8844..112222..  ZZrraannggee


             The sseett zzrraannggee command sets the range that will be dis-
             played on the z axis.  The zrange is used only by sspplloott
             and is ignored by pplloott.  Please see sseett xxrraannggee for
             details.















   GNUPLOT 4.1                                                      254


             8844..112233..  ZZttiiccss


             The sseett zzttiiccss command controls major (labelled) tics on
             the z axis.  Please see sseett xxttiiccss for details.



             8844..112244..  CCbbllaabbeell


             This command sets the label for the color box axis.
             Please see sseett xxllaabbeell.



             8844..112255..  CCbbmmttiiccss


             The sseett ccbbmmttiiccss command changes tics on the color box axis
             to months of the year. Please see sseett xxmmttiiccss for details.



             8844..112266..  CCbbrraannggee


             The sseett ccbbrraannggee command sets the range of values which are
             colored using the current ppaalleettttee by styles wwiitthh ppmm33dd,
             wwiitthh iimmaaggee and wwiitthh ppaalleettttee.  Values outside of the color
             range use color of the nearest extreme.

             If the cb-axis is autoscaled in sspplloott, then the colorbox
             range is taken from zzrraannggee.  Points drawn in sspplloott ......
             ppmm33dd||ppaalleettttee can be filtered by using different zzrraannggee and
             ccbbrraannggee.

             Please see sseett xxrraannggee for details on sseett ccbbrraannggee syntax.
             See also sseett ppaalleettttee and sseett ccoolloorrbbooxx.



             8844..112277..  CCbbttiiccss


             The sseett ccbbttiiccss command controls major (labelled) tics on
             the color box axis.  Please see sseett xxttiiccss for details.
















   GNUPLOT 4.1                                                      255


        8855..  SShheellll


        The sshheellll command spawns an interactive shell.  To return to
        ggnnuupplloott, type llooggoouutt if using VMS, eexxiitt or the END-OF-FILE
        character if using Unix, or eexxiitt if using MS-DOS or OS/2.

        There are two ways of spawning a shell command: using ssyysstteemm
        command or via !! ($ if using VMS). The former command takes a
        string as a parameter and thus it can be used anywhere among
        other gnuplot commands, while the latter syntax requires to be
        the only command on the line. Control will return immediately
        to ggnnuupplloott after this command is executed.  For example, in MS-
        DOS or OS/2,

              ! dir
        or
              system "dir"

        prints a directory listing and then returns to ggnnuupplloott.

        Other examples of the former syntax:
               system "date"; set time; plot "a.dat"
               print=1; if (print) replot; set out; system "lpr x.ps"



        8866..  SSpplloott


        sspplloott is the command for drawing 3D plots (well, actually pro-
        jections on a 2D surface, but you knew that).  It can create a
        plot from functions or data read from files in a manner very
        similar to the pplloott command.  sspplloott provides only a single x,
        y, and z axis; there is no equivalent to the x2 and y2 sec-
        ondary axes provided by pplloott.

        See the pplloott command for many options available in both 2D and
        3D plots.

        Syntax:
              splot {<ranges>}
                    {<iteration>}
                    <function> | "<datafile>" {datafile-modifiers}}
                    {<title-spec>} {with <style>}
                    {, {definitions{,}} <function> ...}

        where either a <function> or the name of a data file enclosed
        in quotes is supplied.  The function can be a mathematical
        expression, or a triple of mathematical expressions in paramet-
        ric mode.

        By default sspplloott draws the xy plane completely below the










   GNUPLOT 4.1                                                      256


        plotted data.  The offset between the lowest ztic and the xy
        plane can be changed by sseett xxyyppllaannee.  The orientation of a
        sspplloott projection is controlled by sseett vviieeww.  See sseett vviieeww and
        sseett xxyyppllaannee for more information.

        The syntax for setting ranges on the sspplloott command is the same
        as for pplloott.  In non-parametric mode, the order in which ranges
        must be given is xxrraannggee, yyrraannggee, and zzrraannggee.  In parametric
        mode, the order is uurraannggee, vvrraannggee, xxrraannggee, yyrraannggee, and zzrraannggee.

        The ttiittllee option is the same as in pplloott.  The operation of wwiitthh
        is also the same as in pplloott, except that the plotting styles
        available to sspplloott are limited to lliinneess, ppooiinnttss, lliinneessppooiinnttss,
        ddoottss, and iimmppuullsseess;  the error-bar capabilities of pplloott are not
        available for sspplloott.

        The ddaattaaffiillee options have more differences.

        See also sshhooww pplloott.




             8866..11..  DDaattaa--ffiillee


             SSpplloott, like pplloott, can display from a file.

             Syntax:
                   splot '<file_name>' {binary <binary list>}
                                       {{nonuniform} matrix}
                                       {index <index list>}
                                       {every <every list>}
                                       {using <using list>}

             The special filenames """" and ""--"" are permitted, as in
             pplloott.  See ssppeecciiaall--ffiilleennaammeess.

             In brief, bbiinnaarryy and mmaattrriixx indicate that the data are in
             a special form, iinnddeexx selects which data sets in a multi-
             data-set file are to be plotted, eevveerryy specifies which
             datalines (subsets) within a single data set are to be
             plotted, and uussiinngg determines how the columns within a
             single record are to be interpreted.

             The options iinnddeexx and eevveerryy behave the same way as with
             pplloott;  uussiinngg does so also, except that the uussiinngg list must
             provide three entries instead of two.

             The pplloott options tthhrruu and ssmmooootthh are not available for
             sspplloott, but ccnnttrrppaarraamm and ddggrriidd33dd provide limited smoothing
             capabilities.











   GNUPLOT 4.1                                                      257


             Data file organization is essentially the same as for
             pplloott, except that each point is an (x,y,z) triple.  If
             only a single value is provided, it will be used for z,
             the datablock number will be used for y, and the index of
             the data point in the datablock will be used for x.  If
             two or four values are provided, ggnnuupplloott uses the last
             value for calculating the color in pm3d plots.  Three val-
             ues are interpreted as an (x,y,z) triple.  Additional val-
             ues are generally used as errors, which can be used by
             ffiitt.

             Single blank records separate datablocks in a sspplloott
             datafile; sspplloott treats datablocks as the equivalent of
             function y-isolines.  No line will join points separated
             by a blank record.  If all datablocks contain the same
             number of points, ggnnuupplloott will draw cross-isolines between
             datablocks, connecting corresponding points.  This is
             termed "grid data", and is required for drawing a surface,
             for contouring (sseett ccoonnttoouurr) and hidden-line removal (sseett
             hhiiddddeenn33dd). See also sspplloott ggrriidd__ddaattaa.

             It is no longer necessary to specify ppaarraammeettrriicc mode for
             three-column ssppllootts.




                  8866..11..11..  MMaattrriixx


                  Gnuplot can interpret matrix input in two different
                  ways.  The first of these assumes a uniform grid of x
                  and y coordinates, and assigns each value in the
                  input matrix to one element of this uniform grid.
                  This is the default for ascii data input, but not for
                  binary input.  Example commands for plotting uniform
                  matrix data:
                       splot 'file' matrix using 1:2:3          # ascii
                  input
                       splot 'file' binary general using 1:2:3  #
                  binary input

                  In a uniform grid matrix the z-values are read in a
                  row at a time, i. e.,
                      z11 z12 z13 z14 ...
                      z21 z22 z23 z24 ...
                      z31 z32 z33 z34 ...
                  and so forth.

                  For ascii input, a blank line or comment line ends
                  the matrix, and starts a new surface mesh.  You can
                  select among the meshes inside a file by the iinnddeexx
                  option to the sspplloott command, as usual.  The second










   GNUPLOT 4.1                                                      258


                  interpretation assumes a non-uniform grid with
                  explicit x and y coordinates. The first row of input
                  data contains the y coordinates; the first column of
                  input data contains the x coordinates.  For binary
                  input data, the first element of the first row must
                  contain the number of data columns. (This number is
                  ignored for ascii input).  Both the coordinates and
                  the data values in a binary input are treated as sin-
                  gle precision floats.  Example commands for plotting
                  non-uniform matrix data:
                       splot 'file' nonuniform matrix using 1:2:3  #
                  ascii input
                       splot 'file' binary matrix using 1:2:3      #
                  binary input

                  Thus the data organization for non-uniform matrix
                  input is

                        <N+1>  <y0>   <y1>   <y2>  ...  <yN>
                         <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
                         <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
                          :      :      :      :   ...    :

                  which is then converted into triplets:
                        <x0> <y0> <z0,0>
                        <x0> <y1> <z0,1>
                        <x0> <y2> <z0,2>
                         :    :     :
                        <x0> <yN> <z0,N>

                        <x1> <y0> <z1,0>
                        <x1> <y1> <z1,1>
                         :    :     :

                  These triplets are then converted into ggnnuupplloott iso-
                  curves and then ggnnuupplloott proceeds in the usual manner
                  to do the rest of the plotting.

                  A collection of matrix and vector manipulation rou-
                  tines (in C) is provided in bbiinnaarryy..cc.  The routine to
                  write binary data is

                        int
                  fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,col-
                  umn_title)

                  An example of using these routines is provided in the
                  file bbff__tteesstt..cc, which generates binary files for the
                  demo file ddeemmoo//bbiinnaarryy..ddeemm.

                  Usage in pplloott:
                      plot `a.dat` matrix
                      plot `a.dat` matrix using 1:3










   GNUPLOT 4.1                                                      259


                      plot 'a.gpbin' {matrix} binary using 1:3
                  will plot rows of the matrix, while using 2:3 will
                  plot matrix columns, and using 1:2 the point coordi-
                  nates (rather useless). Applying the eevveerryy option you
                  can specify explicit rows and columns.

                  Example -- rescale axes of a matrix in an ascii file:
                      splot `a.dat` matrix using (1+$1):(1+$2*10):3

                  Example -- plot the 3rd row of a matrix in an ascii
                  file:
                      plot 'a.dat' matrix using 1:3 every 1:999:1:2
                  (rows are enumerated from 0, thus 2 instead of 3).

                  Gnuplot can read matrix binary files by use of the
                  option bbiinnaarryy appearing without keyword qualifica-
                  tions unique to general binary, i.e., aarrrraayy, rreeccoorrdd,
                  ffoorrmmaatt, or ffiilleettyyppee.  Other general binary keywords
                  for translation should also apply to matrix binary.
                  (See bbiinnaarryy ggeenneerraall for more details.)



                  8866..11..22..  EExxaammppllee ddaattaaffiillee


                  A simple example of plotting a 3D data file is

                        splot 'datafile.dat'

                  where the file "datafile.dat" might contain:

                        # The valley of the Gnu.
                           0 0 10
                           0 1 10
                           0 2 10

                           1 0 10
                           1 1 5
                           1 2 10

                           2 0 10
                           2 1 1
                           2 2 10

                           3 0 10
                           3 1 0
                           3 2 10

                  Note that "datafile.dat" defines a 4 by 3 grid ( 4
                  rows of 3 points each ).  Rows (datablocks) are sepa-
                  rated by blank records.











   GNUPLOT 4.1                                                      260


                  Note also that the x value is held constant within
                  each dataline.  If you instead keep y constant, and
                  plot with hidden-line removal enabled, you will find
                  that the surface is drawn 'inside-out'.

                  Actually for grid data it is not necessary to keep
                  the x values constant within a datablock, nor is it
                  necessary to keep the same sequence of y values.
                  ggnnuupplloott requires only that the number of points be
                  the same for each datablock.  However since the sur-
                  face mesh, from which contours are derived, connects
                  sequentially corresponding points, the effect of an
                  irregular grid on a surface plot is unpredictable and
                  should be examined on a case-by-case basis.



             8866..22..  GGrriidd ddaattaa


             The 3D routines are designed for points in a grid format,
             with one sample, datapoint, at each mesh intersection; the
             datapoints may originate from either evaluating a func-
             tion, see sseett iissoossaammpplleess, or reading a datafile, see sspplloott
             ddaattaaffiillee.  The term "isoline" is applied to the mesh lines
             for both functions and data.  Note that the mesh need not
             be rectangular in x and y, as it may be parameterized in u
             and v, see sseett iissoossaammpplleess.

             However, ggnnuupplloott does not require that format.  In the
             case of functions, 'samples' need not be equal to 'isosam-
             ples', i.e., not every x-isoline sample need intersect a
             y-isoline. In the case of data files, if there are an
             equal number of scattered data points in each datablock,
             then "isolines" will connect the points in a datablock,
             and "cross-isolines" will connect the corresponding points
             in each datablock to generate a "surface".  In either
             case, contour and hidden3d modes may give different plots
             than if the points were in the intended format.  Scattered
             data can be converted to a {different} grid format with
             sseett ddggrriidd33dd.

             The contour code tests for z intensity along a line
             between a point on a y-isoline and the corresponding point
             in the next y-isoline.  Thus a sspplloott contour of a surface
             with samples on the x-isolines that do not coincide with a
             y-isoline intersection will ignore such samples. Try:
                    set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
                    set style function lp
                    set contour
                    set isosamples 10,10; set samples 10,10;
                    splot cos(x)*cos(y)
                    set samples 4,10; replot










   GNUPLOT 4.1                                                      261


                    set samples 10,4; replot




             8866..33..  SSpplloott ssuurrffaacceess


             sspplloott can display a surface as a collection of points, or
             by connecting those points.  As with pplloott, the points may
             be read from a data file or result from evaluation of a
             function at specified intervals, see sseett iissoossaammpplleess.  The
             surface may be approximated by connecting the points with
             straight line segments, see sseett ssuurrffaaccee, in which case the
             surface can be made opaque with sseett hhiiddddeenn33dd..  The orien-
             tation from which the 3d surface is viewed can be changed
             with sseett vviieeww.

             Additionally, for points in a grid format, sspplloott can
             interpolate points having a common amplitude (see sseett ccoonn--
             ttoouurr) and can then connect those new points to display
             contour lines, either directly with straight-line segments
             or smoothed lines (see sseett ccnnttrrppaarraamm).  Functions are
             already evaluated in a grid format, determined by sseett
             iissoossaammpplleess and sseett ssaammpplleess, while file data must either be
             in a grid format, as described in ddaattaa--ffiillee, or be used to
             generate a grid (see sseett ddggrriidd33dd).

             Contour lines may be displayed either on the surface or
             projected onto the base.  The base projections of the con-
             tour lines may be written to a file, and then read with
             pplloott, to take advantage of pplloott's additional formatting
             capabilities.



        8877..  SSttaattss ((SSttaattiissttiiccaall SSuummmmaarryy))


        Syntax:
             stats 'filename' [using N[:M]] [name 'prefix'] [[no]out-
        put]]
        This command prepares a statistical summary of the data in one
        or two columns of a file. The using specifier is interpreted in
        the same way as for plot commands. See pplloott for details on the
        iinnddeexx, eevveerryy, and uussiinngg directives. Data points are filtered
        against both xrange and yrange before analysis. See sseett xxrraannggee.
        The summary is printed to the screen by default.  Output can be
        redirected to a file by prior use of the command sseett pprriinntt, or
        suppressed altogether using the nnoooouuttppuutt option.

        In addition to printed output, the program stores the individ-
        ual statistics into three sets of variables.  The first set of










   GNUPLOT 4.1                                                      262


        variables reports how the data is laid out in the file:
             STATS_records           # total number of in-range data
        records
             STATS_outofrange        # number of records filtered out
        by range limits
             STATS_invalid           # number of invalid/incom-
        plete/missing records
             STATS_blank             # number of blank lines in the
        file
             STATS_blocks            # number of indexable data blocks
        in the file

        The second set reports properties of the in-range data from a
        single column.  If the corresponding axis is autoscaled (x-axis
        for the 1st column, y-axis for the optional second column) then
        no range limits are applied. If two columns are being analysed
        in a single ssttaattss command, the the suffix "_x" or "_y" is
        appended to each variable name.  I.e. STATS_min_x is the mini-
        mum value found in the first column, while STATS_min_y is the
        minimum value found in the second column.
             STATS_min               # minimum value of in-range data
        points
             STATS_max               # maximum value of in-range data
        points
             STATS_index_min         # index i for which data[i] ==
        STATS_min
             STATS_index_max         # index i for which data[i] ==
        STATS_max
             STATS_lo_quartile       # value of the lower (1st) quar-
        tile boundary
             STATS_median            # median value
             STATS_up_quartile       # value of the upper (3rd) quar-
        tile boundary
             STATS_mean              # mean value of in-range data
        points
             STATS_stddev            # standard deviation of the in-
        range data points
             STATS_sum               # sum
             STATS_sumsq             # sum of squares

        The third set of variables is only relevant to analysis of two
        data columns.
             STATS_correlation       # correlation coefficient between
        x and y values
             STATS_slope             # A corresponding to a linear fit
        y = Ax + B
             STATS_intercept         # B corresponding to a linear fit
        y = Ax + B
             STATS_sumxy             # sum of x*y
             STATS_pos_min_y         # x coordinate of a point with
        minimum y value
             STATS_pos_max_y         # x coordinate of a point with
        maximum y value










   GNUPLOT 4.1                                                      263


        It may be convenient to track the statistics from more than one
        file at the same time. The nnaammee option causes the default pre-
        fix "STATS" to be replaced by a user-specified string.  For
        example, the mean value of column 2 data from two different
        files could be compared by
             stats "file1.dat" using 2 name "A"
             stats "file2.dat" using 2 name "B"
             if (A_mean < B_mean) {...}

        The index reported in STATS_index_xxx corresponds to the value
        of pseudo-column 0 ($0) in plot commands.  I.e. the first point
        has index 0, the last point has index N-1.

        Data values are sorted to find the median and quartile bound-
        aries.  If the total number of points N is odd, then the median
        value is taken as the value of data point (N+1)/2. If N is
        even, then the median is reported as the mean value of points
        N/2 and (N+2)/2. Equivalent treatment is used for the quartile
        boundaries.

        For an example of using the ssttaattss command to help annotate a
        subsequent plot, see stats.dem.

        The current implementation does not allow analysis if either
        the X or Y axis is set to log-scaling.  This restriction may be
        removed in a later version.




        8888..  SSyysstteemm


        ssyysstteemm ""ccoommmmaanndd"" executes "command" using the standard shell.
        See sshheellll.  If called as a function, ssyysstteemm((""ccoommmmaanndd"")) returns
        the resulting character stream from stdout as a string.  One
        optional trailing newline is ignored.

        This can be used to import external functions into gnuplot
        scripts:

              f(x) = real(system(sprintf("somecommand %f", x)))



        8899..  TTeesstt


        This command graphically tests or presents terminal and palette
        capabilities.

        Syntax:
              test {terminal | palette [rgb|rbg|grb|gbr|brg|bgr]}










   GNUPLOT 4.1                                                      264


        tteesstt or tteesstt tteerrmmiinnaall creates a display of line and point
        styles and other useful things appropriate for and supported by
        the tteerrmmiinnaall you are just using.

        tteesstt ppaalleettttee plots profiles of R(z),G(z),B(z), where 0<=z<=1.
        These are the RGB components of the current color ppaalleettttee. It
        also plots the apparent net intensity as calculated using NTSC
        coefficients to map RGB onto a grayscale.  The optional parame-
        ter, a permutation of letters rgb, determines the sequence in
        which the r,g,b profiles are drawn.



        9900..  UUnnddeeffiinnee


        Clear one or more previously defined user variables.  This is
        useful in order to reset the state of a script containing an
        initialization test.

        A variable name can contain the wildcard character ** as last
        character. If the wildcard character is found, all variables
        with names that begin with the prefix preceding the wildcard
        will be removed. This is useful to remove several variables
        sharing a common prefix. Note that the wildcard character is
        only allowed at the end of the variable name! Specifying the
        wildcard character as sole argument to uunnddeeffiinnee has no effect.

        Example:

              undefine foo foo1 foo2
              if (!exists("foo")) load "initialize.gp"

              bar = 1; bar1 = 2; bar2 = 3
              undefine bar*                 # removes all three vari-
        ables




        9911..  UUnnsseett


        Options set using the sseett command may be returned to their
        default state by the corresponding uunnsseett command.  The uunnsseett
        command may contain an optional iteration clause. See iitteerraa--
        ttiioonn.

        Examples:
              set xtics mirror rotate by -45 0,10,100
              ...
              unset xtics











   GNUPLOT 4.1                                                      265


              # Unset labels numbered between 100 and 200
              unset for [i=100:200] label i




             9911..11..  TTeerrmmiinnaall


             The default terminal that is active at the time of program
             entry depends on the system platform, gnuplot build
             options, and the environmental variable GNUTERM.  Whatever
             this default may be, gnuplot saves it in the internal
             variable GNUTERM.  The uunnsseett tteerrmmiinnaall command restores
             this initial state.  It is equivalent to sseett tteerrmmiinnaall
             GGNNUUTTEERRMM.



        9922..  UUppddaattee


        This command writes the current values of the fit parameters
        into the given file, formatted as an initial-value file (as
        described in the ffiittsection).  This is useful for saving the
        current values for later use or for restarting a converged or
        stopped fit.

        Syntax:
              update <filename> {<filename>}

        If a second filename is supplied, the updated values are writ-
        ten to this file, and the original parameter file is left
        unmodified.

        Otherwise, if the file already exists, ggnnuupplloott first renames it
        by appending ..oolldd and then opens a new file.  That is, "uuppddaattee
        ''ffrreedd''" behaves the same as "!!rreennaammee ffrreedd ffrreedd..oolldd;; uuppddaattee
        ''ffrreedd..oolldd'' ''ffrreedd''".  [On DOS and other systems that use the
        twelve-character "filename.ext" naming convention, "ext" will
        be "oolldd" and "filename" will be related (hopefully recogniz-
        ably) to the initial name.  Renaming is not done at all on VMS
        systems, since they use file-versioning.]

        Please see ffiitt for more information.



        9933..  WWhhiillee


        Syntax:
              while (<expr>) {










   GNUPLOT 4.1                                                      266


                  <commands>
              }
        Execute a block of commands repeatedly so long as <expr> evalu-
        ates to a non-zero value.  This command cannot be mixed with
        old-style (un-bracketed) if/else statements.  See iiff.




        9944..  TTeerrmmiinnaall ttyyppeess





        9955..  CCoommpplleettee lliisstt ooff tteerrmmiinnaallss


        Gnuplot supports a large number of output formats. These are
        selected by choosing an appropriate terminal type, possibly
        with additional modifying options. See sseett tteerrmmiinnaall.

        This document may describe terminal types that are not avail-
        able to you because they were not configured or installed on
        your system. To see a list of terminals available on a particu-
        lar gnuplot installation, type 'set terminal' with no modi-
        fiers.





             9955..11..  AAeedd776677


             The aaeedd551122 and aaeedd776677 terminal drivers support AED graph-
             ics terminals.  The two drivers differ only in their hori-
             zontal ranges, which are 512 and 768 pixels, respectively.
             Their vertical range is 575 pixels.  There are no options
             for these drivers.



             9955..22..  AAiiffmm



             NNOOTTEE:: OOuuttddaatteedd tteerrmmiinnaall, originally written for Adobe
             Illustrator 3.0+.  Since Adobe Illustrator understands
             PostScript level 1 commands directly, you should use sseett
             tteerrmmiinnaall ppoosstt lleevveell11 instead.

             Syntax:










   GNUPLOT 4.1                                                      267


                   set terminal aifm {color|monochrome} {"<fontname>"}
             {<fontsize>}




             9955..33..  AAqquuaa


             This terminal relies on AquaTerm.app for display on Mac OS
             X.

             Syntax:
                   set terminal aqua {<n>} {title "<wintitle>"} {size
             <x> <y>}
                                     {font "<fontname>{,<fontsize>}"}
                                     {{no}enhanced} {solid|dashed} {dl
             <dashlength>}}

             where <n> is the number of the window to draw in (default
             is 0), <wintitle> is the name shown in the title bar
             (default "Figure <n>"), <x> <y> is the size of the plot
             (default is 846x594 pt = 11.75x8.25 in).

             Use <fontname> to specify the font (default is "Times-
             Roman"), and <fontsize> to specify the font size (default
             is 14.0 pt).

             The aqua terminal supports enhanced text mode (see
             eennhhaanncceedd), except for overprint. Font support is limited
             to the fonts available on the system.  Character encoding
             can be selected by sseett eennccooddiinngg and currently supports
             iso_latin_1, iso_latin_2, cp1250, and UTF8 (default).

             Lines can be drawn either solid or dashed, (default is
             solid) and the dash spacing can be modified by <dash-
             length> which is a multiplier > 0.




             9955..44..  BBee


             The bbee terminal type is present if gnuplot is built for
             the bbeeooss operating system and for use with X servers.  It
             is selected at program startup if the DDIISSPPLLAAYY environment
             variable is set, if the TTEERRMM environment variable is set
             to xxtteerrmm, or if the --ddiissppllaayy command line option is used.

             Syntax:
                       set terminal be {reset} {<n>}











   GNUPLOT 4.1                                                      268


             Multiple plot windows are supported: sseett tteerrmmiinnaall bbee <<nn>>
             directs the output to plot window number n.  If n>0, the
             terminal number will be appended to the window title and
             the icon will be labeled ggpplltt <<nn>>.  The active window may
             distinguished by a change in cursor (from default to
             crosshair.)

             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing cclloossee from a window manager
             menu.  All plot windows can be closed by specifying rreesseett,
             which actually terminates the subprocess which maintains
             the windows (unless --ppeerrssiisstt was specified).

             Plot windows will automatically be closed at the end of
             the session unless the --ppeerrssiisstt option was given.

             The size or aspect ratio of a plot may be changed by
             resizing the ggnnuupplloott window.

             Linewidths and pointsizes may be changed from within ggnnuu--
             pplloott with sseett lliinneessttyyllee.

             For terminal type bbee, ggnnuupplloott accepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other ggnnuupplloott options are available for the bbee
             terminal.  These may be specified either as command-line
             options when ggnnuupplloott is invoked or as resources in the
             configuration file ".Xdefaults".  They are set upon ini-
             tialization and cannot be altered during a ggnnuupplloott ses-
             sion.




                  9955..44..11..  CCoommmmaanndd--lliinnee__ooppttiioonnss


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting ggnnuupplloott or as resources in your ".Xdefaults"
                  file:
















   GNUPLOT 4.1                                                      269


   +---------------------------------------------------------------------------------+
   |    `-mono`        forces monochrome rendering on color displays.                |
   |    `-gray`        requests grayscale rendering on grayscale or color displays.  |
   |                   (Grayscale displays receive monochrome rendering by default.) |
   |    `-clear`       requests that the window be cleared momentarily before a      |
   |                   new plot is displayed.                                        |
   |    `-raise`       raises plot window after each plot                            |
   |   `-noraise`      does not raise plot window after each plot                    |
   |   `-persist`      plots windows survive after main gnuplot program exits        |
   +---------------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.

   Example:
             gnuplot*gray: on

   ggnnuupplloott also provides a command line option (--ppooiinnttssiizzee <<vv>>) and a
   resource, ggnnuupplloott**ppooiinnttssiizzee:: <<vv>>, to control the size of points
   plotted with the ppooiinnttss plotting style.  The value vv is a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, --ppooiinnttssiizzee 22 uses points twice
   the default size, and --ppooiinnttssiizzee 00..55 uses points half the normal
   size.



                  9955..44..22..  MMoonnoocchhrroommee__ooppttiioonnss


                  For monochrome displays, ggnnuupplloott does not honor fore-
                  ground or background colors.  The default is black-
                  on-white.  --rrvv or ggnnuupplloott**rreevveerrsseeVViiddeeoo:: oonn requests
                  white-on-black.




                  9955..44..33..  CCoolloorr__rreessoouurrcceess


                  For color displays, ggnnuupplloott honors the following
                  resources (shown here with their default values) or
                  the greyscale resources.  The values may be color
                  names as listed in the BE rgb.txt file on your sys-
                  tem, hexadecimal RGB color specifications (see BE
                  documentation), or a color name followed by a comma
                  and an iinntteennssiittyy value from 0 to 1.  For example,
                  bblluuee,, 00..55 means a half intensity blue.












   GNUPLOT 4.1                                                      270


                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is, for example,

   Example:
             gnuplot -background coral




                  9955..44..44..  GGrraayyssccaallee__rreessoouurrcceess


                  When --ggrraayy is selected, ggnnuupplloott honors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.



                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+














   GNUPLOT 4.1                                                      271


                  9955..44..55..  LLiinnee__rreessoouurrcceess


                  ggnnuupplloott honors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.



                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   ggnnuupplloott honors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   jjkk (jj and kk are >= 1  and <= 9) means a dashed line with a repeated
   pattern of jj pixels on followed by kk pixels off.  For example, '16'
   is a "dotted" line with one pixel on followed by six pixels off.
   More elaborate on/off patterns can be specified with a four-digit
   value.  For example, '4441' is four on, four off, four on, one off.
   The default values shown below are for monochrome displays or mono-
   chrome rendering on color or grayscale displays.  For color dis-
   plays, the default for each is 0 (solid line) except for aaxxiissDDaasshheess
   which defaults to a '16' dotted line.



                     +------------------------------+
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+











   GNUPLOT 4.1                                                      272


             9955..55..  CCaaiirroollaatteexx


             The ccaaiirroollaatteexx terminal device generates encapsulated
             PostScript (*.eps) or PDF output using the cairo and pango
             support libraries and uses LaTeX for text output using the
             same routines as the eeppssllaatteexx terminal.

             Syntax:
                   set terminal cairolatex
                                  {eps | pdf}
                                  {standalone | input}
                                  {blacktext | colortext | colourtext}
                                  {header <header> | noheader}
                                  {mono|color} {solid|dashed}
                                  {{no}transparent} {{no}crop} {back-
             ground <rgbcolor>}
                                  {font <font>} {fontscale <scale>}
                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             The cairolatex terminal prints a plot like tteerrmmiinnaall
             eeppssccaaiirroo or tteerrmmiinnaall ppddffccaaiirroo but transfers the texts to
             LaTeX instead of including them in the graph. For refer-
             ence of options not explained here see ppddffccaaiirroo.

             eeppss and ppddff select the type of grahics output. Use eeppss
             with latex/dvips and ppddff for pdflatex.

             bbllaacckktteexxtt forces all text to be written in black even in
             color mode;

             The ccaaiirroollaatteexx driver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r,c), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.  See also the documentation for the ppssllaatteexx ter-
             minal driver.  To create multiline labels, use \short-
             stack, for example
                set ylabel '[r]{\shortstack{first line \\ second
             line}}'

             The bbaacckk option of sseett llaabbeell commands is handled slightly
             different than in other terminals. Labels using 'back' are
             printed behind all other elements of the plot while labels
             using 'front' are printed above everything else.











   GNUPLOT 4.1                                                      273


             The driver produces two different files, one for the eps
             or pdf part of the figure and one for the LaTeX part. The
             name of the LaTeX file is taken from the sseett oouuttppuutt com-
             mand. The name of the eps/pdf file is derived by replacing
             the file extension (normally '.tex') with '.eps' or '.pdf'
             instead.  There is no LaTeX output if no output file is
             given!  Remember to close the oouuttppuutt ffiillee before next plot
             unless in mmuullttiipplloott mode.

             In your LaTeX documents use '\input{filename}' to include
             the figure.  The '.eps' or '.pdf' file is included by the
             command \includegraphics{...}, so you must also include
             \usepackage{graphicx} in the LaTeX preamble.  If you want
             to use coloured text (option ccoolloouurrtteexxtt) you also have to
             include \usepackage{color} in the LaTeX preamble.

             The behaviour concerning font selection depends on the
             header mode.  In all cases, the given font size is used
             for the calculation of proper spacing. When not using the
             ssttaannddaalloonnee mode the actual LaTeX font and font size at the
             point of inclusion is taken, so use LaTeX commands for
             changing fonts. If you use e.g. 12pt as font size for your
             LaTeX document, use '", 12"' as options. The font name is
             ignored. If using ssttaannddaalloonnee the given font and font size
             are used, see below for a detailed description.

             If text is printed coloured is controlled by the TeX
             booleans \ifGPcolor and \ifGPblacktext. Only if \ifGPcolor
             is true and \ifGPblacktext is false, text is printed
             coloured. You may either change them in the generated TeX
             file or provide them globally in your TeX file, for exam-
             ple by using
                \newif\ifGPblacktext
                \GPblacktexttrue
             in the preamble of your document. The local assignment is
             only done if no global value is given.

             When using the cairolatex terminal give the name of the
             TeX file in the sseett oouuttppuutt command including the file
             extension (normally ".tex").  The graph filename is gener-
             ated by replacing the extension.

             If using the ssttaannddaalloonnee mode a complete LaTeX header is
             added to the LaTeX file; and "-inc" is added to the file-
             name of the gaph file.  The ssttaannddaalloonnee mode generates a
             TeX file that produces output with the correct size when
             using dvips, pdfTeX, or VTeX.  The default, iinnppuutt, gener-
             ates a file that has to be included into a LaTeX document
             using the \input command.

             If a font other than "" or "default" is given it is inter-
             preted as LaTeX font name.  It contains up to three parts,
             separated by a comma: 'fontname,fontseries,fontshape'.  If










   GNUPLOT 4.1                                                      274


             the default fontshape or fontseries are requested, they
             can be omitted.  Thus, the real syntax for the fontname is
             '{fontname}{,fontseries}{,fontshape}'.  The naming conven-
             tion for all parts is given by the LaTeX font scheme.  The
             fontname is 3 to 4 characters long and is built as fol-
             lows: One character for the font vendor, two characters
             for the name of the font, and optionally one additional
             character for special fonts, e.g., 'j' for fonts with old-
             style numerals or 'x' for expert fonts. The names of many
             fonts is described in
                       http://www.tug.org/fontname/fontname.pdf
             For example, 'cmr' stands for Computer Modern Roman, 'ptm'
             for Times-Roman, and 'phv' for Helvetica.  The font series
             denotes the thickness of the glyphs, in most cases 'm' for
             normal ("medium") and 'bx' or 'b' for bold fonts.  The
             font shape is 'n' for upright, 'it' for italics, 'sl' for
             slanted, or 'sc' for small caps, in general.  Some fonts
             may provide different font series or shapes.

             Examples:

             Use Times-Roman boldface (with the same shape as in the
             surrounding text):
                   set terminal cairolatex font 'ptm,bx'
             Use Helvetica, boldface, italics:
                   set terminal cairolatex font 'phv,bx,it'
             Continue to use the surrounding font in slanted shape:
                   set terminal cairolatex font ',,sl'
             Use small capitals:
                   set terminal cairolatex font ',,sc'

             By this method, only text fonts are changed. If you also
             want to change the math fonts you have to use the "gnu-
             plot.cfg" file or the hheeaaddeerr option, described below.

             In ssttaannddaalloonnee mode, the font size is taken from the given
             font size in the sseett tteerrmmiinnaall command. To be able to use a
             specified font size, a file "size<size>.clo" has to reside
             in the LaTeX search path.  By default, 10pt, 11pt, and
             12pt are supported.  If the package "extsizes" is
             installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.

             The hheeaaddeerr option takes a string as argument.  This string
             is written into the generated LaTeX file.  If using the
             ssttaannddaalloonnee mode, it is written into the preamble, directly
             before the \begin{document} command.  In the iinnppuutt mode,
             it is placed directly after the \begingroup command to
             ensure that all settings are local to the plot.

             Examples:

             Use T1 fontencoding, change the text and math font to
             Times-Roman as well as the sans-serif font to Helvetica:










   GNUPLOT 4.1                                                      275


                 set terminal cairolatex standalone header \
                 "\\usepackage[T1]{fontenc}\n\\usepackage{math-
             ptmx}\n\\usepackage{helvet}"
             Use a boldface font in the plot, not influencing the text
             outside the plot:
                 set terminal cairolatex input header "\\bfseries"

             If the file "gnuplot.cfg" is found by LaTeX it is input in
             the preamble the LaTeX document, when using ssttaannddaalloonnee
             mode.  It can be used for further settings, e.g., changing
             the document font to Times-Roman, Helvetica, and Courier,
             including math fonts (handled by "mathptmx.sty"):
                   \usepackage{mathptmx}
                   \usepackage[scaled=0.92]{helvet}
                   \usepackage{courier}
             The file "gnuplot.cfg" is loaded before the header infor-
             mation given by the hheeaaddeerr command.  Thus, you can use
             hheeaaddeerr to overwrite some of settings performed using "gnu-
             plot.cfg"




             9955..66..  CCaannvvaass



             The ccaannvvaass terminal creates a set of javascript commands
             that draw onto the HTML5 canvas element.  Syntax:
                   set terminal canvas {size <xsize>, <ysize>} {back-
             ground <rgb_color>}
                                       {font {<fontname>}{,<fontsize>}}
             | {fsize <fontsize>}
                                       {{no}enhanced} {linewidth <lw>}
                                       {rounded | butt}
                                       {solid | dashed {dashlength
             <dl>}}
                                       {standalone {mousing} | name
             '<funcname>'}
                                       {jsdir 'URL/for/javascripts'}
                                       {title '<some string>'}

             where <xsize> and <ysize> set the size of the plot area in
             pixels.  The default size in standalone mode is 600 by 400
             pixels.  The default font size is 10.

             NB: Only one font is available, the ascii portion of Her-
             shey simplex Roman provided in the file canvastext.js. You
             can replace this with the file canvasmath.js, which con-
             tains also UTF-8 encoded Hershey simplex Greek and math
             symbols. For consistency with other terminals, it is also
             possible to use ffoonntt ""nnaammee,,ssiizzee"". Currently the font nnaammee
             is ignored, but browser support for named fonts is likely










   GNUPLOT 4.1                                                      276


             to arrive eventually.

             The default ssttaannddaalloonnee mode creates an html page contain-
             ing javascript code that renders the plot using the HTML 5
             canvas element.  The html page links to two required
             javascript files 'canvastext.js' and 'gnuplot_common.js'.
             An additional file 'gnuplot_dashedlines.js' is needed to
             support dashed lines.  By default these point to local
             files, on unix-like systems usually in directory
             /usr/local/share/gnuplot/<version>/js.  See installation
             notes for other platforms. You can change this by using
             the jjssddiirr option to specify either a different local
             directory or a general URL.  The latter is usually appro-
             priate if the plot is exported for viewing on remote
             client machines.

             All plots produced by the canvas terminal are mouseable.
             The additional keyword mmoouussiinngg causes the ssttaannddaalloonnee mode
             to add a mouse-tracking box underneath the plot. It also
             adds a link to a javascript file 'gnuplot_mouse.js' and to
             a stylesheet for the mouse box 'gnuplot_mouse.css' in the
             same local or URL directory as 'canvastext.js'.

             The nnaammee option creates a file containing only javascript.
             Both the javascript function it contains and the id of the
             canvas element that it draws onto are taken from the fol-
             lowing string parameter.  The commands
                   set term canvas name 'fishplot'
                   set output 'fishplot.js'
             will create a file containing a javascript function fish-
             plot() that will draw onto a canvas with id=fishplot.  An
             html page that invokes this javascript function must also
             load the canvastext.js function as described above.  A
             minimal html file to wrap the fishplot created above might
             be:

                   <html>
                   <head>
                       <script src="canvastext.js"></script>
                       <script src="gnuplot_common.js"></script>
                   </head>
                   <body onload="fishplot();">
                       <script src="fishplot.js"></script>
                       <canvas id="fishplot" width=600 height=400>
                           <div id="err_msg">No support for HTML 5 can-
             vas element</div>
                       </canvas>
                   </body>
                   </html>

             The individual plots drawn on this canvas will have names
             fishplot_plot_1, fishplot_plot_2, and so on. These can be
             referenced by external javascript routines, for example










   GNUPLOT 4.1                                                      277


             gnuplot.toggle_visibility("fishplot_plot_2").




             9955..77..  CCggii


             The ccggii and hhccggii terminal drivers support SCO CGI drivers.
             hhccggii is for printers; the environment variable CGIPRNT
             must be set.  ccggii may be used for either a display or
             hardcopy; the environment variable CGIDISP is checked,
             first, then CGIPRNT.  These terminals have no options.



             9955..88..  CCggmm


             The ccggmm terminal generates a Computer Graphics Metafile,
             Version 1.  This file format is a subset of the ANSI
             X3.122-1986 standard entitled "Computer Graphics -
             Metafile for the Storage and Transfer of Picture Descrip-
             tion Information".

             Syntax:
                   set terminal cgm {color | monochrome} {solid |
             dashed} {{no}rotate}
                                    {<mode>} {width <plot_width>}
             {linewidth <line_width>}
                                    {font "<fontname>,<fontsize>"}
                                    {background <rgb_color>}
               [deprecated]         {<color0> <color1> <color2> ...}

             ssoolliidd draws all curves with solid lines, overriding any
             dashed patterns; <mode> is llaannddssccaappee, ppoorrttrraaiitt, or
             ddeeffaauulltt; <plot_width> is the assumed width of the plot in
             points; <line_width> is the line width in points (default
             1); <fontname> is the name of a font (see list of fonts
             below) <fontsize> is the size of the font in points
             (default 12).

             The first six options can be in any order.  Selecting
             ddeeffaauulltt sets all options to their default values.

             The mechanism of setting line colors in the sseett tteerrmm com-
             mand is deprecated.  Instead you should set the background
             using a separate keyword and set the line colors using sseett
             lliinneettyyppee.  The deprecated mechanism accepted colors of the
             form 'xrrggbb', where x is the literal character 'x' and
             'rrggbb' are the red, green and blue components in hex.
             The first color was used for the background, subsequent
             colors are assigned to successive line types.










   GNUPLOT 4.1                                                      278


             Examples:
                   set terminal cgm landscape color rotate dashed width
             432 \
                                  linewidth 1  'Helvetica Bold' 12
             # defaults
                   set terminal cgm linewidth 2  14  # wider lines &
             larger font
                   set terminal cgm portrait "Times Italic" 12
                   set terminal cgm color solid      # no pesky dashes!




                  9955..88..11..  CCggmm ffoonntt


                  The first part of a Computer Graphics Metafile, the
                  metafile description, includes a font table.  In the
                  picture body, a font is designated by an index into
                  this table.  By default, this terminal generates a
                  table with the following 35 fonts, plus six more with
                  iittaalliicc replaced by oobblliiqquuee, or vice-versa (since at
                  least the Microsoft Office and Corel Draw CGM import
                  filters treat iittaalliicc and oobblliiqquuee as equivalent):







































   GNUPLOT 4.1                                                      279


                   +-----------------------------------+
                   |        CGM fonts                  |
                   +-----------------------------------+
                   |        Helvetica                  |
                   |        Helvetica Bold             |
                   |        Helvetica Oblique          |
                   |        Helvetica Bold Oblique     |
                   |        Times Roman                |
                   |        Times Bold                 |
                   |        Times Italic               |
                   |        Times Bold Italic          |
                   |        Courier                    |
                   |        Courier Bold               |
                   |        Courier Oblique            |
                   |        Courier Bold Oblique       |
                   |        Symbol                     |
                   |        Hershey/Cartographic_Roman |
                   |        Hershey/Cartographic_Greek |
                   |        Hershey/Simplex_Roman      |
                   |        Hershey/Simplex_Greek      |
                   |        Hershey/Simplex_Script     |
                   |        Hershey/Complex_Roman      |
                   |        Hershey/Complex_Greek      |
                   |        Hershey/Complex_Script     |
                   |        Hershey/Complex_Italic     |
                   |        Hershey/Complex_Cyrillic   |
                   |        Hershey/Duplex_Roman       |
                   |        Hershey/Triplex_Roman      |
                   |        Hershey/Triplex_Italic     |
                   |        Hershey/Gothic_German      |
                   |        Hershey/Gothic_English     |
                   |        Hershey/Gothic_Italian     |
                   |        Hershey/Symbol_Set_1       |
                   |        Hershey/Symbol_Set_2       |
                   |        Hershey/Symbol_Math        |
                   |        ZapfDingbats               |
                   |        Script                     |
                   |        15                         |
                   +-----------------------------------+


   The first thirteen of these fonts are required for WebCGM.  The
   Microsoft Office CGM import filter implements the 13 standard fonts
   listed above, and also 'ZapfDingbats' and 'Script'.  However, the
   script font may only be accessed under the name '15'.  For more on
   Microsoft import filter font substitutions, check its help file
   which you may find here:
     C:\Program Files\Microsoft Office\Office\Cgmimp32.hlp
   and/or its configuration file, which you may find here:
     C:\Program Files\Common Files\Microsoft
   Shared\Grphflt\Cgmimp32.cfg

   In the sseett tteerrmm command, you may specify a font name which does not










   GNUPLOT 4.1                                                      280


   appear in the default font table.  In that case, a new font table is
   constructed with the specified font as its first entry. You must
   ensure that the spelling, capitalization, and spacing of the name
   are appropriate for the application that will read the CGM file.
   (Gnuplot and any MIL-D-28003A compliant application ignore case in
   font names.)  If you need to add several new fonts, use several sseett
   tteerrmm commands.

   Example:
         set terminal cgm 'Old English'
         set terminal cgm 'Tengwar'
         set terminal cgm 'Arabic'
         set output 'myfile.cgm'
         plot ...
         set output

   You cannot introduce a new font in a sseett llaabbeell command.



                  9955..88..22..  CCggmm ffoonnttssiizzee


                  Fonts are scaled assuming the page is 6 inches wide.
                  If the ssiizzee command is used to change the aspect
                  ratio of the page or the CGM file is converted to a
                  different width, the resulting font sizes will be
                  scaled up or down accordingly.  To change the assumed
                  width, use the wwiiddtthh option.



                  9955..88..33..  CCggmm lliinneewwiiddtthh


                  The lliinneewwiiddtthh option sets the width of lines in pt.
                  The default width is 1 pt.  Scaling is affected by
                  the actual width of the page, as discussed under the
                  ffoonnttssiizzee and wwiiddtthh options.



                  9955..88..44..  CCggmm rroottaattee


                  The nnoorroottaattee option may be used to disable text rota-
                  tion.  For example, the CGM input filter for Word for
                  Windows 6.0c can accept rotated text, but the DRAW
                  editor within Word cannot.  If you edit a graph (for
                  example, to label a curve), all rotated text is
                  restored to horizontal.  The Y axis label will then
                  extend beyond the clip boundary.  With nnoorroottaattee, the
                  Y axis label starts in a less attractive location,










   GNUPLOT 4.1                                                      281


                  but the page can be edited without damage.  The
                  rroottaattee option confirms the default behavior.



                  9955..88..55..  CCggmm ssoolliidd


                  The ssoolliidd option may be used to disable dashed line
                  styles in the plots.  This is useful when color is
                  enabled and the dashing of the lines detracts from
                  the appearance of the plot. The ddaasshheedd option con-
                  firms the default behavior, which gives a different
                  dash pattern to each line type.



                  9955..88..66..  CCggmm ssiizzee


                  Default size of a CGM plot is 32599 units wide and
                  23457 units high for landscape, or 23457 units wide
                  by 32599 units high for portrait.



                  9955..88..77..  CCggmm wwiiddtthh


                  All distances in the CGM file are in abstract units.
                  The application that reads the file determines the
                  size of the final plot.  By default, the width of the
                  final plot is assumed to be 6 inches (15.24 cm).
                  This distance is used to calculate the correct font
                  size, and may be changed with the wwiiddtthh option.  The
                  keyword should be followed by the width in points.
                  (Here, a point is 1/72 inch, as in PostScript.  This
                  unit is known as a "big point" in TeX.)  Gnuplot
                  eexxpprreessssiioonnss can be used to convert from other units.

                  Example:
                        set terminal cgm width 432            # default
                        set terminal cgm width 6*72           # same as
                  above
                        set terminal cgm width 10/2.54*72     # 10 cm
                  wide



                  9955..88..88..  CCggmm nnooffoonnttlliisstt













   GNUPLOT 4.1                                                      282


                  The default font table includes the fonts recommended
                  for WebCGM, which are compatible with the Computer
                  Graphics Metafile input filter for Microsoft Office
                  and Corel Draw.  Another application might use dif-
                  ferent fonts and/or different font names, which may
                  not be documented.  The nnooffoonnttlliisstt (synonym wwiinnwwoorrdd66)
                  option deletes the font table from the CGM file.  In
                  this case, the reading application should use a
                  default table.  Gnuplot will still use its own
                  default font table to select font indices.  Thus,
                  'Helvetica' will give you an index of 1, which should
                  get you the first entry in your application's default
                  font table. 'Helvetica Bold' will give you its second
                  entry, etc.




             9955..99..  CCoonntteexxtt


             ConTeXt is a macro package for TeX, highly integrated with
             Metapost (for drawing figures) and intended for creation
             of high-quality PDF documents.  The terminal outputs Meta-
             fun source, which can be edited manually, but you should
             be able to configure most things from outside.

             For an average user of ConTeXt + gnuplot module it's rec-
             ommended to refer to UUssiinngg CCoonnTTeeXXtt rather than reading
             this page or to read the manual of the gnuplot module for
             ConTeXt.

             The ccoonntteexxtt terminal supports the following options:

             Syntax:
                  set term context {default}
                          {defaultsize | size <scale> | size
             <xsize>{in|cm}, <ysize>{in|cm}}
                          {input | standalone}
                          {timestamp | notimestamp}
                          {noheader | header "<header>"}
                          {color | colour | monochrome}
                          {rounded | mitered | beveled} {round | butt |
             squared}
                          {dashed | solid} {dashlength | dl <dl>}
                          {linewidth | lw <lw>}
                          {fontscale <fontscale>}
                          {mppoints | texpoints}
                          {inlineimages | externalimages}
                          {defaultfont | font "{<fontname>}{,<font-
             size>}"}

             In non-standalone (iinnppuutt) graphic only parameters ssiizzee to










   GNUPLOT 4.1                                                      283


             select graphic size, ffoonnttssccaallee to scale all the labels for
             a factor <fontscale> and font size, make sense, the rest
             is silently ignored and should be configured in the .tex
             file which inputs the graphic.  It's highly recommended to
             set the proper fontsize if document font differs from
             12pt, so that gnuplot will know how much space to reserve
             for labels.

             ddeeffaauulltt resets all the options to their default values.

             ddeeffaauullttssiizzee sets the plot size to 5in,3in.  ssiizzee <scale>
             sets the plot size to <scale> times <default value>.  If
             two arguments are given (separated with ','), the first
             one sets the horizontal size and the second one the verti-
             cal size.  Size may be given without units (in which case
             it means relative to the default value), with inches
             ('in') or centimeters ('cm').

             iinnppuutt (default) creates a graphic that can be included
             into another ConTeXt document.  ssttaannddaalloonnee adds some
             lines, so that the document might be compiled as-is.  You
             might also want to add hheeaaddeerr in that case.

             Use hheeaaddeerr for any additional settings/definitions/macros
             that you might want to include in a standalone graphic.
             nnoohheeaaddeerr is the default.

             nnoottiimmeessttaammpp prevents printing creation time in comments
             (if version control is used, one may prefer not to commit
             new version when only date changes).

             ccoolloorr to make color plots is the default, but mmoonnoocchhrroommee
             doesn't do anything special yet.  If you have any good
             ideas how the behaviour should differ to suit the mono-
             chrome printers better, your suggestions are welcome.

             rroouunnddeedd (default), mmiitteerreedd and bbeevveelleedd control the shape
             of line joins.  rroouunndd (default), bbuutttt and ssqquuaarreedd control
             the shape of line caps.  See PostScript or PDF Reference
             Manual for explanation. For wild-behaving functions and
             thick lines it is better to use rroouunnddeedd and rroouunndd to pre-
             vent sharp corners in line joins.  (Some general support
             for this should be added to Gnuplot, so that the same
             options could be set for each line (style) separately).

             ddaasshheedd (default) uses different dash patterns for differ-
             ent line types, ssoolliidd draws all plots with solid lines.

             ddaasshhlleennggtthh or ddll scales the length of the dashed-line seg-
             ments by <dl>.  lliinneewwiiddtthh or llww scales all linewidths by
             <lw>.  (lw 1 stands for 0.5bp, which is the default line
             width when drawing with Metapost.)  ffoonnttssccaallee scales text
             labels for factor <fontscale> relative to default document










   GNUPLOT 4.1                                                      284


             font.

             mmppppooiinnttss uses predefined point shapes, drawn in Metapost.
             tteexxppooiinnttss uses easily configurable set of symbols, defined
             with ConTeXt in the following way:
                  \defineconversion[my own points][+,{\ss x},\mathemat-
             ics{\circ}]
                  \setupGNUPLOTterminal[context][points=tex,pointset=my
             own points]

             iinnlliinneeiimmaaggeess writes binary images to a string and only
             works in ConTeXt MKIV.  eexxtteerrnnaalliimmaaggeess writes PNG files to
             disk and also works with ConTeXt MKII.  Gnuplot needs to
             have support for PNG images built in for this to work.

             With ffoonntt you can set font name and size in standalone
             graphics.  In non-standalone (iinnppuutt) mode only the font
             size is important to reserve enough space for text labels.
             The command
                  set term context font "myfont,ss,10"
             will result in
                  \setupbodyfont[myfont,ss,10pt]
             If you additionaly set ffoonnttssccaallee to 0.8 for example, then
             the resulting font will be 8pt big and
                  set label ... font "myfont,12"
             will come out as 9.6pt.

             It is your own responsibility to provide proper type-
             scripts (and header), otherwise switching the font will
             have no effect.  For a standard font in ConTeXt MKII (pdf-
             TeX) you could use:
                  set terminal context standalone header '\usetype-
             script[iwona][ec]' \
                      font "iwona,ss,11"
             Please take a look into ConTeXt documentation, wiki or
             mailing list (archives) for any up-to-date information
             about font usage.

             Examples:
                  set terminal context size 10cm, 5cm     # 10cm, 5cm
                  set terminal context size 4in, 3in      # 4in, 3in
             For standalone (whole-page) plots with labels in UTF-8
             encoding:
                  set terminal context standalone header
             '\enableregime[utf-8]'


















   GNUPLOT 4.1                                                      285


                  9955..99..11..  RReeqquuiirreemmeennttss


                  You need gnuplot module for ConTeXt
                       http://ctan.org/pkg/context-gnuplot
                  and a recent version of ConTeXt.  If you want to call
                  gnuplot on-the-fly, you also need write18 enabled.
                  In most TeX distributions this can be set with
                  shell_escape=t in texmf.cnf.

                  See
                            http://wiki.contextgarden.net/Gnuplot
                  for details about this terminal and for more exhaus-
                  tive help & examples.




                  9955..99..22..  CCaalllliinngg ggnnuupplloott ffrroomm CCoonnTTeeXXtt


                  The easiest way to make plots in ConTeXt documents is
                       \usemodule[gnuplot]
                       \starttext
                       \title{How to draw nice plots with {\sc gnu-
                  plot}?}
                       \startGNUPLOTscript[sin]
                       set format y "%.1f"
                       plot sin(x) t '$\sin(x)$'
                       \stopGNUPLOTscript
                       \useGNUPLOTgraphic[sin]
                       \stoptext
                  This will run gnuplot automatically and include the
                  resulting figure in the document.



             9955..1100..  CCoorreell


             The ccoorreell terminal driver supports CorelDraw.

             Syntax:
                   set terminal corel {  default
                                       | {monochrome | color
                                            {"<font>" {<fontsize>
                                               {<xsize> <ysize>
             {<linewidth> }}}}}

             where the fontsize and linewidth are specified in points
             and the sizes in inches.  The defaults are monochrome,
             "SwitzerlandLight", 22, 8.2, 10 and 1.2.











   GNUPLOT 4.1                                                      286


             9955..1111..  DDeebbuugg


             This terminal is provided to allow for the debugging of
             ggnnuupplloott.  It is likely to be of use only for users who are
             modifying the source code.



             9955..1122..  DDuummbb


             The dduummbb terminal driver plots into a text block using
             ascii characters.  It has an optional size specification
             and a trailing linefeed flag.

             Syntax:
                   set terminal dumb {size <xchars>,<ychars>}
             {[no]feed}
                                     {[no]enhanced}

             where <xchars> and <ychars> set the size of the text
             block. The default is 79 by 24. The last newline is
             printed only if ffeeeedd is enabled.

             Example:
                   set term dumb size 60,15
                   plot [-5:6.5] sin(x) with impulse

                        1
             +-------------------------------------------------+
                      0.8 +|||++                   ++||||++   sin(x)
             +----+ |
                      0.6 +|||||+                 ++|||||||+
             |
                      0.4 +||||||+               ++|||||||||+
             |
                      0.2 +|||||||+             ++|||||||||||+
             +|
                        0
             ++++++++++++++++++++++++++++++++++++++++++++++++++|
                     -0.2 +        +|||||||||||+
             +|||||||||||+ |
                     -0.4 +         +|||||||||+
             +|||||||||+  |
                     -0.6 +          +|||||||+
             +|||||||+   |
                     -0.8 +   +       ++||||+   +       +
             ++||||+  + |
                       -1
             +---+--------+--------+-------+--------+--------+-+
                             -4       -2        0       2        4
             6










   GNUPLOT 4.1                                                      287


             9955..1133..  DDxxff


             The ddxxff terminal driver creates pictures that can be
             imported into AutoCad (Release 10.x).  It has no options
             of its own, but some features of its plots may be modified
             by other means.  The default size is 120x80 AutoCad units,
             which can be changed by sseett ssiizzee.  ddxxff uses seven colors
             (white, red, yellow, green, cyan, blue and magenta), which
             can be changed only by modifying the source file.  If a
             black-and-white plotting device is used, the colors are
             mapped to differing line thicknesses.  See the description
             of the AutoCad print/plot command.



             9955..1144..  DDxxyy880000aa


             This terminal driver supports the Roland DXY800A plotter.
             It has no options.



             9955..1155..  EEeeppiicc


             The eeeeppiicc terminal driver supports the extended LaTeX pic-
             ture environment.  It is an alternative to the llaatteexx
             driver.

             The output of this terminal is intended for use with the
             "eepic.sty" macro package for LaTeX.  To use it, you need
             "eepic.sty", "epic.sty" and a printer driver that supports
             the "tpic" \specials.  If your printer driver doesn't sup-
             port those \specials, "eepicemu.sty" will enable you to
             use some of them.  dvips and dvipdfm do support the "tpic"
             \specials.

             Syntax:
                set terminal eepic {default} {color|dashed} {rotate}
             {size XX,YY}
                                   {small|tiny|<fontsize>}

             Options: You can give options in any order you wish.
             'color' causes gnuplot to produce \color{...} commands so
             that the graphs are colored. Using this option, you must
             include \usepackage{color} in the preambel of your latex
             document.  'dashed' will allow dashed line types; without
             this option, only solid lines with varying thickness will
             be used.  'dashed' and 'color' are mutually exclusive; if
             'color' is specified, then 'dashed' will be ignored.
             'rotate' will enable true rotated text (by 90 degrees).










   GNUPLOT 4.1                                                      288


             Otherwise, rotated text will be typeset with letters
             stacked above each other. If you use this option you must
             include \usepackage{graphicx} in the preamble.  'small'
             will use \scriptsize symbols as point markers (Probably
             does not work with TeX, only LaTeX2e). Default is to use
             the default math size.  'tiny' uses \scriptscriptstyle
             symbols.  'default' resets all options to their defaults =
             no color, no dashed lines, pseudo-rotated (stacked) text,
             large point symbols.  <fontsize> is a number which speci-
             fies the font size inside the picture environment; the
             unit is pt (points), i.e., 10 pt equals approx. 3.5 mm.
             If fontsize is not specified, then all text inside the
             picture will be set in \footnotesize.

             Notes: Remember to escape the # character (or other chars
             meaningful to (La-)TeX) by \\ (2 backslashes).  It seems
             that dashed lines become solid lines when the vertices of
             a plot are too close. (I do not know if that is a general
             problem with the tpic specials, or if it is caused by a
             bug in eepic.sty or dvips/dvipdfm.)  The default size of
             an eepic plot is 5x3 inches. You can change this using the
             ssiizzee terminal option.  Points, among other things, are
             drawn using the LaTeX commands "\Diamond", "\Box", etc.
             These commands no longer belong to the LaTeX2e core; they
             are included in the latexsym package, which is part of the
             base distribution and thus part of any LaTeX implementa-
             tion. Please do not forget to use this package.  Instead
             of latexsym, you can also include the amssymb package.
             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to
             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Examples: set term eepic
               output graphs as eepic macros inside a picture environ-
             ment;
               \input the resulting file in your LaTeX document.
             set term eepic color tiny rotate 8
               eepic macros with \color macros, \scripscriptsize point
             markers,
               true rotated text, and all text set with 8pt.

             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):










   GNUPLOT 4.1                                                      289


                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             9955..1166..  EEmmff


             The eemmff terminal generates an Enhanced Metafile Format
             file.  This file format is recognized by many Windows
             applications.

             Syntax:
                   set terminal emf {color | monochrome} {solid |
             dashed}
                                    {enhanced {noproportional}}
                                    {rounded | butt}
                                    {linewidth <LW>} {dashlength <DL>}
                                    {size XX,YY} {background
             <rgb_color>}
                                    {font "<fontname>{,<fontsize>}"}
                                    {fontscale <scale>}

             In mmoonnoocchhrroommee mode successive line types cycle through
             dash patterns.  In ccoolloorr mode successive line types use
             successive colors, and only after all 8 default colors are
             exhausted is the dash pattern incremented.  ssoolliidd draws
             all curves with solid lines, overriding any dashed pat-
             terns; lliinneewwiiddtthh <<ffaaccttoorr>> multiplies all line widths by
             this factor.  ddaasshhlleennggtthh <<ffaaccttoorr>> is useful for thick
             lines.  <fontname> is the name of a font; and <<ffoonnttssiizzee>>
             is the size of the font in points.

             The nominal size of the output image defaults to 1024x768
             in arbitrary units. You may specify a different nominal
             size using the ssiizzee option.

             Enhanced text mode tries to approximate proportional char-
             acter spacing.  If you are using a monospaced font, or
             don't like the approximation, you can turn off this cor-
             rection using the nnoopprrooppoorrttiioonnaall option.

             The default settings are ccoolloorr ssoolliidd ffoonntt ""AArriiaall,,1122"" ssiizzee
             11002244,,776688 Selecting ddeeffaauulltt sets all options to their
             default values.

             Examples:
                   set terminal emf 'Times Roman Italic, 12'
                   set terminal emf dashed    # otherwise all lines are
             solid











   GNUPLOT 4.1                                                      290


             9955..1177..  EEmmxxvvggaa


             The eemmxxvvggaa, eemmxxvveessaa and vvggaall terminal drivers support PCs
             with SVGA, vesa SVGA and VGA graphics boards, respec-
             tively.  They are intended to be compiled with "emx-gcc"
             under either DOS or OS/2.  They also need VESA and SVGAKIT
             maintained by Johannes Martin (JMARTIN@GOOFY.ZDV.UNI-
             MAINZ.DE) with additions by David J. Liu
             (liu@phri.nyu.edu).

             Syntax:
                   set terminal emxvga
                   set terminal emxvesa {vesa-mode}
                   set terminal vgal

             The only option is the vesa mode for eemmxxvveessaa, which
             defaults to G640x480x256.



             9955..1188..  EEppssccaaiirroo


             The eeppssccaaiirroo terminal device generates encapsulated Post-
             Script (*.eps) using the cairo and pango support
             libraries.  cairo verion >= 1.6 is required.

             Please read the help for the ppddffccaaiirroo terminal.



             9955..1199..  EEppssllaatteexx


             The eeppssllaatteexx driver generates output for further process-
             ing by LaTeX.

             Syntax:
                   set terminal epslatex   {default}
                   set terminal epslatex   {standalone | input}
                                           {oldstyle | newstyle}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}
                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam










   GNUPLOT 4.1                                                      291


             <samples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {header <header> | noheader}
                                           {blacktext | colortext |
             colourtext}
                                           {{font} "fontname{,font-
             size}" {<fontsize>}}
                                           {fontscale <scale>}

             The epslatex terminal prints a plot as tteerrmmiinnaall ppoossttssccrriipptt
             eeppss but transfers the texts to LaTeX instead of including
             in the PostScript code. Thus, many options are the same as
             in the ppoossttssccrriipptt tteerrmmiinnaall.

             The appearance of the epslatex terminal changed between
             versions 4.0 and 4.2 to reach better consistency with the
             postscript terminal: The plot size has been changed from 5
             x 3 inches to 5 x 3.5 inches; the character width is now
             estimated to be 60% of the font size while the old epsla-
             tex terminal used 50%;  now, the larger number of post-
             script linetypes and symbols are used.  To reach an
             appearance that is nearly identical to the old one specify
             the option oollddssttyyllee. (In fact some small differences
             remain: the symbol sizes are slightly different, the tics
             are half as large as in the old terminal which can be
             changed using sseett ttiiccss ssccaallee, and the arrows have all fea-
             tures as in the postscript terminal.)

             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in ppoossttssccrriipptt pprroo--
             lloogguuee.

             The option ccoolloorr enables color, while mmoonnoocchhrroommee prefers
             black and white drawing elements. Further, mmoonnoocchhrroommee uses
             gray ppaalleettttee but it does not change color of objects spec-
             ified with an explicit ccoolloorrssppeecc.  ssoolliidd draws all plots
             with solid lines, overriding any dashed patterns.  ddaasshh--
             lleennggtthh or ddll scales the length of the dashed-line segments
             by <DL>, which is a floating-point number greater than
             zero.  lliinneewwiiddtthh or llww scales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The lleevveell11 option sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag lleevveell11 can be toggled later by










   GNUPLOT 4.1                                                      292


             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.

             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.

             cclliipp tells PostScript to clip all output to the bounding
             box; nnoocclliipp is the default.

             ppaallffuunnccppaarraamm controls how sseett ppaalleettttee ffuunnccttiioonnss are
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via sseett ppaalleettttee ffuunnccttiioonnss) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             ssiizzee option changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the ssiizzee option.  NB: tthhiiss iiss aa cchhaannggee ffrroomm tthhee pprreevvii--
             oouussllyy rreeccoommmmeennddeedd mmeetthhoodd ooff uussiinngg tthhee sseett ssiizzee ccoommmmaanndd
             pprriioorr ttoo sseettttiinngg tthhee tteerrmmiinnaall ttyyppee.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             bbllaacckktteexxtt forces all text to be written in black even in
             color mode;

             The epslatex driver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r,c), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.  See also the documentation for the ppssllaatteexx ter-
             minal driver.  To create multiline labels, use \short-
             stack, for example










   GNUPLOT 4.1                                                      293


                set ylabel '[r]{\shortstack{first line \\ second
             line}}'

             The bbaacckk option of sseett llaabbeell commands is handled slightly
             different than in other terminals. Labels using 'back' are
             printed behind all other elements of the plot while labels
             using 'front' are printed above everything else.

             The driver produces two different files, one for the eps
             part of the figure and one for the LaTeX part. The name of
             the LaTeX file is taken from the sseett oouuttppuutt command. The
             name of the eps file is derived by replacing the file
             extension (normally ..tteexx) with ..eeppss instead.  There is no
             LaTeX output if no output file is given!  Remember to
             close the oouuttppuutt ffiillee before next plot unless in mmuullttiipplloott
             mode.

             In your LaTeX documents use '\input{filename}' to include
             the figure.  The ..eeppss file is included by the command
             \includegraphics{...}, so you must also include \usepack-
             age{graphicx} in the LaTeX preamble.  If you want to use
             coloured text (option tteexxttccoolloouurr) you also have to include
             \usepackage{color} in the LaTeX preamble.

             Pdf files can be made from the eps file using 'epstopdf'.
             If the graphics package is properly configured, the LaTeX
             files can also be processed by pdflatex without changes,
             using the pdf files instead of the eps files.  The behav-
             iour concerning font selection depends on the header mode.
             In all cases, the given font size is used for the calcula-
             tion of proper spacing. When not using the ssttaannddaalloonnee mode
             the actual LaTeX font and font size at the point of inclu-
             sion is taken, so use LaTeX commands for changing fonts.
             If you use e.g. 12pt as font size for your LaTeX document,
             use '"" 12' as options. The font name is ignored. If using
             ssttaannddaalloonnee the given font and font size are used, see
             below for a detailed description.

             If text is printed coloured is controlled by the TeX
             booleans \ifGPcolor and \ifGPblacktext. Only if \ifGPcolor
             is true and \ifGPblacktext is false, text is printed
             coloured. You may either change them in the generated TeX
             file or provide them globally in your TeX file, for exam-
             ple by using
                \newif\ifGPblacktext
                \GPblacktexttrue
             in the preamble of your document. The local assignment is
             only done if no global value is given.

             When using the epslatex terminal give the name of the TeX
             file in the sseett oouuttppuutt command including the file exten-
             sion (normally ".tex").  The eps filename is generated by
             replacing the extension by ".eps".










   GNUPLOT 4.1                                                      294


             If using the ssttaannddaalloonnee mode a complete LaTeX header is
             added to the LaTeX file; and "-inc" is added to the file-
             name of the eps file.  The ssttaannddaalloonnee mode generates a TeX
             file that produces output with the correct size when using
             dvips, pdfTeX, or VTeX.  The default, iinnppuutt, generates a
             file that has to be included into a LaTeX document using
             the \input command.

             If a font other than "" or "default" is given it is inter-
             preted as LaTeX font name.  It contains up to three parts,
             separated by a comma: 'fontname,fontseries,fontshape'.  If
             the default fontshape or fontseries are requested, they
             can be omitted.  Thus, the real syntax for the fontname is
             '[fontname][,fontseries][,fontshape]'.  The naming conven-
             tion for all parts is given by the LaTeX font scheme.  The
             fontname is 3 to 4 characters long and is built as fol-
             lows: One character for the font vendor, two characters
             for the name of the font, and optionally one additional
             character for special fonts, e.g., 'j' for fonts with old-
             style numerals or 'x' for expert fonts. The names of many
             fonts is described in
                       http://www.tug.org/fontname/fontname.pdf
             For example, 'cmr' stands for Computer Modern Roman, 'ptm'
             for Times-Roman, and 'phv' for Helvetica.  The font series
             denotes the thickness of the glyphs, in most cases 'm' for
             normal ("medium") and 'bx' or 'b' for bold fonts.  The
             font shape is 'n' for upright, 'it' for italics, 'sl' for
             slanted, or 'sc' for small caps, in general.  Some fonts
             may provide different font series or shapes.

             Examples:

             Use Times-Roman boldface (with the same shape as in the
             surrounding text):
                   set terminal epslatex 'ptm,bx'
             Use Helvetica, boldface, italics:
                   set terminal epslatex 'phv,bx,it'
             Continue to use the surrounding font in slanted shape:
                   set terminal epslatex ',,sl'
             Use small capitals:
                   set terminal epslatex ',,sc'

             By this method, only text fonts are changed. If you also
             want to change the math fonts you have to use the "gnu-
             plot.cfg" file or the hheeaaddeerr option, described below.

             In standalone mode, the font size is taken from the given
             font size in the sseett tteerrmmiinnaall command. To be able to use a
             specified font size, a file "size<size>.clo" has to reside
             in the LaTeX search path.  By default, 10pt, 11pt, and
             12pt are supported.  If the package "extsizes" is
             installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.











   GNUPLOT 4.1                                                      295


             The hheeaaddeerr option takes a string as argument.  This string
             is written into the generated LaTeX file.  If using the
             ssttaannddaalloonnee mode, it is written into the preamble, directly
             before the \begin{document} command.  In the iinnppuutt mode,
             it is placed directly after the \begingroup command to
             ensure that all settings are local to the plot.

             Examples:

             Use T1 fontencoding, change the text and math font to
             Times-Roman as well as the sans-serif font to Helvetica:
                 set terminal epslatex standalone header \
                 "\\usepackage[T1]{fontenc}\n\\usepackage{math-
             ptmx}\n\\usepackage{helvet}"
             Use a boldface font in the plot, not influencing the text
             outside the plot:
                 set terminal epslatex input header "\\bfseries"

             If the file "gnuplot.cfg" is found by LaTeX it is input in
             the preamble the LaTeX document, when using ssttaannddaalloonnee
             mode.  It can be used for further settings, e.g., changing
             the document font to Times-Roman, Helvetica, and Courier,
             including math fonts (handled by "mathptmx.sty"):
                   \usepackage{mathptmx}
                   \usepackage[scaled=0.92]{helvet}
                   \usepackage{courier}
             The file "gnuplot.cfg" is loaded before the header infor-
             mation given by the hheeaaddeerr command.  Thus, you can use
             hheeaaddeerr to overwrite some of settings performed using "gnu-
             plot.cfg"




             9955..2200..  EEppssoonn__118800ddppii


             This driver supports a family of Epson printers and deriv-
             atives.

             eeppssoonn__118800ddppii and eeppssoonn__6600ddppii are drivers for Epson LQ-
             style 24-pin printers with resolutions of 180 and 60 dots
             per inch, respectively.

             eeppssoonn__llxx880000 is a generic 9-pin driver appropriate for
             printers like the Epson LX-800, the Star NL-10 and
             NX-1000, the PROPRINTER, and so forth.

             nneecc__ccpp66 is generic 24-pin driver that can be used for
             printers like the NEC CP6 and the Epson LQ-800.

             The ookkiiddaattaa driver supports the 9-pin OKIDATA 320/321
             Standard printers.










   GNUPLOT 4.1                                                      296


             The ssttaarrcc driver is for the Star Color Printer.

             The ttaannddyy__6600ddppii driver is for the Tandy DMP-130 series of
             9-pin, 60-dpi printers.

             The ddppuu441144 driver is for the Seiko DPU-414 thermal
             printer.

             nneecc__ccpp66 has the options:

             Syntax:
                   set terminal nec_cp6 {monochrome | colour | draft}

             which defaults to monochrome.

             ddppuu441144 has the options:

             Syntax:
                   set terminal dpu414 {small | medium | large} {normal
             | draft}

             which defaults to medium (=font size) and normal.  Pre-
             ferred combinations are mmeeddiiuumm nnoorrmmaall and ssmmaallll ddrraafftt.




             9955..2211..  EExxccll


             The eexxccll terminal driver supports Talaris printers such as
             the EXCL Laser printer and the 1590.  It has no options.



             9955..2222..  FFiigg


             The ffiigg terminal device generates output in the Fig graph-
             ics language.

             Syntax:
                   set terminal fig {monochrome | color}
                                    {landscape | portrait}
                                    {small | big | size <xsize>
             <ysize>}
                                    {metric | inches}
                                    {pointsmax <max_points>}
                                    {solid | dashed}
                                    {font "<fontname>{,<fontsize>}"}
                                    {textnormal | {textspecial texthid-
             den textrigid}}
                                    {{thickness|linewidth} <units>}










   GNUPLOT 4.1                                                      297


                                    {depth <layer>}
                                    {version <number>}

             mmoonnoocchhrroommee and ccoolloorr determine whether the picture is
             black-and-white or ccoolloorr.  ssmmaallll and bbiigg produce a 5x3 or
             8x5 inch graph in the default llaannddssccaappee mode and 3x5 or
             5x8 inches in ppoorrttrraaiitt mode.  ssiizzee sets (overrides) the
             size of the drawing area to <xsize>*<ysize> in units of
             inches or centimeters depending on the iinncchheess or mmeettrriicc
             setting in effect.  The latter settings is also used as
             default units for editing with "xfig".

             ppooiinnttssmmaaxx <<mmaaxx__ppooiinnttss>> sets the maximum number of points
             per polyline.

             ssoolliidd inhibits automatic usage of ddaasshhed lines when solid
             linestyles are used up, which otherwise occurs.

             ffoonntt sets the text font face to <fontname> and its size to
             <fontsize> points. tteexxttnnoorrmmaall resets the text flags and
             selects postscript fonts, tteexxttssppeecciiaall sets the text flags
             for LaTeX specials, tteexxtthhiiddddeenn sets the hidden flag and
             tteexxttrriiggiidd the rigid flag.

             ddeepptthh sets the default depth layer for all lines and text.
             The default depth is 10 to leave room for adding material
             with "xfig" on top of the plot.

             vveerrssiioonn sets the format version of the generated fig out-
             put. Currently only versions 3.1 and 3.2 are supported.

             tthhiicckknneessss sets the default line thickness, which is 1 if
             not specified.  Overriding the thickness can be achieved
             by adding a multiple of 100 to the lliinneettyyppee value for a
             pplloott command.  In a similar way the ddeepptthh of plot elements
             (with respect to the default depth) can be controlled by
             adding a multiple of 1000 to <linetype>.  The depth is
             then <layer> + <linetype>/1000 and the thickness is
             (<linetype>%1000)/100 or, if that is zero, the default
             line thickness. lliinneewwiiddtthh is a synonym for tthhiicckknneessss.

             Additional point-plot symbols are also available with the
             ffiigg driver. The symbols can be used through ppooiinnttttyyppee val-
             ues % 100 above 50, with different fill intensities con-
             trolled by <pointtype> % 5 and outlines in black (for
             <pointtype> % 10 < 5) or in the current color.  Available
             symbols are
                     50 - 59:  circles
                     60 - 69:  squares
                     70 - 79:  diamonds
                     80 - 89:  upwards triangles
                     90 - 99:  downwards triangles
             The size of these symbols is linked to the font size.  The










   GNUPLOT 4.1                                                      298


             depth of symbols is by default one less than the depth for
             lines to achieve nice error bars.  If <pointtype> is above
             1000, the depth is <layer> + <pointtype>/1000-1.  If
             <pointtype>%1000 is above 100, the fill color is (<point-
             type>%1000)/100-1.

             Available fill colors are (from 1 to 9): black, blue,
             green, cyan, red, magenta, yellow, white and dark blue (in
             monochrome mode: black for 1 to 6 and white for 7 to 9).

             See pplloott wwiitthh for details of <linetype> and <pointtype>.

             The bbiigg option is a substitute for the bbffiigg terminal in
             earlier versions, which is no longer supported.

             Examples:
                   set terminal fig monochrome small pointsmax 1000  #
             defaults

                   plot 'file.dat' with points linetype 102 pointtype
             759
             would produce circles with a blue outline of width 1 and
             yellow fill color.

                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 554
             would produce errorbars with black lines and circles
             filled red.  These circles are one layer above the lines
             (at depth 9 by default).

             To plot the error bars on top of the circles use
                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 2554



             9955..2233..  GGggii


             The ggggii driver can run on different targets as X or
             svgalib.

             Syntax:
                set terminal ggi [acceleration <integer>] [[mode]
             {mode}]

             In X the window cannot be resized using window manager
             handles, but the mode can be given with the mode option,
             e.g.:
              - V1024x768
              - V800x600
              - V640x480
              - V320x200










   GNUPLOT 4.1                                                      299


             Please refer to the ggi documentation for other modes. The
             'mode' keyword is optional. It is recommended to select
             the target by environment variables as explained in the
             libggi manual page. To get DGA on X, you should for exam-
             ple
                bash> export GGI_DISPLAY=DGA
                csh>  setenv GGI_DISPLAY DGA

             'acceleration' is only used for targets which report rela-
             tive pointer motion events (e.g. DGA) and is a strictly
             positive integer multiplication factor for the relative
             distances.  The default for acceleration is 7.

             Examples:
                set term ggi acc 10
                set term ggi acc 1 mode V1024x768
                set term ggi V1024x768



             9955..2244..  GGiiff


             Syntax:
                   set terminal gif
                          {{no}enhanced}
                          {{no}transparent} {rounded|butt}
                          {linewidth <lw>} {dashlength <dl>}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {animate {delay <d>} {loop <n>} {{no}opti-
             mize}}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  GIF plots may be viewed interactively by
             piping the output to the 'display' program from the
             ImageMagick package as follows:
                            set term gif
                            set output '| display gif:-'
             You can view the output from successive plot commands
             interactively by typing <space> in the display window.  To
             save the current plot to a file, left click in the display
             window and choose ssaavvee.

             ttrraannssppaarreenntt instructs the driver to make the background
             color transparent.  Default is nnoottrraannssppaarreenntt.

             The lliinneewwiiddtthh and ddaasshhlleennggtthh options are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.










   GNUPLOT 4.1                                                      300


             bbuutttt instructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is rroouunnddeedd.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term gif font arial 11
                  set term gif font "arial,11"
             For more information please see the separate section under
             ffoonnttss.

             The aanniimmaattee option is available only if your local gd
             library supports the creation of animated gifs. The
             default delay between display of successive images may be
             specified in units of 1/100 second (default 5).  The
             actual delay may vary depending on the program used as a
             viewer.  Number of animation loops can be specified,
             default 0 means infinity.  An animation sequence is termi-
             nated by the next sseett oouuttppuutt or sseett tteerrmm command.  The
             ooppttiimmiizzee option has two effects on the animation.

             1) A single color map is used for the entire animation.
             This requires that all colors used in any frame of the
             animation are already defined in the first frame.

             2) If possible, only the portions of a frame that differ
             from the previous frame are stored in the animation file.
             This space saving may not be possible if the animation
             uses transparency.

             Both of these optimizations are intended to produce a
             smaller output file, but the decrease in size is probably
             only significant for long animations or very small frame
             sizes.  The nnooooppttiimmiizzee option turns off both of the
             effects just described.  Each frame is stored in its
             entirety along with a private color map.  Note that it is
             possible to post-process a non-optimized animation using
             external utilities, and this post-processing can yield a
             smaller file than gnuplot's internal optimization mode.
             The default is nnooooppttiimmiizzee.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under ccaannvvaass and sseett ssiizzee.  Blank space at the edges of
             the finished plot may be trimmed using the ccrroopp option,
             resulting in a smaller final image size. Default is
             nnooccrroopp.














   GNUPLOT 4.1                                                      301


                  9955..2244..11..  EExxaammpplleess


                        set terminal gif medium size 640,480 background
                  '#ffffff'

                  Use the medium size built-in non-scaleable, non-
                  rotatable font.  Use white (24 bit RGB in hexadeci-
                  mal) for the non-transparent background.

                        set terminal gif font arial 14 enhanced

                  Searches for a scalable font with face name 'arial'
                  and sets the font size to 14pt.  Please see ffoonnttss for
                  details of how the font search is done.  Because this
                  is a scalable font, we can use enhanced text mode.

                        set term gif animate transparent opt delay 10
                  size 200,200
                        load "animate2.dem"

                  Open the gif terminal for creation of an animated gif
                  file.  The individual frames of the animation
                  sequence are created by the script file animate2.dem
                  from the standard collection of demos.




             9955..2255..  GGppiicc


             The ggppiicc terminal driver generates GPIC graphs in the Free
             Software Foundations's "groff" package.  The default size
             is 5 x 3 inches.  The only option is the origin, which
             defaults to (0,0).

             Syntax:
                   set terminal gpic {<x> <y>}

             where xx and yy are in inches.

             A simple graph can be formatted using

                   groff -p -mpic -Tps file.pic > file.ps.

             The output from pic can be pipe-lined into eqn, so it is
             possible to put complex functions in a graph with the sseett
             llaabbeell and sseett {{xx//yy}}llaabbeell commands.  For instance,

                   set ylab '@space 0 int from 0 to x alpha ( t ) roman
             d t@'











   GNUPLOT 4.1                                                      302


             will label the y axis with a nice integral if formatted
             with the command:

                   gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-
             package] -Tps
                       > filename.ps

             Figures made this way can be scaled to fit into a docu-
             ment.  The pic language is easy to understand, so the
             graphs can be edited by hand if need be.  All co-ordinates
             in the pic-file produced by ggnnuupplloott are given as x+gnu-
             plotx and y+gnuploty.  By default x and y are given the
             value 0.  If this line is removed with an editor in a num-
             ber of files, one can put several graphs in one figure
             like this (default size is 5.0x3.0 inches):

                   .PS 8.0
                   x=0;y=3
                   copy "figa.pic"
                   x=5;y=3
                   copy "figb.pic"
                   x=0;y=0
                   copy "figc.pic"
                   x=5;y=0
                   copy "figd.pic"
                   .PE

             This will produce an 8-inch-wide figure with four graphs
             in two rows on top of each other.

             One can also achieve the same thing by the command

                   set terminal gpic x y

             for example, using

                   .PS 6.0
                   copy "trig.pic"
                   .PE



             9955..2266..  GGrraassss


             The ggrraassss terminal driver gives ggnnuupplloott capabilities to
             users of the GRASS geographic information system.  Contact
             grassp-list@moon.cecer.army.mil for more information.
             Pages are written to the current frame of the GRASS Graph-
             ics Window.  There are no options.













   GNUPLOT 4.1                                                      303


             9955..2277..  HHpp22662233aa


             The hhpp22662233aa terminal driver supports the Hewlett Packard
             HP2623A.  It has no options.



             9955..2288..  HHpp22664488


             The hhpp22664488 terminal driver supports the Hewlett Packard
             HP2647 and HP2648.  It has no options.



             9955..2299..  HHpp550000cc


             The hhpp550000cc terminal driver supports the Hewlett Packard HP
             DeskJet 500c.  It has options for resolution and compres-
             sion.

             Syntax:
                   set terminal hp500c {<res>} {<comp>}

             where rreess can be 75, 100, 150 or 300 dots per inch and
             ccoommpp can be "rle", or "tiff".  Any other inputs are
             replaced by the defaults, which are 75 dpi and no compres-
             sion.  Rasterization at the higher resolutions may require
             a large amount of memory.



             9955..3300..  HHppggll


             The hhppggll driver produces HPGL output for devices like the
             HP7475A plotter.  There are two options which can be set:
             the number of pens and eejjeecctt, which tells the plotter to
             eject a page when done.  The default is to use 6 pens and
             not to eject the page when done.

             The international character sets ISO-8859-1 and CP850 are
             recognized via sseett eennccooddiinngg iissoo__88885599__11 or sseett eennccooddiinngg
             ccpp885500 (see sseett eennccooddiinngg for details).

             Syntax:
                   set terminal hpgl {<number_of_pens>} {eject}

             The selection

                   set terminal hpgl 8 eject










   GNUPLOT 4.1                                                      304


             is equivalent to the previous hhpp77555500 terminal, and the
             selection

                   set terminal hpgl 4

             is equivalent to the previous hhpp77558800bb terminal.

             The ppccll55 driver supports plotters such as the Hewlett-
             Packard Designjet 750C, the Hewlett-Packard Laserjet III,
             and the Hewlett-Packard Laserjet IV.  It actually uses
             HPGL-2, but there is a name conflict among the terminal
             devices.  It has several options which must be specified
             in the order indicated below:

             Syntax:
                   set terminal pcl5 {mode <mode>} {<plotsize>}
                       {{color {<number_of_pens>}} | monochrome} {solid
             | dashed}
                       {font <font>} {size <fontsize>} {pspoints | nop-
             spoints}

             <mode> is llaannddssccaappee or ppoorrttrraaiitt. <plotsize> is the physi-
             cal plotting size of the plot, which is one of the follow-
             ing: lleetttteerr for standard (8 1/2" X 11") displays, lleeggaall
             for (8 1/2" X 14") displays, nnooeexxtteennddeedd for (36" X 48")
             displays (a letter size ratio) or, eexxtteennddeedd for (36" X
             55") displays (almost a legal size ratio).  ccoolloorr is for
             multi-pen (i.e. color) plots, and <number_of_pens> is the
             number of pens (i.e. colors) used in color plots. mmoonnoo--
             cchhrroommee is for one (e.g. black) pen plots. ssoolliidd draws all
             lines as solid lines, or ddaasshheedd will draw lines with dif-
             ferent dashed and dotted line patterns.  <font> is ssttiicckk,
             uunniivveerrss, ccgg__ttiimmeess, zzaappff__ddiinnggbbaattss, aannttiiqquuee__oolliivvee, aarriiaall,
             ccoouurriieerr, ggaarraammoonndd__aannttiigguuaa, lleetttteerr__ggootthhiicc, ccgg__oommeeggaa, aallbbeerr--
             ttuuss, ttiimmeess__nneeww__rroommaann, ccllaarreennddoonn, ccoorroonneett, mmaarriiggoolldd, ttrruuee--
             ttyyppee__ssyymmbboollss, or wwiinnggddiinnggss. <fontsize> is the font size in
             points.  The point type selection can be the standard
             default set by specifying nnooppssppooiinnttss, or the same set of
             point types found in the postscript terminal by specifying
             ppssppooiinnttss.

             Note that built-in support of some of these options is
             printer device dependent. For instance, all the fonts are
             supposedly supported by the HP Laserjet IV, but only a few
             (e.g. univers, stick) may be supported by the HP Laserjet
             III and the Designjet 750C. Also, color obviously won't
             work on the the laserjets since they are monochrome
             devices.

             Defaults: landscape, noextended, color (6 pens), solid,
             univers, 12 point,
                       and nopspoints.











   GNUPLOT 4.1                                                      305


             With ppccll55 international characters are handled by the
             printer; you just put the appropriate 8-bit character
             codes into the text strings.  You don't need to bother
             with sseett eennccooddiinngg.

             HPGL graphics can be imported by many software packages.



             9955..3311..  HHpplljjiiii


             The hhpplljjiiii terminal driver supports the HP Laserjet Series
             II printer.  The hhppddjj driver supports the HP DeskJet 500
             printer.  These drivers allow a choice of resolutions.

             Syntax:
                   set terminal hpljii | hpdj {<res>}

             where rreess may be 75, 100, 150 or 300 dots per inch; the
             default is 75.  Rasterization at the higher resolutions
             may require a large amount of memory.

             The hhpp550000cc terminal is similar to hhppddjj; hhpp550000cc addition-
             ally supports color and compression.



             9955..3322..  HHppppjj


             The hhppppjj terminal driver supports the HP PaintJet and
             HP3630 printers.  The only option is the choice of font.

             Syntax:
                   set terminal hppj {FNT5X9 | FNT9X17 | FNT13X25}

             with the middle-sized font (FNT9X17) being the default.



             9955..3333..  IImmaaggeenn


             The iimmaaggeenn terminal driver supports Imagen laser printers.
             It is capable of placing multiple graphs on a single page.

             Syntax:
                   set terminal imagen {<fontsize>} {portrait | land-
             scape}
                                       {[<horiz>,<vert>]}

             where ffoonnttssiizzee defaults to 12 points and the layout










   GNUPLOT 4.1                                                      306


             defaults to llaannddssccaappee.  <<hhoorriizz>> and <<vveerrtt>> are the number
             of graphs in the horizontal and vertical directions; these
             default to unity.

             Example:
                   set terminal imagen portrait [2,3]

             puts six graphs on the page in three rows of two in por-
             trait orientation.



             9955..3344..  JJppeegg


             Syntax:
                   set terminal jpeg
                          {{no}enhanced}
                          {{no}interlace}
                          {linewidth <lw>} {dashlength <dl>}
             {rounded|butt}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  In most cases, PNG is to be preferred for
             single plots, and GIF for animations.  Both are loss-less
             image formats, and produce better image quality than the
             lossy JPEG format. This is in particular noticeable for
             solid color lines against a solid background, i.e. exactly
             the sort of image typically created by gnuplot.

             The iinntteerrllaaccee option creates a progressive JPEG image.
             Default is nnooiinntteerrllaaccee.

             The lliinneewwiiddtthh and ddaasshhlleennggtthh options are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.

             bbuutttt instructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is rroouunnddeedd.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term jpeg font arial 11
                  set term jpeg font "arial,11"
             For more information please see the separate section under










   GNUPLOT 4.1                                                      307


             ffoonnttss.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under ccaannvvaass and sseett ssiizzee.  Blank space at the edges of
             the finished plot may be trimmed using the ccrroopp option,
             resulting in a smaller final image size. Default is
             nnooccrroopp.




             9955..3355..  KKyyoo


             The kkyyoo and pprreessccrriibbee terminal drivers support the Kyocera
             laser printer.  The only difference between the two is
             that kkyyoo uses "Helvetica" whereas pprreessccrriibbee uses
             "Courier".  There are no options.



             9955..3366..  LLaatteexx


             Syntax:
                   set terminal {latex | emtex} {default |
             {courier|roman} {<fontsize>}}
                                {size <XX>{unit}, <YY>{unit}} {rotate |
             norotate}

             By default the plot will inherit font settings from the
             embedding document.  You have the option of forcing either
             Courier (cmtt) or Roman (cmr) fonts instead. In this case
             you may also specify a fontsize.  Unless your driver is
             capable of building fonts at any size (e.g. dvips), stick
             to the standard 10, 11 and 12 point sizes.

             METAFONT users beware: METAFONT does not like odd sizes.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to
             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the










   GNUPLOT 4.1                                                      308


             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.  Other point types use symbols
             from the amssymb package.

             The default size for the plot is 5 inches by 3 inches. The
             ssiizzee option changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possible (currently only cm).

             If 'rotate' is specified, rotated text, especially a
             rotated y-axis label, is possible (the packages graphics
             or graphicx are needed). The 'stacked' y-axis label mecha-
             nism is then deactivated.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             9955..3377..  LLiinnuuxx


             The lliinnuuxx driver has no additional options to specify.  It
             looks at the environment variable GSVGAMODE for the
             default mode; if not set, it uses 1024x768x256 as default
             mode or, if that is not possible, 640x480x16 (standard
             VGA).



             9955..3388..  LLuuaa


             The lluuaa generic terminal driver works in conjunction with
             an external Lua script to create a target-specific plot
             file.  Currently the only supported target is TikZ ->
             pdflatex.

             Information about Lua is available at http://www.lua.org .

             Syntax:
                set terminal lua <target name> | "<file name>"
                                    {<script_args> ...}
                                    {help}










   GNUPLOT 4.1                                                      309


             A 'target name' or 'file name' (in quotes) for a script is
             mandatory.  If a 'target name' for the script is given,
             the terminal will look for "gnuplot-<target name>.lua" in
             the local directory and on failure in the environmental
             variable GNUPLOT_LUA_DIR.

             All arguments will be provided to the selected script for
             further evaluation. E.g. 'set term lua tikz help' will
             cause the script itself to print additional help on
             options and choices for the script.




                  9955..3388..11..  LLuuaa ttiikkzz


                  The TikZ driver is one output mode of the generic Lua
                  terminal.

                  Syntax:
                      set terminal lua tikz

                       {latex | tex | context}
                       {color | monochrome}
                       {dashed | solid}
                       {nooriginreset | originreset}
                       {nogparrows | gparrows}
                       {nogppoints | gppoints}
                       {picenvironment | nopicenvironment}
                       {noclip | clip}
                       {notightboundingbox | tightboundingbox}
                       {background "<colorpec>"}
                       {size <x>{unit},<y>{unit}}
                       {scale <x>,<y>}
                       {plotsize <x>{unit},<y>{unit}}
                       {charsize <x>{unit},<y>{unit}}
                       {font "<fontdesc>"}
                       {{fontscale | textscale} <scale>}
                       {nofulldoc | nostandalone | fulldoc | stand-
                  alone}
                       {{preamble | header} "<preamble_string>"}
                       {tikzplot <ltn>,...}
                       {notikzarrows | tikzarrows}
                       {rgbimages | cmykimages}
                       {noexternalimages|externalimages}
                       {bitmap | nobitmap}
                       {providevars <var name>,...}
                       {createstyle}
                       {help}

                  For all options that expect lengths as their argu-
                  ments they will default to 'cm' if no unit is










   GNUPLOT 4.1                                                      310


                  specified. For all lengths the following units may be
                  used: 'cm', 'mm', 'in' or 'inch', 'pt', 'pc', 'bp',
                  'dd', 'cc'. Blanks between numbers and units are not
                  allowed.

                  'monochrome' disables line coloring and switches to
                  grayscaled fills.

                  'solid' use only solid lines.

                  'originreset' moves the origin of the TikZ picture to
                  the lower left corner of the plot. It may be used to
                  align several plots within one tikzpicture environ-
                  ment. This is not tested with multiplots and pm3d
                  plots!

                  'gparrows' use gnuplot's internal arrow drawing func-
                  tion instead of the ones provided by TikZ.

                  'gppoints' use gnuplot's internal plotmark drawing
                  function instead of the ones provided by TikZ.

                  'nopicenvironment' omits the declaration of the
                  'tikzpicture' environment in order to set it manu-
                  ally. This permits putting some PGF/TikZ code
                  directly before or after the plot.

                  'clip' crops the plot at the defined canvas size.
                  Default is 'noclip' by which only a minimum bounding
                  box of the canvas size is set. Neither a fixed bound-
                  ing box nor a crop box is set if the 'plotsize' or
                  'tightboundingbox' option is used.

                  If 'tightboundingbox' is set the 'clip' option is
                  ignored and the final bounding box is the natural
                  bounding box calculated by tikz.

                  'background' sets the background color to the value
                  specified in the <colorpec> argument. <colorspec>
                  must be a valid color name or a 3 byte RGB code as a
                  hexadecimal number with a preceding number sign
                  ('#'). E.g. '#ff0000' specifies pure red. If omitted
                  the background is transparent.

                  The 'size' option expects two lenghts <x> and <y> as
                  the canvas size. The default size of the canvas is
                  12.5cm x 8.75cm.

                  The 'scale' option works similar to the 'size' option
                  but expects scaling factors <x> and <y> instead of
                  lengths.

                  The 'plotsize' option permits setting the size of the










   GNUPLOT 4.1                                                      311


                  plot area instead of the canvas size, which is the
                  usual gnuplot behaviour.  Using this option may lead
                  to slightly asymmetric tic lengths.  Like 'originre-
                  set' this option may not lead to convenient results
                  if used with multiplots or pm3d plots. An alternative
                  approach is to set all margins to zero and to use the
                  'noclip' option.  The plot area has then the dimen-
                  sions of the given canvas sizes.

                  The 'charsize' option expects the average horizontal
                  and vertical size of the used font. Look at the gen-
                  erated style file for an example of how to use it
                  from within your TeX document.

                  'fontscale' or 'textscale' expects a scaling factor
                  as a parameter.  All texts in the plot are scaled by
                  this factor then.

                  The options 'tex', 'latex' and 'context' choose the
                  TeX output format. LaTeX is the default. To load the
                  style file put the according line at the beginning of
                  your document:
                    \input gnuplot-lua-tikz.tex    % (for plain TeX)
                    \usepackage{gnuplot-lua-tikz}  % (for LaTeX)
                    \usemodule[gnuplot-lua-tikz]   % (for ConTeXt)

                  'createstyle' derives the TeX/LaTeX/ConTeXt styles
                  from the script and writes them to the appropriate
                  files.

                  'fulldoc' or 'standalone' produces a full LaTeX docu-
                  ment for direct compilation.

                  'preamble' or 'header' may be used to put any addi-
                  tional LaTeX code into the document preamble in
                  standalone mode.

                  With the 'tikzplot' option the '\path plot' command
                  will be used instead of only '\path'. The following
                  list of numbers of linetypes (<ltn>,...) defines the
                  affected plotlines. There exists a plotstyle for
                  every linetype. The default plotstyle is 'smooth' for
                  every linetype >= 1.

                  By using the 'tikzarrows' option the gnuplot arrow
                  styles defined by the user will be mapped to TikZ
                  arrow styles. This is done by 'misusing' the angle
                  value of the arrow definition. E.g. an arrow style
                  with the angle '7' will be mapped to the TikZ style
                  'gp arrow 7' ignoring all the other given values. By
                  default the TikZ terminal uses the stealth' arrow
                  tips for all arrows. To obtain the default gnuplot
                  behaviour please use the 'gparrows' option.










   GNUPLOT 4.1                                                      312


                  With 'cmykimages' the CMYK color model will be used
                  for inline image data instead of the RGB model. All
                  other colors (like line colors etc.) are not affected
                  by this option, since they are handled e.g. by
                  LaTeX's xcolor package. This option is ignored if
                  images are externalized.

                  By using the 'externalimages' option all bitmap
                  images will be written as external PNG images and
                  included at compile time of the document.  Generating
                  DVI and later postscript files requires to convert
                  the PNGs into EPS files in a seperate step e.g. by
                  using ImageMagick's ccoonnvveerrtt.  Transparent bitmap
                  images are always generated as an external PNGs.

                  The 'nobitmap' option let images be rendered as
                  filled rectangles instead of the nativ PS or PDF
                  inline image format. This option is ignored if images
                  are externalized.

                  The 'providevars' options makes gnuplot's internal
                  and user variables available by using the '\gpget-
                  var{<var name>}' commmand within the TeX script. Use
                  gnuplot's 'show variables all' command to see the
                  list of valid variables.

                  The <fontdesc> string may contain any valid
                  TeX/LaTeX/ConTeXt font commands like e.g. '\small'.
                  It is passed directly as a node parameter in form of
                  "font={<fontdesc>}". This can be 'misused' to add
                  further code to a node, e.g. '\small,yshift=1ex' or
                  ',yshift=1ex' are also valid while the latter does
                  not change the current font settings. One exception
                  is the second argument of the list. If it is a number
                  of the form <number>{unit} it will be interpreted as
                  a fontsize like in other terminals and will be
                  appended to the first argument. If the unit is omit-
                  ted the value is interpreted as 'pt'. As an example
                  the string '\sffamily,12,fill=red' sets the font to
                  LaTeX's sans serif font at a size of 12pt and red
                  background color.  The same applies to ConTeXt, e.g.
                  '\switchtobodyfont[iwona],10' changes the font to
                  Iwona at a size of 10pt.  Plain TeX users have to
                  change the font size explicitly within the first
                  argument. The second should be set to the same value
                  to get proper scaling of text boxes.

                  Strings have to be put in single or double quotes.
                  Double quoted strings may contain special characters
                  like newlines '\n' etc.













   GNUPLOT 4.1                                                      313


             9955..3399..  MMaacciinnttoosshh


             Syntax:
                  set terminal macintosh {singlewin | multiwin} {verti-
             cal | novertical}
                                         {size <width>, <height> |
             default}

             'singlewin' limits the output to a single window and is
             useful for animations.  'multiwin' allows multiple win-
             dows.  'vertical' is only valid under the gx option. With
             this option, rotated text will be drawn vertically. nover-
             tical turns this option off.  size <width>, <height> over-
             rides the graph size set in the preferences dialog until
             it is cleared with either 'set term mac size default' or
             'set term mac default'.

             'set term mac size default' sets the window size settings
             to those set in the preferences dialog.

             'set term mac default' sets all options to their default
             values.  Default values: nogx, multiwin, novertical.

             If you generate graphs under the multiwin option and then
             switch to singlewin, the next plot command will cause one
             more window to be created. This new window will be reused
             as long as singlewin is in effect. If you switch back to
             multiwin, generate some graphs, and then switch to sin-
             glewin again, the orginal 'singlewin' window will be
             resused if it is still open. Otherwise a new 'singlewin'
             window will be created. The 'singlewin' window is not num-
             bered.



             9955..4400..  MMff


             The mmff terminal driver creates an input file to the META-
             FONT program.  Thus a figure may be used in the TeX docu-
             ment in the same way as is a character.

             To use a picture in a document, the METAFONT program must
             be run with the output file from ggnnuupplloott as input.  Thus,
             the user needs a basic knowledge of the font creating
             process and the procedure for including a new font in a
             document.  However, if the METAFONT program is set up
             properly at the local site, an unexperienced user could
             perform the operation without much trouble.

             The text support is based on a METAFONT character set.
             Currently the Computer Modern Roman font set is input, but










   GNUPLOT 4.1                                                      314


             the user is in principal free to choose whatever fonts he
             or she needs.  The METAFONT source files for the chosen
             font must be available.  Each character is stored in a
             separate picture variable in METAFONT.  These variables
             may be manipulated (rotated, scaled etc.) when characters
             are needed.  The drawback is the interpretation time in
             the METAFONT program.  On some machines (i.e. PC) the lim-
             ited amount of memory available may also cause problems if
             too many pictures are stored.

             The mmff terminal has no options.




                  9955..4400..11..  MMEETTAAFFOONNTT IInnssttrruuccttiioonnss



                  - Set your terminal to METAFONT:
                    set terminal mf
                  - Select an output-file, e.g.:
                    set output "myfigures.mf"
                  - Create your pictures. Each picture will generate a
                  separate character. Its default size will be 5*3
                  inches. You can change the size by saying sseett ssiizzee
                  00..55,,00..55 or whatever fraction of the default size you
                  want to have.

                  - Quit ggnnuupplloott.

                  - Generate a TFM and GF file by running METAFONT on
                  the output of ggnnuupplloott.  Since the picture is quite
                  large (5*3 in), you will have to use a version of
                  METAFONT that has a value of at least 150000 for mem-
                  max.  On Unix systems these are conventionally
                  installed under the name bigmf.  For the following
                  assume that the command virmf stands for a big ver-
                  sion of METAFONT.  For example:

                  - Invoke METAFONT:
                      virmf '&plain'
                  - Select the output device: At the METAFONT prompt
                  ('*') type:
                      \mode:=CanonCX;     % or whatever printer you use
                  - Optionally select a magnification:
                      mag:=1;             % or whatever you wish
                  - Input the ggnnuupplloott-file:
                      input myfigures.mf
                  On a typical Unix machine there will usually be a
                  script called "mf" that executes virmf '&plain', so
                  you probably can substitute mf for virmf &plain.
                  This will generate two files: mfput.tfm and










   GNUPLOT 4.1                                                      315


                  mfput.$$$gf (where $$$ indicates the resolution of
                  your device).  The above can be conveniently achieved
                  by typing everything on the command line, e.g.: virmf
                  '&plain' '\mode:=CanonCX; mag:=1; input myfigures.mf'
                  In this case the output files will be named myfig-
                  ures.tfm and myfigures.300gf.

                  - Generate a PK file from the GF file using gftopk:
                    gftopk myfigures.300gf myfigures.300pk
                  The name of the output file for gftopk depends on the
                  DVI driver you use.  Ask your local TeX administrator
                  about the naming conventions.  Next, either install
                  the TFM and PK files in the appropriate directories,
                  or set your environment variables properly.  Usually
                  this involves setting TEXFONTS to include the current
                  directory and doing the same thing for the environ-
                  ment variable that your DVI driver uses (no standard
                  name here...).  This step is necessary so that TeX
                  will find the font metric file and your DVI driver
                  will find the PK file.

                  - To include your pictures in your document you have
                  to tell TeX the font:
                    \font\gnufigs=myfigures
                  Each picture you made is stored in a single charac-
                  ter.  The first picture is character 0, the second is
                  character 1, and so on...  After doing the above
                  step, you can use the pictures just like any other
                  characters.  Therefore, to place pictures 1 and 2
                  centered in your document, all you have to do is:
                    \centerline{\gnufigs\char0}
                    \centerline{\gnufigs\char1}
                  in plain TeX.  For LaTeX you can, of course, use the
                  picture environment and place the picture wherever
                  you wish by using the \makebox and \put macros.

                  This conversion saves you a lot of time once you have
                  generated the font; TeX handles the pictures as char-
                  acters and uses minimal time to place them, and the
                  documents you make change more often than the pic-
                  tures do.  It also saves a lot of TeX memory.  One
                  last advantage of using the METAFONT driver is that
                  the DVI file really remains device independent,
                  because no \special commands are used as in the eepic
                  and tpic drivers.



             9955..4411..  MMiiff


             The mmiiff terminal driver produces Frame Maker MIF format
             version 3.00.  It plots in MIF Frames with the size 15*10










   GNUPLOT 4.1                                                      316


             cm, and plot primitives with the same pen will be grouped
             in the same MIF group.  Plot primitives in a ggnnuupplloott page
             will be plotted in a MIF Frame, and several MIF Frames are
             collected in one large MIF Frame.  The MIF font used for
             text is "Times".

             Several options may be set in the MIF 3.00 driver.

             Syntax:
                   set terminal mif {color | colour | monochrome}
             {polyline | vectors}
                                    {help | ?}

             ccoolloouurr plots lines with line types >= 0 in colour (MIF
             sep. 2--7) and mmoonnoocchhrroommee plots all line types in black
             (MIF sep. 0).  ppoollyylliinnee plots curves as continuous curves
             and vveeccttoorrss plots curves as collections of vectors.  hheellpp
             and ?? print online help on standard error output---both
             print a short description of the usage; hheellpp also lists
             the options.

             Examples:
                   set term mif colour polylines    # defaults
                   set term mif                     # defaults
                   set term mif vectors
                   set term mif help



             9955..4422..  MMpp



             The mmpp driver produces output intended to be input to the
             Metapost program.  Running Metapost on the file creates
             EPS files containing the plots. By default, Metapost
             passes all text through TeX.  This has the advantage of
             allowing essentially  any TeX symbols in titles and
             labels.

             Syntax:
                set term mp {color | colour | monochrome}
                            {solid | dashed}
                            {notex | tex | latex}
                            {magnification <magsize>}
                            {psnfss | psnfss-version7 | nopsnfss}
                            {prologues <value>}
                            {a4paper}
                            {amstex}
                            {"<fontname> {,<fontsize>}"}

             The option ccoolloorr causes lines to be drawn in color (on a
             printer or display that supports it), mmoonnoocchhrroommee (or










   GNUPLOT 4.1                                                      317


             nothing) selects black lines.  The option ssoolliidd draws
             solid lines, while ddaasshheedd (or nothing) selects lines with
             different patterns of dashes.  If ssoolliidd is selected but
             ccoolloorr is not, nearly all lines will be identical.  This
             may occasionally be useful, so it is allowed.

             The option nnootteexx bypasses TeX entirely, therefore no TeX
             code can be used in labels under this option.  This is
             intended for use on old plot files or files that make fre-
             quent use of common characters like $$ and %% that require
             special handling in TeX.

             The option tteexx sets the terminal to output its text for
             TeX to process.

             The option llaatteexx sets the terminal to output its text for
             processing by LaTeX. This allows things like \frac for
             fractions which LaTeX knows about but TeX does not.  Note
             that you must set the environment variable TEX to the name
             of your LaTeX executable (normally latex) if you use this
             option or use mmppoosstt ----tteexx==<<nnaammee ooff LLaaTTeeXX eexxeeccuuttaabbllee>> .......
             Otherwise metapost will try and use TeX to process the
             text and it won't work.

             Changing font sizes in TeX has no effect on the size of
             mathematics, and there is no foolproof way to make such a
             change, except by globally  setting a magnification fac-
             tor. This is the purpose of the mmaaggnniiffiiccaattiioonn option. It
             must be followed by a scaling factor. All text (NOT the
             graphs) will be scaled by this factor. Use this if you
             have math that you want at some size other than the
             default 10pt. Unfortunately, all math will be the same
             size, but see the discussion below on editing the MP out-
             put. mmaagg will also work under nnootteexx but there seems no
             point in using it as the font size option (below) works as
             well.

             The option ppssnnffssss uses postscript fonts in combination
             with LaTeX. Since this option only makes sense, if LaTeX
             is being used, the llaatteexx option is selected automatically.
             This option includes the following packages for LaTeX:
             inputenc(latin1), fontenc(T1), mathptmx, hel-
             vet(scaled=09.2), courier, latexsym and textcomp.

             The option ppssnnffssss--vveerrssiioonn77 uses also postscript fonts in
             LaTeX (option llaatteexx is also automatically selected), but
             uses the following packages with LaTeX: inputenc(latin1),
             fontenc(T1), times, mathptmx, helvet and courier.

             The option nnooppssnnffssss is the default and uses the standard
             font (cmr10 if not otherwise specified).

             The option pprroolloogguueess takes a value as an additional










   GNUPLOT 4.1                                                      318


             argument and adds the line pprroolloogguueess::==<<vvaalluuee>> to the meta-
             post file. If a value of 22 is specified metapost uses
             postscript fonts to generate the eps-file, so that the
             result can be viewed using e.g. ghostscript. Normally the
             output of metapost uses TeX fonts and therefore has to be
             included in a (La)TeX file before you can look at it.

             The option nnoopprroolloogguueess is the default. No additional line
             specifying the prologue will be added.

             The option aa44ppaappeerr adds a [[aa44ppaappeerr]] to the documentclass.
             Normally letter paper is used (default). Since this option
             is only used in case of LaTeX, the llaatteexx option is
             selected automatically.

             The option aammsstteexx automatically selects the llaatteexx option
             and includes the following LaTeX packages: amsfonts, ams-
             math(intlimits). By default these packages are not
             included.

             A name in quotes selects the font that will be used when
             no explicit font is given in a sseett llaabbeell or sseett ttiittllee.  A
             name recognized by TeX (a TFM file exists) must be used.
             The default is "cmr10" unless nnootteexx is selected, then it
             is "pcrr8r" (Courier).  Even under nnootteexx, a TFM file is
             needed by Metapost. The file ppccrrrr88rr..ttffmm is the name given
             to Courier in LaTeX's psnfss package.  If you change the
             font from the nnootteexx default, choose a font that matches
             the ASCII encoding at least in the range 32-126.  ccmmtttt1100
             almost works, but it has a nonblank character in position
             32 (space).

             The size can be any number between 5.0 and 99.99.  If it
             is omitted, 10.0 is used.  It is advisable to use mmaaggsstteepp
             sizes: 10 times an integer or half-integer power of 1.2,
             rounded to two decimals, because those are the most avail-
             able sizes of fonts in TeX systems.

             All the options are optional.  If font information is
             given, it must be at the end, with size (if present) last.
             The size is needed to select a size for the font, even if
             the font name includes size information.  For example, sseett
             tteerrmm mmpp ""ccmmtttt1122"" selects cmtt12 shrunk to the default size
             10.  This is probably not what you want or you would have
             used cmtt10.

             The following common ascii characters need special treat-
             ment in TeX:
                $, &, #, %, _;  |, <, >;  ^, ~,  \, {, and }
             The five characters $, #, &, _, and % can simply be
             escaped, e.g., \\$$.  The three characters <, >, and | can
             be wrapped in math mode, e.g., $$<<$$.  The remainder require
             some TeX work-arounds.  Any good book on TeX will give










   GNUPLOT 4.1                                                      319


             some guidance.

             If you type your labels inside double quotes, backslashes
             in TeX code need to be escaped (doubled). Using single
             quotes will avoid having to do this, but then you cannot
             use \\nn for line breaks.  As of this writing, version 3.7
             of gnuplot processes titles given in a pplloott command dif-
             ferently than in other places, and backslashes in TeX com-
             mands need to be doubled regardless of the style of
             quotes.

             Metapost pictures are typically used in TeX documents.
             Metapost deals with fonts pretty much the same way TeX
             does, which is different from most other document prepara-
             tion programs.  If the picture is included in a LaTeX doc-
             ument using the graphics package, or in a plainTeX docu-
             ment via epsf.tex, and then converted to PostScript with
             dvips (or other dvi-to-ps converter), the text in the plot
             will usually be handled correctly.  However, the text may
             not appear if you send the Metapost output as-is to a
             PostScript interpreter.





                  9955..4422..11..  MMeettaappoosstt IInnssttrruuccttiioonnss



                  - Set your terminal to Metapost, e.g.:
                     set terminal mp mono "cmtt12" 12

                  - Select an output-file, e.g.:
                     set output "figure.mp"

                  - Create your pictures.  Each plot (or multiplot
                  group) will generate a separate Metapost begin-
                  fig...endfig group.  Its default size will be 5 by 3
                  inches.  You can change the size by saying sseett ssiizzee
                  00..55,,00..55 or whatever fraction of the default size you
                  want to have.

                  - Quit gnuplot.

                  - Generate EPS files by running Metapost on the out-
                  put of gnuplot:
                     mpost figure.mp  OR  mp figure.mp
                  The name of the Metapost program depends on the sys-
                  tem, typically mmppoosstt for a Unix machine and mmpp on
                  many others.  Metapost will generate one EPS file for
                  each picture.











   GNUPLOT 4.1                                                      320


                  - To include your pictures in your document you can
                  use the graphics package in LaTeX or epsf.tex in
                  plainTeX:
                     \usepackage{graphics} % LaTeX
                     \input epsf.tex       % plainTeX
                  If you use a driver other than dvips for converting
                  TeX DVI output to PS, you may need to add the follow-
                  ing line in your LaTeX document:
                     \DeclareGraphicsRule{*}{eps}{*}{}
                  Each picture you made is in a separate file.  The
                  first picture is in, e.g., figure.0, the second in
                  figure.1, and so on....  To place the third picture
                  in your document, for example, all you have to do is:
                     \includegraphics{figure.2} % LaTeX
                     \epsfbox{figure.2}         % plainTeX

                  The advantage, if any, of the mp terminal over a
                  postscript terminal is editable output.  Considerable
                  effort went into making this output as clean as pos-
                  sible.  For those knowledgeable in the Metapost lan-
                  guage, the default line types and colors can be
                  changed by editing the arrays lltt[[]] and ccooll[[]].  The
                  choice of solid vs dashed lines, and color vs black
                  lines can be change by changing the values assigned
                  to the booleans ddaasshheeddlliinneess and ccoolloorrlliinneess.  If the
                  default tteexx option was in effect, global changes to
                  the text of labels can be achieved by editing the
                  vveebbaattiimmtteexx......eetteexx block.  In particular, a LaTeX pre-
                  amble can be added if desired, and then LaTeX's
                  built-in size changing commands can be used for maxi-
                  mum flexibility. Be sure to set the appropriate MP
                  configuration variable to force Metapost to run LaTeX
                  instead of plainTeX.



             9955..4433..  NNeexxtt


             Several options may be set in the next driver.

             Syntax:
                   set terminal next {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  ddeeffaauulltt, which sets all options to their
             defaults; <type> is either nneeww or oolldd, where oolldd invokes
             the old single window; <color> is either ccoolloorr or mmoonnoo--
             cchhrroommee; <dashed> is either ssoolliidd or ddaasshheedd; "<fontname>"
             is the name of a valid PostScript font; <fontsize> is the
             size of the font in PostScript points; and <title> is the










   GNUPLOT 4.1                                                      321


             title for the GnuTerm window.  Defaults are  nneeww, mmoonnoo--
             cchhrroommee, ddaasshheedd, "Helvetica", 14pt.

             Examples:
                   set term next default
                   set term next 22
                   set term next color "Times-Roman" 14
                   set term next color "Helvetica" 12 title "MyPlot"
                   set term next old

             Pointsizes may be changed with sseett lliinneessttyyllee.



             9955..4444..  OOppeennsstteepp ((nneexxtt))


             Several options may be set in the openstep (next) driver.

             Syntax:
                   set terminal openstep {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  ddeeffaauulltt, which sets all options to their
             defaults; <type> is either nneeww or oolldd, where oolldd invokes
             the old single window; <color> is either ccoolloorr or mmoonnoo--
             cchhrroommee; <dashed> is either ssoolliidd or ddaasshheedd; "<fontname>"
             is the name of a valid PostScript font; <fontsize> is the
             size of the font in PostScript points; and <title> is the
             title for the GnuTerm window.  Defaults are  nneeww, mmoonnoo--
             cchhrroommee, ddaasshheedd, "Helvetica", 14pt.

             Examples:
                   set term openstep default
                   set term openstep 22
                   set term openstep color "Times-Roman" 14
                   set term openstep color "Helvetica" 12 title
             "MyPlot"
                   set term openstep old

             Pointsizes may be changed with sseett lliinneessttyyllee.



             9955..4455..  PPbbmm


             Syntax:
                   set terminal pbm {<fontsize>} {<mode>} {size
             <x>,<y>}











   GNUPLOT 4.1                                                      322


             where <fontsize> is ssmmaallll, mmeeddiiuumm, or llaarrggee and <mode> is
             mmoonnoocchhrroommee, ggrraayy or ccoolloorr.  The default plot size is 640
             pixels wide and 480 pixels high. The output size is white-
             space padded to the nearest multiple of 8 pixels on both x
             and y. This empty space may be cropped later if needed.

             The output of the ppbbmm driver depends upon <mode>: mmoonnoo--
             cchhrroommee produces a portable bitmap (one bit per pixel),
             ggrraayy a portable graymap (three bits per pixel) and ccoolloorr a
             portable pixmap (color, four bits per pixel).

             The output of this driver can be used with various image
             conversion and manipulation utilities provided by NETPBM.
             Based on Jef Poskanzer's PBMPLUS package, NETPBM provides
             programs to convert the above PBM formats to GIF, TIFF,
             MacPaint, Macintosh PICT, PCX, X11 bitmap and many others.
             Complete information is available at http://netpbm.source-
             forge.net/.

             Examples:
                   set terminal pbm small monochrome                #
             defaults
                   set terminal pbm color medium size 800,600
                   set output '| pnmrotate 45 | pnmtopng > tilted.png'
             # uses NETPBM



             9955..4466..  PPddff


             This terminal produces files in the Adobe Portable Docu-
             ment Format (PDF), useable for printing or display with
             tools like Acrobat Reader

             Syntax:
                   set terminal pdf {monochrome|color|colour}
                                    {{no}enhanced}
                                    {fname "<font>"} {fsize <fontsize>}
                                    {font "<fontname>{,<fontsize>}"}
             {fontscale <scale>}
                                    {linewidth <lw>} {rounded|butt}
                                    {solid|dashed} {dl <dashlength>}}
                                    {size <XX>{unit},<YY>{unit}}

             The default is to use a different color for each line
             type. Selecting mmoonnoocchhoommee will use black for all line-
             types, in which case you probably want to select ddaasshheedd to
             distinguish line types. Even in in mono mode you can still
             use explicit colors for filled areas or linestyles.

             where <font> is the name of the default font to use
             (default Helvetica) and <fontsize> is the font size (in










   GNUPLOT 4.1                                                      323


             points, default 12).  For help on which fonts are avail-
             able or how to install new ones, please see the documenta-
             tion for your local installation of pdflib.

             The eennhhaanncceedd option enables enhanced text processing fea-
             tures (subscripts, superscripts and mixed fonts). See
             eennhhaanncceedd.

             The width of all lines in the plot can be increased by the
             factor <n> specified in lliinneewwiiddtthh. Similarly ddaasshhlleennggtthh is
             a multiplier for the default dash spacing.

             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.

             The default size for PDF output is 5 inches by 3 inches.
             The ssiizzee option changes this to whatever the user
             requests. By default the X and Y sizes are taken to be in
             inches, but other units are possible (currently only cm).




             9955..4477..  PPddffccaaiirroo


             The ppddffccaaiirroo terminal device generates output in pdf. The
             actual drawing is done via cairo, a 2D graphics library,
             and pango, a library for laying out and rendering text.

             Syntax:
                     set term pdfcairo
                                  {{no}enhanced} {mono|color}
             {solid|dashed}
                                  {font <font>} {fontscale <scale>}
                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See eennhhaanncceedd for more
             details.

             The width of all lines in the plot can be modified by the
             factor <lw> specified in lliinneewwiiddtthh. The default linewidth
             is 0.25 points.  (1 "PostScript" point = 1/72 inch = 0.353
             mm)

             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.










   GNUPLOT 4.1                                                      324


             The default size for the output is 5 inches x 3 inches.
             The ssiizzee option changes this to whatever the user
             requests. By default the X and Y sizes are taken to be in
             inches, but other units are possible (currently only cm).
             Screen coordinates always run from 0.0 to 1.0 along the
             full length of the plot edges as specified by the ssiizzee
             option.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the pdfcairo terminal will use 'Sans'.
             FontSize is the font size, in points. If you do not pro-
             vide it, the pdfcairo terminal will use a nominal font
             size of 12 points.  However, the default fontscale parame-
             ter for this terminal is 0.5, so the apparent font size is
             smaller than this if the pdf output is viewed at full
             size.
                For example :
                   set term pdfcairo font "Arial,12"
                   set term pdfcairo font "Arial" # to change the font
             face only
                   set term pdfcairo font ",12" # to change the font
             size only
                   set term pdfcairo font "" # to reset the font name
             and size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".

             Pango, the library used to layout the text, is based on
             utf-8. Thus, the pdfcairo terminal has to convert from
             your encoding to utf-8. The default input encoding is
             based on your 'locale'. If you want to use another encod-
             ing, make sure gnuplot knows which one you are using. See
             eennccooddiinngg for more details.

             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the pdfcairo terminal will use the map provided
             by http://www.unicode.org/ to translate character codes to
             unicode.  Note that "the Symbol font" is to be understood
             as the Adobe Symbol font, distributed with Acrobat Reader
             as "SY______.PFB".  Alternatively, the OpenSymbol font,
             distributed with OpenOffice.org as "opens___.ttf", offers
             the same characters. Microsoft has distributed a Symbol
             font ("symbol.ttf"), but it has a different character set
             with several missing or moved mathematic characters. If
             you experience problems with your default setup (if the
             demo enhancedtext.dem is not displayed properly for exam-
             ple), you probably have to install one of the Adobe or










   GNUPLOT 4.1                                                      325


             OpenOffice Symbol fonts, and remove the Microsoft one.
             Other non-conform fonts, such as "wingdings" have been
             observed working.

             The rendering of the plot cannot be altered yet. To obtain
             the best output possible, the rendering involves two mech-
             anisms : antialiasing and oversampling.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).




             9955..4488..  PPmm


             The ppmm terminal driver provides an OS/2 Presentation Man-
             ager window in which the graph is plotted.  The window is
             opened when the first graph is plotted.  This window has
             its own online help as well as facilities for printing,
             copying to the clipboard and some line type and color
             adjustments.  The mmuullttiipplloott option is supported.

             Syntax:
                   set terminal pm {server {n}} {persist} {widelines}
             {enhanced} {"title"}

             If ppeerrssiisstt is specified, each graph appears in its own
             window and all windows remain open after ggnnuupplloott exits.
             If sseerrvveerr is specified, all graphs appear in the same win-
             dow, which remains open when ggnnuupplloott exits.  This option
             takes an optional numerical argument which specifies an
             instance of the server process.  Thus multiple server win-
             dows can be in use at the same time.

             If wwiiddeelliinneess is specified, all plots will be drawn with
             wide lines.  If eennhhaanncceedd is specified, sub- and super-
             scripts and multiple fonts are enabled (see eennhhaanncceedd tteexxtt
             for details).  Font names for the core PostScript fonts
             may be abbreviated to a single letter (T/H/C/S for
             Times/Helvetica/Courier/Symbol).

             If ttiittllee is specified, it will be used as the title of the
             plot window.  It will also be used as the name of the
             server instance, and will override the optional numerical
             argument.

             Linewidths may be changed with sseett lliinneessttyyllee.












   GNUPLOT 4.1                                                      326


             9955..4499..  PPnngg


             Syntax:
                   set terminal png
                          {{no}enhanced}
                          {{no}transparent} {{no}interlace}
                          {{no}truecolor} {rounded|butt}
                          {linewidth <lw>} {dashlength <dl>}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  PNG plots may be viewed interactively by
             piping the output to the 'display' program from the
             ImageMagick package as follows:
                            set term png
                            set output '| display png:-'
             You can view the output from successive plot commands
             interactively by typing <space> in the display window.  To
             save the current plot to a file, left click in the display
             window and choose ssaavvee.

             ttrraannssppaarreenntt instructs the driver to make the background
             color transparent.  Default is nnoottrraannssppaarreenntt.

             iinntteerrllaaccee instructs the driver to generate interlaced
             PNGs.  Default is nnooiinntteerrllaaccee.

             The lliinneewwiiddtthh and ddaasshhlleennggtthh options are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.

             By default output png images use 256 indexed colors. The
             ttrruueeccoolloorr option instead creates TrueColor images with 24
             bits of color information per pixel.  Transparent fill
             styles require the ttrruueeccoolloorr option. See ffiillllssttyyllee.  A
             transparent background is possible in either indexed or
             TrueColor images.

             bbuutttt instructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is rroouunnddeedd.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term png font arial 11
                  set term png font "arial,11"










   GNUPLOT 4.1                                                      327


             For more information please see the separate section under
             ffoonnttss.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under ccaannvvaass and sseett ssiizzee.  Blank space at the edges of
             the finished plot may be trimmed using the ccrroopp option,
             resulting in a smaller final image size. Default is
             nnooccrroopp.





                  9955..4499..11..  EExxaammpplleess


                        set terminal png medium size 640,480 background
                  '#ffffff'

                  Use the medium size built-in non-scaleable, non-
                  rotatable font.  Use white (24-bit RGB in hexadeci-
                  mal) for the non-transparent background.

                        set terminal png font arial 14 size 800,600

                  Searches for a scalable font with face name 'arial'
                  and sets the font size to 14pt.  Please see ffoonnttss for
                  details of how the font search is done.

                        set terminal png transparent truecolor enhanced

                  Use 24 bits of color information per pixel, with a
                  transparent background.  Use the eennhhaanncceedd tteexxtt mode
                  to control the layout of strings to be printed.




             9955..5500..  PPnnggccaaiirroo


             The ppnnggccaaiirroo terminal device generates output in png. The
             actual drawing is done via cairo, a 2D graphics library,
             and pango, a library for laying out and rendering text.

             Syntax:
                     set term pngcairo
                                  {{no}enhanced} {mono|color}
             {solid|dashed}
                                  {{no}transparent} {{no}crop} {back-
             ground <rgbcolor>
                                  {font <font>} {fontscale <scale>}










   GNUPLOT 4.1                                                      328


                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See eennhhaanncceedd for more
             details.

             The width of all lines in the plot can be modified by the
             factor <lw>.

             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.

             The default size for the output is 640 x 480 pixels. The
             ssiizzee option changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in pixels, but
             other units are possible (currently cm and inch).  A size
             given in centimeters or inches will be converted into pix-
             els assuming a resolution of 72 dpi. Screen coordinates
             always run from 0.0 to 1.0 along the full length of the
             plot edges as specified by the ssiizzee option.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the pngcairo terminal will use 'Sans'.
             FontSize is the font size, in points. If you do not pro-
             vide it, the pngcairo terminal will use a size of 12
             points.
                For example :
                   set term pngcairo font "Arial,12"
                   set term pngcairo font "Arial" # to change the font
             face only
                   set term pngcairo font ",12" # to change the font
             size only
                   set term pngcairo font "" # to reset the font name
             and size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".

             Pango, the library used to layout the text, is based on
             utf-8. Thus, the pngcairo terminal has to convert from
             your encoding to utf-8. The default input encoding is
             based on your 'locale'. If you want to use another encod-
             ing, make sure gnuplot knows which one you are using. See
             eennccooddiinngg for more details.










   GNUPLOT 4.1                                                      329


             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the pngcairo terminal will use the map provided
             by http://www.unicode.org/ to translate character codes to
             unicode.  Note that "the Symbol font" is to be understood
             as the Adobe Symbol font, distributed with Acrobat Reader
             as "SY______.PFB".  Alternatively, the OpenSymbol font,
             distributed with OpenOffice.org as "opens___.ttf", offers
             the same characters. Microsoft has distributed a Symbol
             font ("symbol.ttf"), but it has a different character set
             with several missing or moved mathematic characters. If
             you experience problems with your default setup (if the
             demo enhancedtext.dem is not displayed properly for exam-
             ple), you probably have to install one of the Adobe or
             OpenOffice Symbol fonts, and remove the Microsoft one.
             Other non-conform fonts, such as "wingdings" have been
             observed working.

             The rendering of the plot cannot be altered yet. To obtain
             the best output possible, the rendering involves two mech-
             anisms : antialiasing and oversampling.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).




             9955..5511..  PPoossttssccrriipptt


             Several options may be set in the ppoossttssccrriipptt driver.

             Syntax:
                   set terminal postscript {default}
                   set terminal postscript {landscape | portrait | eps}
                                           {enhanced | noenhanced}
                                           {defaultplex | simplex |
             duplex}
                                           {fontfile [add | delete]
             "<filename>"
                                            | nofontfiles} {{no}adobeg-
             lyphnames}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}










   GNUPLOT 4.1                                                      330


                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam <sam-
             ples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {blacktext | colortext |
             colourtext}
                                           {{font} "fontname{,font-
             size}" {<fontsize>}}
                                           {fontscale <scale>}
             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in ppoossttssccrriipptt pprroo--
             lloogguuee.


             llaannddssccaappee and ppoorrttrraaiitt choose the plot orientation.  eeppss
             mode generates EPS (Encapsulated PostScript) output, which
             is just regular PostScript with some additional lines that
             allow the file to be imported into a variety of other
             applications.  (The added lines are PostScript comment
             lines, so the file may still be printed by itself.)  To
             get EPS output, use the eeppss mode and make only one plot
             per file.  In eeppss mode the whole plot, including the
             fonts, is reduced to half of the default size.

             eennhhaanncceedd enables enhanced text mode features (subscripts,
             superscripts and mixed fonts). See eennhhaanncceedd for more
             information.  bbllaacckktteexxtt forces all text to be written in
             black even in color mode;

             Duplexing in PostScript is the ability of the printer to
             print on both sides of the same sheet of paper.  With
             ddeeffaauullttpplleexx, the default setting of the printer is used;
             with ssiimmpplleexx only one side is printed; dduupplleexx prints on
             both sides (ignored if your printer can't do it).

             ""<<ffoonnttnnaammee>>"" is the name of a valid PostScript font; and
             <<ffoonnttssiizzee>> is the size of the font in PostScript points.
             In addition to the standard postscript fonts, an oblique
             version of the Symbol font, useful for mathematics, is
             defined. It is called "Symbol-Oblique".

             ddeeffaauulltt sets all options to their defaults: llaannddssccaappee,
             mmoonnoocchhrroommee, ddaasshheedd, ddll 11..00, llww 11..00, ddeeffaauullttpplleexx, nnooeenn--
             hhaanncceedd, "Helvetica" and 14pt.  Default size of a Post-
             Script plot is 10 inches wide and 7 inches high.  The
             option ccoolloorr enables color, while mmoonnoocchhrroommee prefers black
             and white drawing elements. Further, mmoonnoocchhrroommee uses gray
             ppaalleettttee but it does not change color of objects specified
             with an explicit ccoolloorrssppeecc.  ssoolliidd draws all plots with
             solid lines, overriding any dashed patterns.  ddaasshhlleennggtthh
             or ddll scales the length of the dashed-line segments by










   GNUPLOT 4.1                                                      331


             <DL>, which is a floating-point number greater than zero.
             lliinneewwiiddtthh or llww scales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The lleevveell11 option sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag lleevveell11 can be toggled later by
             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.

             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.

             cclliipp tells PostScript to clip all output to the bounding
             box; nnoocclliipp is the default.

             ppaallffuunnccppaarraamm controls how sseett ppaalleettttee ffuunnccttiioonnss are
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via sseett ppaalleettttee ffuunnccttiioonnss) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             ssiizzee option changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the ssiizzee option.  NB: tthhiiss iiss aa cchhaannggee ffrroomm tthhee pprreevvii--
             oouussllyy rreeccoommmmeennddeedd mmeetthhoodd ooff uussiinngg tthhee sseett ssiizzee ccoommmmaanndd
             pprriioorr ttoo sseettttiinngg tthhee tteerrmmiinnaall ttyyppee.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             Fonts listed by ffoonnttffiillee or ffoonnttffiillee aadddd encapsulate the










   GNUPLOT 4.1                                                      332


             font definitions of the listed font from a postscript Type
             1 or TrueType font file directly into the gnuplot output
             postscript file.  Thus, the enclosed font can be used in
             labels, titles, etc.  See the section ppoossttssccrriipptt ffoonnttffiillee
             for more details.  With ffoonnttffiillee ddeelleettee, a fontfile is
             deleted from the list of embedded files.  nnooffoonnttffiilleess
             cleans the list of embedded fonts.

             Examples:
                   set terminal postscript default       # old post-
             script
                   set terminal postscript enhanced      # old enhpost
                   set terminal postscript landscape 22  # old psbig
                   set terminal postscript eps 14        # old epsf1
                   set terminal postscript eps 22        # old epsf2
                   set size 0.7,1.4; set term post portrait color
             "Times-Roman" 14
                   set term post "VAGRoundedBT_Regular" 14 fontfile
             "bvrr8a.pfa"

             Linewidths and pointsizes may be changed with sseett ssttyyllee
             lliinnee.

             The ppoossttssccrriipptt driver supports about 70 distinct point-
             types, selectable through the ppooiinnttttyyppee option on pplloott and
             sseett ssttyyllee lliinnee.

             Several possibly useful files about ggnnuupplloott's PostScript
             are included in the /docs/psdoc subdirectory of the ggnnuu--
             pplloott distribution and at the distribution sites.  These
             are "ps_symbols.gpi" (a ggnnuupplloott command file that, when
             executed, creates the file "ps_symbols.ps" which shows all
             the symbols available through the ppoossttssccrriipptt terminal),
             "ps_guide.ps" (a PostScript file that contains a summary
             of the enhanced syntax and a page showing what the octal
             codes produce with text and symbol fonts), "ps_file.doc"
             (a text file that contains a discussion of the organiza-
             tion of a PostScript file written by ggnnuupplloott), and
             "ps_fontfile_doc.tex" (a LaTeX file which contains a short
             documentation concerning the encapsulation of LaTeX fonts
             with a glyph table of the math fonts).

             A PostScript file is editable, so once ggnnuupplloott has created
             one, you are free to modify it to your heart's desire.
             See the eeddiittiinngg ppoossttssccrriipptt section for some hints.




                  9955..5511..11..  EEddiittiinngg ppoossttssccrriipptt













   GNUPLOT 4.1                                                      333


                  The PostScript language is a very complex lan-
                  guage---far too complex to describe in any detail in
                  this document.  Nevertheless there are some things in
                  a PostScript file written by ggnnuupplloott that can be
                  changed without risk of introducing fatal errors into
                  the file.

                  For example, the PostScript statement "/Color true
                  def" (written into the file in response to the com-
                  mand sseett tteerrmmiinnaall ppoossttssccrriipptt ccoolloorr), may be altered
                  in an obvious way to generate a black-and-white ver-
                  sion of a plot.  Similarly line colors, text colors,
                  line weights and symbol sizes can also be altered in
                  straight-forward ways.  Text (titles and labels) can
                  be edited to correct misspellings or to change fonts.
                  Anything can be repositioned, and of course anything
                  can be added or deleted, but modifications such as
                  these may require deeper knowledge of the PostScript
                  language.

                  The organization of a PostScript file written by ggnnuu--
                  pplloott is discussed in the text file "ps_file.doc" in
                  the docs/ps subdirectory of the gnuplot source dis-
                  tribution.



                  9955..5511..22..  PPoossttssccrriipptt ffoonnttffiillee


                  The ffoonnttffiillee or ffoonnttffiillee aadddd option takes one file
                  name as argument and encapsulates this file into the
                  postscript output in order to make this font avail-
                  able for text elements (labels, tic marks, titles,
                  etc.).  The ffoonnttffiillee ddeelleettee option also takes one
                  file name as argument. It deletes this file name from
                  the list of encapsulated files.

                  The postscript terminal understands some font file
                  formats: Type 1 fonts in ASCII file format (extension
                  ".pfa"), Type 1 fonts in binary file format (exten-
                  sion ".pfb"), and TrueType fonts (extension ".ttf").
                  Pfa files are understood directly, pfb and ttf files
                  are converted on the fly if appropriate conversion
                  tools are installed (see below). You have to specify
                  the full filename including the extension. Each ffoonntt--
                  ffiillee option takes exact one font file name. This
                  option can be used multiple times in order to include
                  more than one font file.

                  The font file is searched in the working directory
                  and in all directories listed in the fontpath which
                  is determined by sseett ffoonnttppaatthh.  In addition, the










   GNUPLOT 4.1                                                      334


                  fontpath can be set using the environment variable
                  GNUPLOT_FONTPATH. If this is not set a system depen-
                  dent default search list is used. See sseett ffoonnttppaatthh
                  for more details.

                  For using the encapsulated font file you have to
                  specify the font name (which normally is not the same
                  as the file name). When embedding a font file by
                  using the ffoonnttffiillee option in interactive mode, the
                  font name is printed on the screen. E.g.
                     Font file 'p052004l.pfb' contains the font 'URW-
                  PalladioL-Bold'. Location:
                     /usr/lib/X11/fonts/URW/p052004l.pfb

                  When using pfa or pfb fonts, you can also find it out
                  by looking into the font file. There is a line simi-
                  lar to "/FontName /URWPalladioL-Bold def".  The mid-
                  dle string without the slash is the fontname, here
                  "URWPalladioL-Bold".  For TrueType fonts, this is not
                  so easy since the font name is stored in a binary
                  format. In addition, they often have spaces in the
                  font names which is not supported by Type 1 fonts (in
                  which a TrueType is converted on the fly). The font
                  names are changed in order to eliminate the spaces in
                  the fontnames. The easiest way to find out which font
                  name is generated for use with gnuplot, start gnuplot
                  in interactive mode and type in "set terminal post-
                  script fontfile '<filename.ttf>'".

                  For converting font files (either ttf or pfb) to pfa
                  format, the conversion tool has to read the font from
                  a file and write it to standard output. If the output
                  cannot be written to standard output, on-the-fly con-
                  version is not possible.

                  For pfb files "pfbtops" is a tool which can do this.
                  If this program is installed on your system the on
                  the fly conversion should work.  Just try to encapsu-
                  late a pfb file. If the compiled in program call does
                  not work correctly you can specify how this program
                  is called by defining the environment variable GNU-
                  PLOT_PFBTOPFA e.g. to "pfbtops %s". The %%ss will be
                  replaced by the font file name and thus has to exist
                  in the string.

                  If you don't want to do the conversion on the fly but
                  get a pfa file of the font you can use the tool
                  "pfb2pfa" which is written in simple c and should
                  compile with any c compiler.  It is available from
                  many ftp servers, e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/utili-
                  ties/ps2mf/
                  In fact, "pfbtopfa" and "pfb2ps" do the same job.










   GNUPLOT 4.1                                                      335


                  "pfbtopfa" puts the resulting pfa code into a file,
                  whereas "pfbtops" writes it to standard output.

                  TrueType fonts are converted into Type 1 pfa format,
                  e.g.  by using the tool "ttf2pt1" which is available
                  from
                            http://ttf2pt1.sourceforge.net/
                  If the builtin conversion does not work, the conver-
                  sion command can be changed by the environment vari-
                  able GNUPLOT_TTFTOPFA. For usage with ttf2pt1 it may
                  be set to "ttf2pt1 -a -e -W 0 %s - ". Here again, %%ss
                  stands for the file name.

                  For special purposes you also can use a pipe (if
                  available for your operating system). Therefore you
                  start the file name definition with the character "<"
                  and append a program call. This program has to write
                  pfa data to standard output. Thus, a pfa file may be
                  accessed by sseett ffoonnttffiillee ""<< ccaatt ggaarraammoonndd..ppffaa"".

                  For example, including Type 1 font files can be used
                  for including the postscript output in LaTeX docu-
                  ments. The "european computer modern" font (which is
                  a variant of the "computer modern" font) is available
                  in pfb format from any CTAN server, e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/ps-
                  type1/cm-super/
                  For example, the file "sfrm1000.pfb" contains the
                  normal upright fonts with serifs in the design size
                  10pt (font name "SFRM1000").  The computer modern
                  fonts, which are still necessary for mathematics, are
                  available from
                            ftp://ftp.dante.de/tex-archive/fonts/cm/ps-
                  type1/bluesky
                  With these you can use any character available in
                  TeX. However, the computer modern fonts have a
                  strange encoding. (This is why you should not use
                  cmr10.pfb for text, but sfrm1000.pfb instead.)  The
                  usage of TeX fonts is shown in one of the demos.  The
                  file "ps_fontfile_doc.tex" in the /docs/psdoc subdi-
                  rectory of the ggnnuupplloott source distribution contains a
                  table with glyphs of the TeX mathfonts.

                  If the font "CMEX10" is embedded (file "cmex10.pfb")
                  gnuplot defines the additional font "CMEX10-Base-
                  line". It is shifted vertically in order to fit bet-
                  ter to the other glyphs (CMEX10 has its baseline at
                  the top of the symbols).















   GNUPLOT 4.1                                                      336


                  9955..5511..33..  PPoossttssccrriipptt pprroolloogguuee


                  Each PostScript output file includes a %%Prolog sec-
                  tion and possibly some additional user-defined sec-
                  tions containing, for example, character encodings.
                  These sections are copied from a set of PostScript
                  prologue files that are either compiled into the gnu-
                  plot executable or stored elsewhere on your computer.
                  A default directory where these files live is set at
                  the time gnuplot is built. However, you can override
                  this default either by using the gnuplot command sseett
                  ppssddiirr or by defining an environment variable GNU-
                  PLOT_PS_DIR. See sseett ppssddiirr.



                  9955..5511..44..  PPoossttssccrriipptt aaddoobbeeggllyypphhnnaammeess


                  This setting is only relevant to PostScript output
                  with UTF-8 encoding.  It controls the names used to
                  describe characters with Unicode entry points higher
                  than 0x00FF.  That is, all characters outside of the
                  Latin1 set.  In general unicode characters do not
                  have a unique name; they have only a unicode identi-
                  fication code.  However, Adobe have a recommended
                  scheme for assigning names to certain ranges of char-
                  acters (extended Latin, Greek, etc).  Some fonts use
                  this scheme, others do not.  By default, gnuplot will
                  use the Adobe glyph names.  E.g. the lower case Greek
                  letter alpha will be called /alpha.  If you specific
                  nnooaaddoobbeeggllyypphhnnaammeess then instead gnuplot will use
                  /uni03B1 to describe this character.  If you get this
                  setting wrong, the character may not be found even if
                  it is present in the font.  It is probably always
                  correct to use the default for Adobe fonts, but for
                  other fonts you may have to try both settings.  See
                  also ffoonnttffiillee.





             9955..5522..  PPssllaatteexx aanndd ppsstteexx


             The ppssllaatteexx driver generates output for further processing
             by LaTeX, while the ppsstteexx driver generates output for fur-
             ther processing by TeX. ppssllaatteexx uses \specials understand-
             able by dvips and xdvi. Figures generated by ppsstteexx can be
             included in any plain-based format (including LaTeX).











   GNUPLOT 4.1                                                      337


             Syntax:
                   set terminal [pslatex | pstex] {default}
                   set terminal [pslatex | pstex]
                                           {rotate | norotate}
                                           {oldstyle | newstyle}
                                           {auxfile | noauxfile}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}
                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam <sam-
             ples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {<font_size>}

             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in ppoossttssccrriipptt pprroo--
             lloogguuee.

             The option ccoolloorr enables color, while mmoonnoocchhrroommee prefers
             black and white drawing elements. Further, mmoonnoocchhrroommee uses
             gray ppaalleettttee but it does not change color of objects spec-
             ified with an explicit ccoolloorrssppeecc.  ssoolliidd draws all plots
             with solid lines, overriding any dashed patterns.  ddaasshh--
             lleennggtthh or ddll scales the length of the dashed-line segments
             by <DL>, which is a floating-point number greater than
             zero.  lliinneewwiiddtthh or llww scales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The lleevveell11 option sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag lleevveell11 can be toggled later by
             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.











   GNUPLOT 4.1                                                      338


             rroouunnddeedd sets line caps and line joins to be rounded; bbuutttt
             is the default, butt caps and mitered joins.

             cclliipp tells PostScript to clip all output to the bounding
             box; nnoocclliipp is the default.

             ppaallffuunnccppaarraamm controls how sseett ppaalleettttee ffuunnccttiioonnss are
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via sseett ppaalleettttee ffuunnccttiioonnss) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             ssiizzee option changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the ssiizzee option.  NB: tthhiiss iiss aa cchhaannggee ffrroomm tthhee pprreevvii--
             oouussllyy rreeccoommmmeennddeedd mmeetthhoodd ooff uussiinngg tthhee sseett ssiizzee ccoommmmaanndd
             pprriioorr ttoo sseettttiinngg tthhee tteerrmmiinnaall ttyyppee.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             if rroottaattee is specified, the y-axis label is rotated.
             <font_size> is the size (in pts) of the desired font.

             If aauuxxffiillee is specified, it directs the driver to put the
             PostScript commands into an auxiliary file instead of
             directly into the LaTeX file.  This is useful if your pic-
             tures are large enough that dvips cannot handle them.  The
             name of the auxiliary PostScript file is derived from the
             name of the TeX file given on the sseett oouuttppuutt command; it
             is determined by replacing the trailing ..tteexx (actually
             just the final extent in the file name) with ..ppss in the
             output file name, or, if the TeX file has no extension,
             ..ppss is appended.  The ..ppss is included into the ..tteexx file
             by a \special{psfile=...} command.  Remember to close the
             oouuttppuutt ffiillee before next plot unless in mmuullttiipplloott mode.

             Gnuplot versions prior to version 4.2 generated plots of
             the size 5 x 3 inches using the ps(la)tex terminal while
             the current version generates 5 x 3.5 inches to be consis-
             tent with the postscript eps terminal.  In addition, the
             character width is now estimated to be 60% of the font
             size while the old epslatex terminal used 50%. To reach










   GNUPLOT 4.1                                                      339


             the old format specify the option oollddssttyyllee.

             The pslatex driver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             The options not described here are identical to the PPoosstt--
             ssccrriipptt tteerrmmiinnaall.  Look there if you want to know what they
             do.

             Examples:
                   set term pslatex monochrome dashed rotate       #
             set to defaults
             To write the PostScript commands into the file "foo.ps":
                   set term pslatex auxfile
                   set output "foo.tex"; plot ...; set output
             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'

             Linewidths and pointsizes may be changed with sseett ssttyyllee
             lliinnee.



             9955..5533..  PPssttrriicckkss


             The ppssttrriicckkss driver is intended for use with the
             "pstricks.sty" macro package for LaTeX.  It is an alterna-
             tive to the eeeeppiicc and llaatteexx drivers.  You need
             "pstricks.sty", and, of course, a printer that understands
             PostScript, or a converter such as Ghostscript.

             PSTricks is available via anonymous ftp from the /pub
             directory at Princeton.edu.  This driver definitely does
             not come close to using the full capability of the
             PSTricks package.











   GNUPLOT 4.1                                                      340


             Syntax:
                   set terminal pstricks {hacktext | nohacktext} {unit
             | nounit}

             The first option invokes an ugly hack that gives nicer
             numbers; the second has to do with plot scaling.  The
             defaults are hhaacckktteexxtt and nnoouunniitt.



             9955..5544..  QQmmss


             The qqmmss terminal driver supports the QMS/QUIC Laser
             printer, the Talaris 1200 and others.  It has no options.



             9955..5555..  QQtt


             The qqtt terminal device generates output in a separate win-
             dow with the Qt library.  Syntax:
                     set term qt {<n>}
                                 {size <width>,<height>}
                                 {{no}enhanced}
                                 {font <font>}
                                 {title "title"}
                                 {{no}persist}
                                 {{no}raise}
                                 {{no}ctrl}
                                 {close}
                                 {widget <id>}

             Multiple plot windows are supported: sseett tteerrmmiinnaall qqtt <<nn>>
             directs the output to plot window number n.

             The default window title is based on the window number.
             This title can also be specified with the keyword "title".

             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device. A plot window can be closed
             by pressing the letter 'q' while that window has input
             focus, by choosing cclloossee from a window manager menu, or
             with sseett tteerrmm qqtt <<nn>> cclloossee.

             The size of the plot area is given in pixels, it defaults
             to 640x480.  In addition to that, the actual size of the
             window also includes the space reserved for the toolbar
             and the status bar.  When you resize a window, the plot is
             immediately scaled to fit in the new size of the window.
             The qqtt terminal scales the whole plot, including fonts and
             linewidths, and keeps its global aspect ratio constant.










   GNUPLOT 4.1                                                      341


             If you type rreepplloott, click the rreepplloott icon in the terminal
             toolbar or type a new pplloott command, the new plot will com-
             pletely fit in the window and the font size and the
             linewidths will be reset to their defaults.

             The active plot window (the one selected by sseett tteerrmm qqtt
             <<nn>>) is interactive. Its behaviour is shared with other
             terminal types. See mmoouussee for details. It also has some
             extra icons, which are supposed to be self-explanatory.

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See eennhhaanncceedd for more
             details.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the qt terminal will use 'Sans'. Font-
             Size is the font size, in points. If you do not provide
             it, the qt terminal will use a size of 9 points.
                For example :
                   set term qt font "Arial,12"
                   set term qt font "Arial" # to change the font face
             only
                   set term qt font ",12" # to change the font size
             only
                   set term qt font "" # to reset the font name and
             size

             The Qt rendering speed is affected strongly by the render-
             ing mode used.  In Qt version 4.7 or newer this can be
             controlled by the environmental variable QT_GRAPHICSSYS-
             TEM. The options are "native", "raster", or "opengl" in
             order of increasing rendering speed.  For earlier versions
             of Qt the terminal defaults to "raster".

             To obtain the best output possible, the rendering involves
             three mechanisms : antialiasing, oversampling and hinting.
             Oversampling combined with antialiasing provides subpixel
             accuracy, so that gnuplot can draw a line from non-integer
             coordinates. This avoids wobbling effects on diagonal
             lines ('plot x' for example).  Hinting avoids the blur on
             horizontal and vertical lines caused by oversampling. The
             terminal will snap these lines to integer coordinates so
             that a one-pixel-wide line will actually be drawn on one
             and only one pixel.

             By default, the window is raised to the top of your desk-
             top when a plot is drawn. This can be controlled with the
             keyword "raise".  The keyword "persist" will prevent










   GNUPLOT 4.1                                                      342


             gnuplot from exiting before you explicitely close all the
             plot windows.  Finally, by default the key <space> raises
             the gnuplot console window, and 'q' closes the plot win-
             dow. The keyword "ctrl" allows you to replace those bind-
             ings by <ctrl>+<space> and <ctrl>+'q', respectively.

             The gnuplot outboard driver, gnuplot_qt, is searched in a
             default place chosen when the program is compiled.  You
             can override that by defining the environment variable
             GNUPLOT_DRIVER_DIR to point to a different location.



             9955..5566..  RReeggiiss


             The rreeggiiss terminal device generates output in the REGIS
             graphics language.  It has the option of using 4 (the
             default) or 16 colors.

             Syntax:
                   set terminal regis {4 | 16}



             9955..5577..  SSuunn


             The ssuunn terminal driver supports the SunView window sys-
             tem.  It has no options.



             9955..5588..  SSvvgg


             This terminal produces files in the W3C Scalable Vector
             Graphics format.

             Syntax:
                   set terminal svg {size <x>,<y> {|fixed|dynamic}}
                                    {{no}enhanced}
                                    {fname "<font>"} {fsize <fontsize>}
                                    {mouse} {standalone | jsdir
             <dirname>}
                                    {name <plotname>}
                                    {font "<fontname>{,<fontsize>}"}
                                    {fontfile <filename>}
                                    {rounded|butt} {solid|dashed}
             {linewidth <lw>}
                                    {background <rgb_color>}

             where <x> and <y> are the size of the SVG plot to










   GNUPLOT 4.1                                                      343


             generate, ddyynnaammiicc allows a svg-viewer to resize plot,
             whereas the default setting, ffiixxeedd, will request an abso-
             lute size.

             lliinneewwiiddtthh <<ww>> increases the width of all lines used in the
             figure by a factor of <w>.

             <font> is the name of the default font to use (default
             Arial) and <fontsize> is the font size (in points, default
             12). SVG viewing programs may substitute other fonts when
             the file is displayed.

             The svg terminal supports an enhanced text mode, which
             allows font and other formatting commands to be embedded
             in labels and other text strings. The enhanced text mode
             syntax is shared with other gnuplot terminal types. See
             eennhhaanncceedd for more details.

             The mmoouussee option tells gnuplot to add support for mouse
             tracking and for toggling individual plots on/off by
             clicking on the corresponding key entry.  By default this
             is done by including a link that points to a script in a
             local directory, usually /usr/local/share/gnuplot/<ver-
             sion>/js.  You can change this by using the jjssddiirr option
             to specify either a different local directory or a general
             URL. The latter is usually appropriate if you are embed-
             ding the svg into a web page.  Alternatively, the ssttaanndd--
             aalloonnee option embeds the mousing code in the svg document
             itself rather than linking to an external resource.

             When an SVG file will be used in conjunction with external
             files, e.g. if it embeds a PNG image or is referenced by
             javascript code in a web page or embedding document, then
             a unique name is required to avoid potential conflicting
             references to other SVG plots.  Use the nnaammee option to
             ensure uniqueness.

             SVG allows you to embed fonts directly into an SVG docu-
             ment, or to provide a hypertext link to the desired font.
             The ffoonnttffiillee option specifies a local file which is copied
             into the <defs> section of the resulting SVG output file.
             This file may either itself contain a font, or may contain
             the records necessary to create a hypertext reference to
             the desired font. Gnuplot will look for the requested file
             using the directory list in the GNUPLOT_FONTPATH environ-
             mental variable.  NB: You must embed an svg font, not a
             TrueType or PostScript font.
















   GNUPLOT 4.1                                                      344


             9955..5599..  SSvvggaa


             The ssvvggaa terminal driver supports PCs with SVGA graphics.
             It can only be used if it is compiled with DJGPP.  Its
             only option is the font.

             Syntax:
                   set terminal svga {"<fontname>"}



             9955..6600..  TTeekk4400


             This family of terminal drivers supports a variety of VT-
             like terminals.  tteekk4400xxxx supports Tektronix 4010 and oth-
             ers as well as most TEK emulators.  vvtttteekk supports VT-like
             tek40xx terminal emulators.  The following are present
             only if selected when gnuplot is built: kkcc--tteekk4400xxxx sup-
             ports MS-DOS Kermit Tek4010 terminal emulators in color;
             kkmm--tteekk4400xxxx supports them in monochrome. sseellaannaarr supports
             Selanar graphics.  bbiittggrraapphh supports BBN Bitgraph termi-
             nals.  None have any options.



             9955..6611..  TTeekk441100xx


             The tteekk441100xx terminal driver supports the 410x and 420x
             family of Tektronix terminals.  It has no options.



             9955..6622..  TTeexxddrraaww


             The tteexxddrraaww terminal driver supports the LaTeX texdraw
             environment.  It is intended for use with "texdraw.sty"
             and "texdraw.tex" in the texdraw package.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the
             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.

             It has no options.













   GNUPLOT 4.1                                                      345


             9955..6633..  TTggiiff


             Tgif is an X11-based drawing tool---it has nothing to do
             with GIF.

             The ttggiiff driver supports different pointsizes (with sseett
             ppooiinnttssiizzee), different label fonts and font sizes (e.g. sseett
             llaabbeell ""HHaalllloo"" aatt xx,,yy ffoonntt ""HHeellvveettiiccaa,,3344"") and multiple
             graphs on the page.  The proportions of the axes are not
             changed.

             Syntax:
                   set terminal tgif {portrait | landscape | default}
             {<[x,y]>}
                                     {monochrome | color}
                                     {{linewidth | lw} <LW>}
                                     {solid | dashed}
                                     {font "<fontname>{,<fontsize>}"}

             where <[x,y]> specifies the number of graphs in the x and
             y directions on the page, ccoolloorr enables color, lliinneewwiiddtthh
             scales all linewidths by <LW>, "<fontname>" is the name of
             a valid PostScript font, and <fontsize> specifies the size
             of the PostScript font.  ddeeffaauullttss sets all options to
             their defaults: ppoorrttrraaiitt, [[11,,11]], ccoolloorr, lliinnwwiiddtthh 11..00,
             ddaasshheedd, ""HHeellvveettiiccaa,,1188"".

             The ssoolliidd option is usually prefered if lines are colored,
             as they often are in the editor.  Hardcopy will be black-
             and-white, so ddaasshheedd should be chosen for that.

             Multiplot is implemented in two different ways.

             The first multiplot implementation is the standard gnuplot
             multiplot feature:

                   set terminal tgif
                   set output "file.obj"
                   set multiplot
                   set origin x01,y01
                   set size  xs,ys
                   plot ...
                        ...
                   set origin x02,y02
                   plot ...
                   unset multiplot

             See sseett mmuullttiipplloott for further information.

             The second version is the [x,y] option for the driver
             itself.  The advantage of this implementation is that
             everything is scaled and placed automatically without the










   GNUPLOT 4.1                                                      346


             need for setting origins and sizes; the graphs keep their
             natural x/y proportions of 3/2 (or whatever is fixed by
             sseett ssiizzee).

             If both multiplot methods are selected, the standard
             method is chosen and a warning message is given.

             Examples of single plots (or standard multiplot):
                   set terminal tgif                  # defaults
                   set terminal tgif "Times-Roman,24"
                   set terminal tgif landscape
                   set terminal tgif landscape solid

             Examples using the built-in multiplot mechanism:
                   set terminal tgif portrait [2,4]  # portrait; 2
             plots in the x-
                                                     # and 4 in the y-
             direction
                   set terminal tgif [1,2]           # portrait; 1 plot
             in the x-
                                                     # and 2 in the y-
             direction
                   set terminal tgif landscape [3,3] # landscape; 3
             plots in both
                                                     # directions



             9955..6644..  TTiikkzz


             This driver creates output for use with the TikZ package
             of graphics macros in TeX.  It is currently implemented
             via an external lua script, and sseett tteerrmm ttiikkzz is a short
             form of the command sseett tteerrmm lluuaa ttiikkzz.  See tteerrmm lluuaa for
             more information.  Use the command sseett tteerrmm ttiikkzz hheellpp to
             print terminal options.



             9955..6655..  TTkkccaannvvaass


             This terminal driver generates Tk canvas widget commands
             based on Tcl/Tk (default) or Perl.  To use it, rebuild
             ggnnuupplloott (after uncommenting or inserting the appropriate
             line in "term.h"), then

              gnuplot> set term tkcanvas {perltk} {interactive}
              gnuplot> set output 'plot.file'

             After invoking "wish", execute the following sequence of
             Tcl/Tk commands:










   GNUPLOT 4.1                                                      347


              % source plot.file
              % canvas .c
              % pack .c
              % gnuplot .c

             Or, for Perl/Tk use a program like this:

              use Tk;
              my $top = MainWindow->new;
              my $c = $top->Canvas->pack;
              my $gnuplot = do "plot.pl";
              $gnuplot->($c);
              MainLoop;

             The code generated by ggnnuupplloott creates a procedure called
             "gnuplot" that takes the name of a canvas as its argument.
             When the procedure is called, it clears the canvas, finds
             the size of the canvas and draws the plot in it, scaled to
             fit.

             For 2-dimensional plotting (pplloott) two additional proce-
             dures are defined: "gnuplot_plotarea" will return a list
             containing the borders of the plotting area "xleft,
             xright, ytop, ybot" in canvas screen coordinates, while
             the ranges of the two axes "x1min, x1max, y1min, y1max,
             x2min, x2max, y2min, y2max" in plot coordinates can be
             obtained calling "gnuplot_axisranges".  If the "interac-
             tive" option is specified, mouse clicking on a line seg-
             ment will print the coordinates of its midpoint to stdout.
             Advanced actions can happen instead if the user supplies a
             procedure named "user_gnuplot_coordinates", which takes
             the following arguments: "win id x1s y1s x2s y2s x1e y1e
             x2e y2e x1m y1m x2m y2m", the name of the canvas and the
             id of the line segment followed by the coordinates of its
             start and end point in the two possible axis ranges; the
             coordinates of the midpoint are only filled for logarith-
             mic axes.

             The current version of ttkkccaannvvaass supports neither mmuullttiipplloott
             nor rreepplloott.



             9955..6666..  TTppiicc


             The ttppiicc terminal driver supports the LaTeX picture envi-
             ronment with tpic \specials.  It is an alternative to the
             llaatteexx and eeeeppiicc terminal drivers.  Options are the point
             size, line width, and dot-dash interval.

             Syntax:
                   set terminal tpic <pointsize> <linewidth> <interval>










   GNUPLOT 4.1                                                      348


             where ppooiinnttssiizzee and lliinneewwiiddtthh are integers in milli-inches
             and iinntteerrvvaall is a float in inches.  If a non-positive
             value is specified, the default is chosen: pointsize = 40,
             linewidth = 6, interval = 0.1.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally by LaTeX. --- If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             9955..6677..  VVggaaggll


             The vvggaaggll driver is a fast linux console driver with full
             mouse and pm3d support.  It looks at the environment vari-
             able SVGALIB_DEFAULT_MODE for the default mode; if not
             set, it uses a 256 color mode with the highest available
             resolution.

             Syntax:
                set terminal vgagl \
                             background [red] [[green] [blue]] \
                             [uniform | interpolate] \
                             [mode]

             The color mode can also be given with the mode option.
             Both Symbolic names as G1024x768x256 and integers are
             allowed. The bbaacckkggrroouunndd option takes either one or three
             integers in the range [0, 255]. If only one integers is
             supplied, it is taken as gray value for the background.
             If three integers are present, the background gets the
             corresponding color.  The (mutually exclusive) options
             iinntteerrppoollaattee and uunniiffoorrmm control if color interpolation is
             done while drawing triangles (on by default).










   GNUPLOT 4.1                                                      349


             To get high resolution modes, you will probably have to
             modify the configuration file of libvga, usually
             /etc/vga/libvga.conf.  Using the VESA fb is a good choice,
             but this needs to be compiled in the kernel.

             The vgagl driver uses the first *available* vga mode from
             the following list:
              - the driver which was supplied when setting vgagl, e.g.
             `set term vgagl
                G1024x768x256` would first check, if the G1024x768x256
             mode is available.
              - the environment variable SVGALIB_DEFAULT_MODE
              - G1024x768x256
              - G800x600x256
              - G640x480x256
              - G320x200x256
              - G1280x1024x256
              - G1152x864x256
              - G1360x768x256
              - G1600x1200x256




             9955..6688..  VVWWSS


             The VVWWSS terminal driver supports the VAX Windowing System.
             It has no options.  It will sense the display type (mono-
             chrome, gray scale, or color.)  All line styles are plot-
             ted as solid lines.



             9955..6699..  VVxx338844


             The vvxx338844 terminal driver supports the Vectrix 384 and
             Tandy color printers.  It has no options.



             9955..7700..  WWiinnddoowwss


             The wwiinnddoowwss terminal is a fast interactive terminal driver
             that uses the Windows GDI to draw and write text. The
             cross-platform tteerrmmiinnaall wwxxtt is also supported on Windows.

             Syntax:
                   set terminal windows {<n>}
                                        {color | monochrome}
                                        {solid | dashed}










   GNUPLOT 4.1                                                      350


                                        {enhanced | noenhanced}
                                        {font <fontspec>}
                                        {fontscale <scale>}
                                        {linewdith <scale>}
                                        {background <rgb color>}
                                        {title "Plot Window Title"}
                                        {size <width>,<height>}
                                        {position <x>,<y>}
                                        {close}

             Multiple plot windows are supported: sseett tteerrmmiinnaall wwiinn <<nn>>
             directs the output to plot window number n.

             ccoolloorr and mmoonnoocchhrroommee select colored or mono output, ddaasshheedd
             and ssoolliidd select dashed or solid lines. Note that ccoolloorr
             defaults to ssoolliidd, whereas mmoonnoocchhrroommee defaults to ddaasshheedd.
             eennhhaanncceedd enables enhanced text mode features (subscripts,
             superscripts and mixed fonts, see eennhhaanncceedd tteexxtt for more
             information).  <<ffoonnttssppeecc>> is in the format "<font-
             face>,<fontsize>", where "<fontface>" is the name of a
             valid Windows font, and <fontsize> is the size of the font
             in points and both components are optional.  Note that in
             previous versions of gnuplot the ffoonntt statement could be
             left out and <fontsize> could be given as a number without
             double quotes. This is no longer supported.  lliinneewwiiddtthh and
             ffoonnttssccaallee can be used to scale the width of lines and the
             size of text.  ttiittllee changes the title of the graph win-
             dow.  ssiizzee defines the width and height of the window in
             pixel and ppoossiittiioonn the origin of the window i.e. the posi-
             tion of the top left corner on the screen (again in
             pixel). These options override any default settings from
             the wwggnnuupplloott..iinnii file.

             Other options may be changed using the ggrraapphh--mmeennuu or the
             initialization file wwggnnuupplloott..iinnii.

             The Windows version normally terminates immediately as
             soon as the end of any files given as command line argu-
             ments is reached (i.e. in non-interactive mode), unless
             you specify -- as the last command line option.  It will
             also not show the text-window at all, in this mode, only
             the plot.  By giving the optional argument --ppeerrssiisstt (same
             as for gnuplot under x11; former Windows-only options
             //nnooeenndd or --nnooeenndd are still accepted as well), will not
             close gnuplot. Contrary to gnuplot on other operating sys-
             tems, gnuplot's interactive command line is accessible
             after the -persist option.

             The plot window remains open when the gnuplot terminal is
             changed with a sseett tteerrmm command. The plot window can be
             closed with sseett tteerrmm wwiinnddoowwss cclloossee.

             ggnnuupplloott supports different methods to create printed










   GNUPLOT 4.1                                                      351


             output on Windows, see wwiinnddoowwss pprriinnttiinngg. The windows ter-
             minal supports data exchange with other programs via clip-
             board and EMF files, see ggrraapphh--mmeennuu. You can also use the
             tteerrmmiinnaall eemmff to create EMF files.




                  9955..7700..11..  GGrraapphh--mmeennuu


                  The ggnnuupplloott ggrraapphh window has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button(*) or selecting OOppttiioonnss from the system menu:

                  CCooppyy ttoo CClliippbbooaarrdd copies a bitmap and an enhanced
                  Metafile picture.

                  SSaavvee aass EEMMFF...... allows the user to save the current
                  graph window as enhanced metafile

                  PPrriinntt...... prints the graphics windows using a Windows
                  printer driver and allows selection of the printer
                  and scaling of the output.  The output produced by
                  PPrriinntt is not as good as that from ggnnuupplloott's own
                  printer drivers. See also wwiinnddoowwss pprriinnttiinngg.

                  BBrriinngg ttoo TToopp when checked brings the graph window to
                  the top after every plot.

                  CCoolloorr when checked enables color linestyles.  When
                  unchecked it forces monochrome linestyles.

                  DDoouubbllee bbuuffffeerr activates drawing into a memory buffer
                  before copying the graph to the screen. This avoids
                  flickering e.g. during animation and rotation of 3d
                  graphs. See mmoouussee and ssccrroolllliinngg.

                  OOvveerrssaammpplliinngg doubles the size of the virtual canvas.
                  It is scaled down again for drawing to the screen.
                  This gives smoother graphics but requires more memory
                  and computing time. It requires ddoouubbllee bbuuffffeerr.

                  AAnnttiiaalliiaassiinngg selects smoothing of lines and edges.
                  Note that this slows down drawing.

                  BBaacckkggrroouunndd...... sets the window background color.

                  CChhoooossee FFoonntt...... selects the font used in the graphics
                  window.

                  LLiinnee SSttyylleess...... allows customization of the line col-
                  ors and styles.










   GNUPLOT 4.1                                                      352


                  UUppddaattee wwggnnuupplloott..iinnii saves the current window loca-
                  tions, window sizes, text window font, text window
                  font size, graph window font, graph window font size,
                  background color and linestyles to the initialization
                  file wwggnnuupplloott..iinnii.

                  (*) Note that this menu is only available by pressing
                  the right mouse button with uunnsseett mmoouussee.



                  9955..7700..22..  PPrriinnttiinngg


                  In order of preference, graphs may be printed in the
                  following ways:

                  11.. Use the ggnnuupplloott command sseett tteerrmmiinnaall to select a
                  printer and sseett oouuttppuutt to redirect output to a file.

                  22.. Select the PPrriinntt...... command from the ggnnuupplloott ggrraapphh
                  window.  An extra command ssccrreeeenndduummpp does this from
                  the text window.

                  33.. If sseett oouuttppuutt ""PPRRNN"" is used, output will go to a
                  temporary file.  When you exit from ggnnuupplloott or when
                  you change the output with another sseett oouuttppuutt com-
                  mand, a dialog box will appear for you to select a
                  printer port.  If you choose OK, the output will be
                  printed on the selected port, passing unmodified
                  through the print manager.  It is possible to acci-
                  dentally (or deliberately) send printer output meant
                  for one printer to an incompatible printer.




                  9955..7700..33..  TTeexxtt--mmeennuu


                  The ggnnuupplloott tteexxtt window has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button or selecting OOppttiioonnss from the system menu:

                  CCooppyy ttoo CClliippbbooaarrdd copies marked text to the clip-
                  board.

                  PPaassttee copies text from the clipboard as if typed by
                  the user.

                  CChhoooossee FFoonntt...... selects the font used in the text win-
                  dow.











   GNUPLOT 4.1                                                      353


                  SSyysstteemm CCoolloorrss when selected makes the text window
                  honor the System Colors set using the Control Panel.
                  When unselected, text is black or blue on a white
                  background.

                  WWrraapp lloonngg lliinneess when selected lines longer than the
                  current window width are wrapped.

                  UUppddaattee wwggnnuupplloott..iinnii saves the current settings to the
                  initialisation file wwggnnuupplloott..iinnii, which is located in
                  the user's application data directory.




                  9955..7700..44..  WWggnnuupplloott..mmnnuu


                  If the menu file wwggnnuupplloott..mmnnuu is found in the same
                  directory as ggnnuupplloott, then the menu specified in
                  wwggnnuupplloott..mmnnuu will be loaded.  Menu commands:

                   [Menu]      starts a new menu with the name on the
                  following line.
                   [EndMenu]   ends the current menu.
                   [--]        inserts a horizontal menu separator.
                   [|]         inserts a vertical menu separator.
                   [Button]    puts the next macro on a push button
                  instead of a menu.

                  Macros take two lines with the macro name (menu
                  entry) on the first line and the macro on the second
                  line.  Leading spaces are ignored.  Macro commands:

                   [INPUT]     Input string with prompt terminated by
                  [EOS] or {ENTER}
                   [EOS]       End Of String terminator. Generates no
                  output.
                   [OPEN]      Get name of a file to open, with the
                  title of the dialog
                               terminated by [EOS], followed by a
                  default filename terminated
                               by [EOS] or {ENTER}.
                   [SAVE]      Get name of a file to save.  Parameters
                  like [OPEN]
                   [DIRECTORY] Get name of a directory, with the title
                  of the dialog
                               terminated by [EOS] or {ENTER}

                  Macro character substitutions:

                   {ENTER}     Carriage Return '\r'
                   {TAB}       Tab '\011'










   GNUPLOT 4.1                                                      354


                   {ESC}       Escape '\033'
                   {^A}        '\001'
                   ...
                   {^_}        '\031'

                  Macros are limited to 256 characters after expansion.




                  9955..7700..55..  WWggnnuupplloott..iinnii


                  The Windows text window and the wwiinnddoowwss terminal will
                  read some of their options from the [[WWGGNNUUPPLLOOTT]] sec-
                  tion of wwggnnuupplloott..iinnii.  This file is located in the
                  user's application data directory. Here's a sample
                  wwggnnuupplloott..iinnii file:

                        [WGNUPLOT]
                        TextOrigin=0 0
                        TextSize=640 150
                        TextFont=Terminal,9
                        TextWrap=1
                        TextLines=400
                        SysColors=0
                        GraphOrigin=0 150
                        GraphSize=640 330
                        GraphFont=Arial,10
                        GraphColor=1
                        GraphToTop=1
                        GraphDoublebuffer=1
                        GraphOversampling=0
                        GraphAntialiasing=1
                        GraphBackground=255 255 255
                        Border=0 0 0 0 0
                        Axis=192 192 192 2 2
                        Line1=0 0 255 0 0
                        Line2=0 255 0 0 1
                        Line3=255 0 0 0 2
                        Line4=255 0 255 0 3
                        Line5=0 0 128 0 4


                  These settings apply to the wgnuplot text-window
                  only.  The TTeexxttOOrriiggiinn and TTeexxttSSiizzee entries specify
                  the location and size of the text window.

                  The TTeexxttFFoonntt entry specifies the text window font and
                  size.

                  The TTeexxttWWrraapp entry selects wrapping of long text
                  lines.










   GNUPLOT 4.1                                                      355


                  The TTeexxttLLiinneess entry specifies the number of
                  (unwrapped) lines the internal buffer of the text
                  window can hold. This value currently cannot be
                  changed from within wgnuplot.

                  See tteexxtt--mmeennuu.


                  The GGrraapphhFFoonntt entry specifies the font name and size
                  in points.

                  The five numbers given in the BBoorrddeerr, AAxxiiss and LLiinnee
                  entries are the RReedd intensity (0--255), GGrreeeenn inten-
                  sity, BBlluuee intensity, CCoolloorr LLiinneessttyyllee and MMoonnoo
                  LLiinneessttyyllee.  LLiinneessttyylleess are 0=SOLID, 1=DASH, 2=DOT,
                  3=DASHDOT, 4=DASHDOTDOT.  In the sample wwggnnuupplloott..iinnii
                  file above, Line 2 is a green solid line in color
                  mode, or a dashed line in monochrome mode.  The
                  default line width is 1 pixel.  If LLiinneessttyyllee is nega-
                  tive, it specifies the width of a SOLID line in pix-
                  els.  Line1 and any linestyle used with the ppooiinnttss
                  style must be SOLID with unit width.

                  See ggrraapphh--mmeennuu.



             9955..7711..  WWxxtt


             The wwxxtt terminal device generates output in a separate
             window. The window is created by the wxWidgets library,
             where the 'wxt' comes from. The actual drawing is done via
             cairo, a 2D graphics library, and pango, a library for
             laying out and rendering text.

             Syntax:
                     set term wxt {<n>}
                                  {size <width>,<height>} {background
             <rgb_color>}
                                  {{no}enhanced}
                                  {font <font>} {fontscale <scale>}
                                  {title "title"}
                                  {dashed|solid} {dashlength <dl>}
                                  {{no}persist}
                                  {{no}raise}
                                  {{no}ctrl}
                                  {close}

             Multiple plot windows are supported: sseett tteerrmmiinnaall wwxxtt <<nn>>
             directs the output to plot window number n.

             The default window title is based on the window number.










   GNUPLOT 4.1                                                      356


             This title can also be specified with the keyword "title".

             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device.  A plot window can be
             closed by pressing the letter 'q' while that window has
             input focus, by choosing cclloossee from a window manager menu,
             or with sseett tteerrmm wwxxtt <<nn>> cclloossee.

             The size of the plot area is given in pixels, it defaults
             to 640x384.  In addition to that, the actual size of the
             window also includes the space reserved for the toolbar
             and the status bar.  When you resize a window, the plot is
             immediately scaled to fit in the new size of the window.
             Unlike other interactive terminals, the wwxxtt terminal
             scales the whole plot, including fonts and linewidths, and
             keeps its global aspect ratio constant, leaving an empty
             space painted in gray.  If you type rreepplloott, click the
             rreepplloott icon in the terminal toolbar or type a new pplloott
             command, the new plot will completely fit in the window
             and the font size and the linewidths will be reset to
             their defaults.

             The active plot window (the one selected by sseett tteerrmm wwxxtt
             <<nn>>) is interactive. Its behaviour is shared with other
             terminal types. See mmoouussee for details. It also has some
             extra icons, which are supposed to be self-explanatory.

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See eennhhaanncceedd for more
             details.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the wxt terminal will use 'Sans'. Font-
             Size is the font size, in points. If you do not provide
             it, the wxt terminal will use a size of 10 points.
                For example :
                   set term wxt font "Arial,12"
                   set term wxt font "Arial" # to change the font face
             only
                   set term wxt font ",12" # to change the font size
             only
                   set term wxt font "" # to reset the font name and
             size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".










   GNUPLOT 4.1                                                      357


             Pango, the library used to layout the text, is based on
             utf-8. Thus, the wxt terminal has to convert from your
             encoding to utf-8. The default input encoding is based on
             your 'locale'. If you want to use another encoding, make
             sure gnuplot knows which one you are using. See eennccooddiinngg
             for more details.

             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the wxt terminal will use the map provided by
             http://www.unicode.org/ to translate character codes to
             unicode.  Pango will do its best to find a font containing
             this character, looking for your Symbol font, or other
             fonts with a broad unicode coverage, like the DejaVu
             fonts. Note that "the Symbol font" is to be understood as
             the Adobe Symbol font, distributed with Acrobat Reader as
             "SY______.PFB".  Alternatively, the OpenSymbol font, dis-
             tributed with OpenOffice.org as "opens___.ttf", offers the
             same characters. Microsoft has distributed a Symbol font
             ("symbol.ttf"), but it has a different character set with
             several missing or moved mathematic characters. If you
             experience problems with your default setup (if the demo
             enhancedtext.dem is not displayed properly for example),
             you probably have to install one of the Adobe or OpenOf-
             fice Symbol fonts, and remove the Microsoft one.  Other
             non-conform fonts, such as "wingdings" have been observed
             working.

             The rendering of the plot can be altered with a dialog
             available from the toolbar. To obtain the best output pos-
             sible, the rendering involves three mechanisms :
             antialiasing, oversampling and hinting.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).  Hinting avoids
             the blur on horizontal and vertical lines caused by over-
             sampling. The terminal will snap these lines to integer
             coordinates so that a one-pixel-wide line will actually be
             drawn on one and only one pixel.

             By default, the window is raised to the top of your desk-
             top when a plot is drawn. This can be controlled with the
             keyword "raise".  The keyword "persist" will prevent gnu-
             plot from exiting before you explicitely close all the
             plot windows.  Finally, by default the key <space> raises
             the gnuplot console window, and 'q' closes the plot win-
             dow. The keyword "ctrl" allows you to replace those bind-
             ings by <ctrl>+<space> and <ctrl>+'q', respectively.
             These three keywords (raise, persist and ctrl) can also be
             set and remembered between sessions through the configura-
             tion dialog.










   GNUPLOT 4.1                                                      358


             9955..7722..  XX1111



             Syntax:
                set terminal x11 {<n> | window "<string>"}
                                 {title "<string>"}
                                 {{no}enhanced} {font <fontspec>}
                                 {linewidth LW} {solid|dashed}
                                 {{no}persist} {{no}raise} {{no}ctrlq}
                                 {close}
                                 {size XX,YY} {position XX,YY}
                set terminal x11 {reset}

             Multiple plot windows are supported: sseett tteerrmmiinnaall xx1111 <<nn>>
             directs the output to plot window number n.  If n is not
             0, the terminal number will be appended to the window
             title (unless a title has been supplied manually) and the
             icon will be labeled GGnnuupplloott <<nn>>.  The active window may
             be distinguished by a change in cursor (from default to
             crosshair).

             The xx1111 terminal can connect to X windows previously cre-
             ated by an outside application via the option wwiinnddooww fol-
             lowed by a string containing the X ID for the window in
             hexadecimal format.  Gnuplot uses that external X window
             as a container since X does not allow for multiple clients
             selecting the ButtonPress event.  In this way, gnuplot's
             mouse features work within the contained plot window.

                set term x11 window "220001e"

             The x11 terminal supports enhanced text mode (see
             eennhhaanncceedd), subject to the available fonts. In order for
             font size commands embedded in text to have any effect,
             the default x11 font must be scalable. Thus the first
             example below will work as expected, but the second will
             not.

                set term x11 enhanced font "arial,15"
                set title '{/=20 Big} Medium {/=5 Small}'

                set term x11 enhanced font "terminal-14"
                set title '{/=20 Big} Medium {/=5 Small}'

             Plot windows remain open even when the ggnnuupplloott driver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing cclloossee from a window manager
             menu.  All plot windows can be closed by specifying rreesseett,
             which actually terminates the subprocess which maintains
             the windows (unless --ppeerrssiisstt was specified).  The cclloossee
             command can be used to close individual plot windows by










   GNUPLOT 4.1                                                      359


             number.  However, after a rreesseett, those plot windows left
             due to persist cannot be closed with the command cclloossee.  A
             cclloossee without a number closes the current active plot win-
             dow.

             The gnuplot outboard driver, gnuplot_x11, is searched in a
             default place chosen when the program is compiled.  You
             can override that by defining the environment variable
             GNUPLOT_DRIVER_DIR to point to a different location.

             Plot windows will automatically be closed at the end of
             the session unless the --ppeerrssiisstt option was given.

             The options ppeerrssiisstt and rraaiissee are unset by default, which
             means that the defaults (persist == no and raise == yes)
             or the command line options -persist / -raise or the Xre-
             sources are taken.  If [no]persist or [no]raise are speci-
             fied, they will override command line options and Xre-
             sources.  Setting one of these options takes place immedi-
             ately, so the behaviour of an already running driver can
             be modified.  If the window does not get raised, see dis-
             cussion in rraaiissee.

             The option ttiittllee ""<<ttiittllee nnaammee>>"" will supply the title name
             of the window for the current plot window or plot window
             <n> if a number is given.  Where (or if) this title is
             shown depends on your X window manager.

             The size option can be used to set the size of the plot
             window.  The size option will only apply to newly created
             windows.

             The position option can be used to set the position of the
             plot window.  The position option will only apply to newly
             created windows.

             The size or aspect ratio of a plot may be changed by
             resizing the ggnnuupplloott window.

             Linewidths and pointsizes may be changed from within ggnnuu--
             pplloott with sseett lliinneessttyyllee.

             For terminal type xx1111, ggnnuupplloott accepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other ggnnuupplloott options are available for the
             xx1111 terminal.  These may be specified either as command-
             line options when ggnnuupplloott is invoked or as resources in
             the configuration file ".Xdefaults".  They are set upon
             initialization and cannot be altered during a ggnnuupplloott










   GNUPLOT 4.1                                                      360


             session.  (except ppeerrssiisstt and rraaiissee)




                  9955..7722..11..  XX1111__ffoonnttss


                  Upon initial startup, the default font is taken from
                  the X11 resources as set in the system or user .Xde-
                  faults file or on the command line.

                  Example:
                        gnuplot*font: lucidasans-bold-12
                  A new default font may be specified to the x11 driver
                  from inside gnuplot using
                       `set term x11 font "<fontspec>"`
                  The driver first queries the X-server for a font of
                  the exact name given.  If this query fails, then it
                  tries to interpret <fontspec> as
                  "<font>,<size>,<slant>,<weight>" and to construct a
                  full X11 font name of the form
                        -*-<font>-<weight>-<s>-*-*-<size>-*-*-*-*-*-<encod-
                  ing>

                   <font> is the base name of the font (e.g. Times or
                  Symbol)
                   <size> is the point size (defaults to 12 if not
                  specified)
                   <s> is `i` if <slant>=="italic" `o` if
                  <slant>=="oblique" `r` otherwise
                   <weight> is `medium` or `bold` if explicitly
                  requested, otherwise `*`
                   <encoding> is set based on the current character set
                  (see `set encoding`).
                  So sseett tteerrmm xx1111 ffoonntt ""aarriiaall,,1155,,iittaalliicc"" will be trans-
                  lated to -*-arial-*-i-*-*-15-*-*-*-*-*-iso8859-1
                  (assuming default encoding).  The <size>, <slant>,
                  and <weight> specifications are all optional.  If you
                  do not specify <slant> or <weight> then you will get
                  whatever font variant the font server offers first.
                  You may set a default enconding via the corresponding
                  X11 resource. E.g.
                        gnuplot*encoding: iso8859-15
                  The driver also recognizes some common PostScript
                  font names and replaces them with possible X11 or
                  TrueType equivalents.  This same sequence is used to
                  process font requests from sseett llaabbeell.

                  If your gnuplot was built with configuration option
                  --enable-x11-mbfonts, you can specify multi-byte
                  fonts by using the prefix "mbfont:" on the font name.
                  An additional font may be given, separated by a










   GNUPLOT 4.1                                                      361


                  semicolon.  Since multi-byte font encodings are
                  interpreted according to the locale setting, you must
                  make sure that the environmental variable LC_CTYPE is
                  set to some appropriate locale value such as
                  ja_JP.eucJP, ko_KR.EUC, or zh_CN.EUC.

                  Example:
                        set term x11 font 'mbfont:kana14;k14'
                              # 'kana14' and 'k14' are Japanese X11
                  font aliases, and ';'
                              # is the separator of font names.
                        set term x11 font 'mbfont:fixed,16,r,medium'
                              # <font>,<size>,<slant>,<weight> form is
                  also usable.
                        set title '(mb strings)' font 'mbfont:*-fixed-
                  medium-r-normal--14-*'

                  The same syntax applies to the default font in Xre-
                  sources settings, for example,
                        gnuplot*font: \
                            mbfont:-misc-fixed-medium-r-nor-
                  mal--14-*-*-*-c-*-jisx0208.1983-0

                  If gnuplot is built with --enable-x11-mbfonts, you
                  can use two special PostScript font names 'Ryumin-
                  Light-*' and 'GothicBBB-Medium-*' (standard Japanese
                  PS fonts) without the prefix "mbfont:".




                  9955..7722..22..  CCoommmmaanndd--lliinnee__ooppttiioonnss


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting ggnnuupplloott or as resources in your ".Xdefaults"
                  file (note that rraaiissee and ppeerrssiisstt can be overridden
                  later by sseett tteerrmm xx1111 [[nnoo]]rraaiissee [[nnoo]]ppeerrssiisstt)):
























   GNUPLOT 4.1                                                      362


   +-----------------------------------------------------------------------------+
   |  `-mono`      forces monochrome rendering on color displays.                |
   |  `-gray`      requests grayscale rendering on grayscale or color displays.  |
   |               (Grayscale displays receive monochrome rendering by default.) |
   |  `-clear`     requests that the window be cleared momentarily before a      |
   |               new plot is displayed.                                        |
   |  `-tvtwm`     requests that geometry specifications for position of the     |
   |               window be made relative to the currently displayed portion    |
   |               of the virtual root.                                          |
   |  `-raise`     raises plot window after each plot                            |
   | `-noraise`    does not raise plot window after each plot                    |
   |`-novevents`   does not process mouse and key events                         |
   |  `-ctrlq`     closes window on ctrl-q rather than q                         |
   | `-persist`    plot windows survive after main gnuplot program exits         |
   +-----------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.

   Example:
         gnuplot*gray:  on
         gnuplot*ctrlq: on

   ggnnuupplloott also provides a command line option (--ppooiinnttssiizzee <<vv>>) and a
   resource, ggnnuupplloott**ppooiinnttssiizzee:: <<vv>>, to control the size of points
   plotted with the ppooiinnttss plotting style.  The value vv is a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, --ppooiinnttssiizzee 22 uses points twice
   the default size, and --ppooiinnttssiizzee 00..55 uses points half the normal
   size.

   The --nnooeevveennttss switch disables all mouse and key event processing
   (except for qq and <<ssppaaccee>> for closing the window). This is useful
   for programs which use the x11 driver independent of the gnuplot
   main program.

   The --ccttrrllqq switch changes the hot-key that closes a plot window from
   qq to <<ccttrrll>>qq. This is useful is you are using the keystroke-capture
   feature ppaauussee mmoouussee kkeeyyssttrrookkee, since it allows the character qq to be
   captured just as all other alphanumeric characters. The --ccttrrllqq
   switch similarly replaces the <space> hot-key with <ctrl><space> for
   the same reason.




                  9955..7722..33..  MMoonnoocchhrroommee__ooppttiioonnss


                  For monochrome displays, ggnnuupplloott does not honor fore-
                  ground or background colors.  The default is black-










   GNUPLOT 4.1                                                      363


                  on-white.  --rrvv or ggnnuupplloott**rreevveerrsseeVViiddeeoo:: oonn requests
                  white-on-black.




                  9955..7722..44..  CCoolloorr__rreessoouurrcceess


                  The X11 terminal honors the following resources
                  (shown here with their default values) or the
                  greyscale resources.  The values may be color names
                  as listed in the X11 rgb.txt file on your system,
                  hexadecimal RGB color specifications (see X11 docu-
                  mentation), or a color name followed by a comma and
                  an iinntteennssiittyy value from 0 to 1.  For example, bblluuee,,
                  00..55 means a half intensity blue.



                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is simple only for background,
   which maps directly to the usual X11 toolkit option "-bg".  All oth-
   ers can only be set on the command line by use of the generic "-xrm"
   resource override option

   Examples:

         gnuplot -background coral
   to change the background color.

         gnuplot -xrm 'gnuplot*line1Color:blue'
   to override the first linetype color.














   GNUPLOT 4.1                                                      364


                  9955..7722..55..  GGrraayyssccaallee__rreessoouurrcceess


                  When --ggrraayy is selected, ggnnuupplloott honors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.



                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+






                  9955..7722..66..  LLiinnee__rreessoouurrcceess


                  ggnnuupplloott honors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.

























   GNUPLOT 4.1                                                      365


                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   ggnnuupplloott honors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   jjkk (jj and kk are >= 1 and <= 9) means a dashed line with a repeated
   pattern of jj pixels on followed by kk pixels off.  For example, '16'
   is a dotted line with one pixel on followed by six pixels off.  More
   elaborate on/off patterns can be specified with a four-digit value.
   For example, '4441' is four on, four off, four on, one off.  The
   default values shown below are for monochrome displays or monochrome
   rendering on color or grayscale displays.  Color displays default to
   dashed:off



                     +------------------------------+
                     |    gnuplot*dashed: off       |
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+






                  9955..7722..77..  XX1111 ppmm33dd__rreessoouurrcceess


                  Choosing the appropriate visual class and number of
                  colors is a crucial point in X11 applications and a
                  bit awkward, since X11 supports six visual types in










   GNUPLOT 4.1                                                      366


                  different depths.

                  By default ggnnuupplloott uses the default visual of the
                  screen. The number of colors which can be allocated
                  depends on the visual class chosen. On a visual class
                  with a depth > 12bit, gnuplot starts with a maximal
                  number of 0x200 colors.  On a visual class with a
                  depth > 8bit (but <= 12 bit) the maximal number of
                  colors is 0x100, on <= 8bit displays the maximum num-
                  ber of colors is 240 (16 are left for line colors).

                  Gnuplot first starts to allocate the maximal number
                  of colors as stated above.  If this fails, the number
                  of colors is reduced by the factor 2 until gnuplot
                  gets all colors which are requested. If dividing mmaaxx--
                  ccoolloorrss by 2 repeatedly results in a number which is
                  smaller than mmiinnccoolloorrss ggnnuupplloott tries to install a
                  private colormap. In this case the window manager is
                  responsible for swapping colormaps when the pointer
                  is moved in and out the x11 driver's window.

                  The default for mmiinnccoolloorrss is maxcolors / (num_col-
                  ormaps > 1 ? 2 : 8), where num_colormaps is the num-
                  ber of colormaps which are currently used by gnuplot
                  (usually 1, if only one x11 window is open).

                  Some systems support multiple (different) visual
                  classes together on one screen. On these systems it
                  might be necessary to force gnuplot to use a specific
                  visual class, e.g. the default visual might be 8bit
                  PseudoColor but the screen would also support 24bit
                  TrueColor which would be the preferred choice.

                  The information about an Xserver's capabilities can
                  be obtained with the program xxddppyyiinnffoo.  For the
                  visual names below you can choose one of StaticGray,
                  GrayScale, StaticColor, PseudoColor, TrueColor,
                  DirectColor.  If an Xserver supports a requested
                  visual type at different depths, ggnnuupplloott chooses the
                  visual class with the highest depth (deepest).  If
                  the requested visual class matches the default visual
                  and multiple classes of this type are supported, the
                  default visual is preferred.

                  Example: on an 8bit PseudoColor visual you can force
                  a private color map by specifying ggnnuupplloott**mmaaxxccoolloorrss::
                  224400 and ggnnuupplloott**mmiinnccoolloorrss:: 224400.
















   GNUPLOT 4.1                                                      367


                +-----------------------------------------+
                |    gnuplot*maxcolors:  <integer number> |
                |    gnuplot*mincolors:  <integer number> |
                |    gnuplot*visual:     <visual name>    |
                +-----------------------------------------+






                  9955..7722..88..  XX1111 ootthheerr__rreessoouurrcceess


                  By default the contents of the current plot window
                  are exported to the X11 clipboard in response to X
                  events in the window. Setting the resource 'gnu-
                  plot*exportselection' to 'off' or 'false' will dis-
                  able this.

                  By default text rotation is done using a method that
                  is fast, but can corrupt nearby colors depending on
                  the background.  If this is a problem, you can set
                  the resource 'gnuplot.fastrotate' to 'off'




                   +----------------------------------+
                   |    gnuplot*exportselection:  off |
                   |    gnuplot*fastrotate:  on       |
                   |    gnuplot*ctrlq:  off           |
                   +----------------------------------+





             9955..7733..  XXlliibb


             The xxlliibb terminal driver supports the X11 Windows System.
             It generates gnuplot_x11 commands, but sends them to the
             output file specified by sseett oouuttppuutt ''<<ffiilleennaammee>>''. sseett tteerrmm
             xx1111 is equivalent to sseett oouuttppuutt ""||ggnnuupplloott__xx1111 --nnooeevveennttss"";;
             sseett tteerrmm xxlliibb.  xxlliibb takes the same set of options as xx1111.

















   GNUPLOT 4.1                                                      368


             9966..  BBuuggss


             Please e-mail bug reports to the gnuplot-bugs mailing list
             or upload the report to the gnuplot web site on Source-
             Forge.  Please give complete information on the version of
             gnuplot you are using and, if possible, a test script that
             demonstrates the bug.  See sseeeekkiinngg--aassssiissttaannccee.




             9977..  KKnnoowwnn lliimmiittaattiioonnss


             It is not possible to use in-line data (e.g. plot '-' ...)
             inside the curly brackets of a ddoo or wwhhiillee loop.

             The layout and positioning of the plot key is inaccurate
             whenever superscripts, subscripts, or explicit fonts are
             used in the key text.  (Fixed in 4.7)

             Floating point exceptions (floating point number too
             large/small, divide by zero, etc.) may occasionally be
             generated by user defined functions.  Some of the demos in
             particular may cause numbers to exceed the floating point
             range.  Whether the system ignores such exceptions (in
             which case ggnnuupplloott labels the corresponding point as unde-
             fined) or aborts ggnnuupplloott depends on the compiler/runtime
             environment.

             The gamma, bessel, and erf functions do not work for com-
             plex arguments.

             Coordinates specified as "time" wrap at 24 hours.

             The 'nohidden3d' option that is supposed to exempt indi-
             vidual plots from the global property 'set hidden3d' does
             not work for parametric curves.

             X11 terminal: It is difficult to select UTF-8 fonts.  The
             program does not track the true aspect ratio of the x11
             terminal window.  In order for commands such as "set size
             ratio" to work, the x11 window must itself have equal
             height and width.  Only one color palette at a time is
             active for any given x11 plot window.  This means that
             multiplots whose constituent plots use different palettes
             will not display correctly in x11.

             Qt terminal: If the local qt environment does not support
             "opengl" as a rendering mode then display of polygons and
             surfaces can be very slow.











   GNUPLOT 4.1                                                      369


             9988..  EExxtteerrnnaall lliibbrraarriieess


             External library GD (used by PNG/JPEG/GIF drivers): Ver-
             sions of libgd through 2.0.33 contain various bugs in map-
             ping the characters of Adobe's Symbol font.  Also it is
             possible to trigger a library segfault if an anti-aliased
             line crosses an upper corner of the canvas.

             External library PDFlib (used by PDF driver): Gnuplot can
             be linked against libpdf versions 4, 5, or 6. However,
             these versions differ in their handling of piped I/O.
             Therefore gnuplot scripts using piped output to PDF may
             work only for some versions of PDFlib.

             External library svgalib (used by linux and vgagl driver):
             Requires gnuplot to be suid root (bad!) and has many bugs
             that are specific to the video card or graphics driver
             used in X11.

             Internationalization (locale settings): Gnuplot uses the C
             runtime library routine setlocale() to control locale-spe-
             cific formatting of input and output number, times, and
             date strings.  The locales available, and the level of
             support for locale features such as "thousands' grouping
             separator", depend on the internationalization support
             provided by your individual machine.




































   GNUPLOT 4.1                                                        i



                                 TTaabbllee ooff CCoonntteennttss


             Gnuplot  . . . . . . . . . . . . . . . . . . . . . . .   1
             Copyright  . . . . . . . . . . . . . . . . . . . . . .   1
             Introduction . . . . . . . . . . . . . . . . . . . . .   2
             Seeking-assistance . . . . . . . . . . . . . . . . . .   4
             New features . . . . . . . . . . . . . . . . . . . . .   4
             New syntax . . . . . . . . . . . . . . . . . . . . . .   5
             Local customization of linetypes . . . . . . . . . . .   5
             New plot styles  . . . . . . . . . . . . . . . . . . .   5
             Revised polar axes . . . . . . . . . . . . . . . . . .   6
             New smoothing algorithms . . . . . . . . . . . . . . .   6
             New time/date handling . . . . . . . . . . . . . . . .   6
             Statistical summary of data  . . . . . . . . . . . . .   6
             New or revised terminal drivers  . . . . . . . . . . .   6
             Backwards compatibility  . . . . . . . . . . . . . . .   8
             Batch/Interactive Operation  . . . . . . . . . . . . .   8
             Canvas size  . . . . . . . . . . . . . . . . . . . . .   9
             Command-line-editing . . . . . . . . . . . . . . . . .  10
             Comments . . . . . . . . . . . . . . . . . . . . . . .  11
             Coordinates  . . . . . . . . . . . . . . . . . . . . .  11
             Datastrings  . . . . . . . . . . . . . . . . . . . . .  12
             Enhanced text mode . . . . . . . . . . . . . . . . . .  13
             Environment  . . . . . . . . . . . . . . . . . . . . .  14
             Expressions  . . . . . . . . . . . . . . . . . . . . .  15
             Functions  . . . . . . . . . . . . . . . . . . . . . .  16
             Elliptic integrals . . . . . . . . . . . . . . . . . .  19
             Random number generator  . . . . . . . . . . . . . . .  20
             Value  . . . . . . . . . . . . . . . . . . . . . . . .  20
             Operators  . . . . . . . . . . . . . . . . . . . . . .  21
             Unary  . . . . . . . . . . . . . . . . . . . . . . . .  21
             Binary . . . . . . . . . . . . . . . . . . . . . . . .  22
             Ternary  . . . . . . . . . . . . . . . . . . . . . . .  23
             Summation  . . . . . . . . . . . . . . . . . . . . . .  24
             Gnuplot-defined variables  . . . . . . . . . . . . . .  24
             User-defined variables and functions . . . . . . . . .  25
             Fonts  . . . . . . . . . . . . . . . . . . . . . . . .  26
             Cairo (pdfcairo, pngcairo, epscairo, wxt terminals)  .  26
             Gd (png, gif, jpeg terminals)  . . . . . . . . . . . .  27
             Postscript  (also encapsulated postscript *.eps) . . .  27
             Glossary . . . . . . . . . . . . . . . . . . . . . . .  28
             Linetypes, colors, and styles  . . . . . . . . . . . .  29
             Colorspec  . . . . . . . . . . . . . . . . . . . . . .  30
             Background color . . . . . . . . . . . . . . . . . . .  31
             Linecolor variable . . . . . . . . . . . . . . . . . .  32
             Rgbcolor variable  . . . . . . . . . . . . . . . . . .  32
             Linestyles vs linetypes  . . . . . . . . . . . . . . .  33
             Mouse input  . . . . . . . . . . . . . . . . . . . . .  33
             Bind . . . . . . . . . . . . . . . . . . . . . . . . .  34
             Bind space . . . . . . . . . . . . . . . . . . . . . .  35
             Mouse variables  . . . . . . . . . . . . . . . . . . .  36










   GNUPLOT 4.1                                                       ii


             Plotting . . . . . . . . . . . . . . . . . . . . . . .  36
             Start-up (initialization)  . . . . . . . . . . . . . .  37
             String constants and string variables  . . . . . . . .  38
             Substitution and Command line macros . . . . . . . . .  39
             Substitution of system commands in backquotes  . . . .  39
             Substitution of string variables as macros . . . . . .  39
             String variables, macros, and command line substitution . 40
             Syntax . . . . . . . . . . . . . . . . . . . . . . . .  41
             Quote Marks  . . . . . . . . . . . . . . . . . . . . .  42
             Time/Date data . . . . . . . . . . . . . . . . . . . .  43
             Plotting styles  . . . . . . . . . . . . . . . . . . .  44
             Boxerrorbars . . . . . . . . . . . . . . . . . . . . .  45
             Boxes  . . . . . . . . . . . . . . . . . . . . . . . .  45
             Boxplot  . . . . . . . . . . . . . . . . . . . . . . .  47
             Boxxyerrorbars . . . . . . . . . . . . . . . . . . . .  48
             Candlesticks . . . . . . . . . . . . . . . . . . . . .  48
             Circles  . . . . . . . . . . . . . . . . . . . . . . .  49
             Ellipses . . . . . . . . . . . . . . . . . . . . . . .  50
             Dots . . . . . . . . . . . . . . . . . . . . . . . . .  51
             Filledcurves . . . . . . . . . . . . . . . . . . . . .  52
             Financebars  . . . . . . . . . . . . . . . . . . . . .  53
             Fsteps . . . . . . . . . . . . . . . . . . . . . . . .  53
             Fillsteps  . . . . . . . . . . . . . . . . . . . . . .  54
             Histeps  . . . . . . . . . . . . . . . . . . . . . . .  54
             Histograms . . . . . . . . . . . . . . . . . . . . . .  54
             Newhistogram . . . . . . . . . . . . . . . . . . . . .  57
             Automated iteration over multiple columns  . . . . . .  58
             Image  . . . . . . . . . . . . . . . . . . . . . . . .  58
             Transparency . . . . . . . . . . . . . . . . . . . . .  59
             Image failsafe . . . . . . . . . . . . . . . . . . . .  60
             Impulses . . . . . . . . . . . . . . . . . . . . . . .  60
             Labels . . . . . . . . . . . . . . . . . . . . . . . .  60
             Lines  . . . . . . . . . . . . . . . . . . . . . . . .  61
             Linespoints  . . . . . . . . . . . . . . . . . . . . .  61
             Points . . . . . . . . . . . . . . . . . . . . . . . .  62
             Polar  . . . . . . . . . . . . . . . . . . . . . . . .  62
             Steps  . . . . . . . . . . . . . . . . . . . . . . . .  62
             Rgbalpha . . . . . . . . . . . . . . . . . . . . . . .  62
             Rgbimage . . . . . . . . . . . . . . . . . . . . . . .  63
             Vectors  . . . . . . . . . . . . . . . . . . . . . . .  63
             Xerrorbars . . . . . . . . . . . . . . . . . . . . . .  63
             Xyerrorbars  . . . . . . . . . . . . . . . . . . . . .  64
             Yerrorbars . . . . . . . . . . . . . . . . . . . . . .  64
             Xerrorlines  . . . . . . . . . . . . . . . . . . . . .  65
             Xyerrorlines . . . . . . . . . . . . . . . . . . . . .  65
             Yerrorlines  . . . . . . . . . . . . . . . . . . . . .  66
             3D (surface) plots . . . . . . . . . . . . . . . . . .  66
             2D projection (set view map) . . . . . . . . . . . . .  66
             Commands . . . . . . . . . . . . . . . . . . . . . . .  67
             Cd . . . . . . . . . . . . . . . . . . . . . . . . . .  67
             Call . . . . . . . . . . . . . . . . . . . . . . . . .  68
             Clear  . . . . . . . . . . . . . . . . . . . . . . . .  68
             Do . . . . . . . . . . . . . . . . . . . . . . . . . .  69










   =1 .if 0 .tl 'GNUPLOT 4.1''%'


             Evaluate . . . . . . . . . . . . . . . . . . . . . . .  69
             Exit . . . . . . . . . . . . . . . . . . . . . . . . .  70
             Fit  . . . . . . . . . . . . . . . . . . . . . . . . .  70
             Adjustable parameters  . . . . . . . . . . . . . . . .  73
             Short introduction . . . . . . . . . . . . . . . . . .  73
             Error estimates  . . . . . . . . . . . . . . . . . . .  75
             Statistical overview . . . . . . . . . . . . . . . . .  75
             Practical guidelines . . . . . . . . . . . . . . . . .  77
             Control  . . . . . . . . . . . . . . . . . . . . . . .  78
             Control variables  . . . . . . . . . . . . . . . . . .  78
             Environment variables  . . . . . . . . . . . . . . . .  79
             Multi-branch . . . . . . . . . . . . . . . . . . . . .  80
             Starting values  . . . . . . . . . . . . . . . . . . .  80
             Tips . . . . . . . . . . . . . . . . . . . . . . . . .  81
             Help . . . . . . . . . . . . . . . . . . . . . . . . .  82
             History  . . . . . . . . . . . . . . . . . . . . . . .  83
             If . . . . . . . . . . . . . . . . . . . . . . . . . .  83
             If-old . . . . . . . . . . . . . . . . . . . . . . . .  84
             Iteration  . . . . . . . . . . . . . . . . . . . . . .  85
             Load . . . . . . . . . . . . . . . . . . . . . . . . .  85
             Lower  . . . . . . . . . . . . . . . . . . . . . . . .  86
             Pause  . . . . . . . . . . . . . . . . . . . . . . . .  86
             Plot . . . . . . . . . . . . . . . . . . . . . . . . .  88
             Axes . . . . . . . . . . . . . . . . . . . . . . . . .  89
             Binary . . . . . . . . . . . . . . . . . . . . . . . .  89
             General  . . . . . . . . . . . . . . . . . . . . . . .  90
             Array  . . . . . . . . . . . . . . . . . . . . . . . .  91
             Record . . . . . . . . . . . . . . . . . . . . . . . .  92
             Skip . . . . . . . . . . . . . . . . . . . . . . . . .  92
             Format . . . . . . . . . . . . . . . . . . . . . . . .  92
             Endian . . . . . . . . . . . . . . . . . . . . . . . .  93
             Filetype . . . . . . . . . . . . . . . . . . . . . . .  93
             Avs  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Edf  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Png  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Keywords . . . . . . . . . . . . . . . . . . . . . . .  95
             Scan . . . . . . . . . . . . . . . . . . . . . . . . .  95
             Transpose  . . . . . . . . . . . . . . . . . . . . . .  95
             Dx, dy, dz . . . . . . . . . . . . . . . . . . . . . .  96
             Flipx, flipy, flipz  . . . . . . . . . . . . . . . . .  96
             Origin . . . . . . . . . . . . . . . . . . . . . . . .  96
             Center . . . . . . . . . . . . . . . . . . . . . . . .  97
             Rotate . . . . . . . . . . . . . . . . . . . . . . . .  97
             Perpendicular  . . . . . . . . . . . . . . . . . . . .  97
             Data . . . . . . . . . . . . . . . . . . . . . . . . .  98
             Every  . . . . . . . . . . . . . . . . . . . . . . . . 100
             Example datafile . . . . . . . . . . . . . . . . . . . 101
             Index  . . . . . . . . . . . . . . . . . . . . . . . . 102
             Smooth . . . . . . . . . . . . . . . . . . . . . . . . 103
             Acsplines  . . . . . . . . . . . . . . . . . . . . . . 104
             Bezier . . . . . . . . . . . . . . . . . . . . . . . . 105
             Csplines . . . . . . . . . . . . . . . . . . . . . . . 105
             Sbezier  . . . . . . . . . . . . . . . . . . . . . . . 105










   GNUPLOT 4.1                                                       iv


             Unique . . . . . . . . . . . . . . . . . . . . . . . . 105
             Frequency  . . . . . . . . . . . . . . . . . . . . . . 105
             Cumulative . . . . . . . . . . . . . . . . . . . . . . 106
             Cnormal  . . . . . . . . . . . . . . . . . . . . . . . 106
             Kdensity . . . . . . . . . . . . . . . . . . . . . . . 106
             Special-filenames  . . . . . . . . . . . . . . . . . . 107
             Thru . . . . . . . . . . . . . . . . . . . . . . . . . 109
             Using  . . . . . . . . . . . . . . . . . . . . . . . . 110
             Using_examples . . . . . . . . . . . . . . . . . . . . 111
             Pseudocolumns  . . . . . . . . . . . . . . . . . . . . 113
             Xticlabels . . . . . . . . . . . . . . . . . . . . . . 113
             X2ticlabels  . . . . . . . . . . . . . . . . . . . . . 114
             Yticlabels . . . . . . . . . . . . . . . . . . . . . . 114
             Y2ticlabels  . . . . . . . . . . . . . . . . . . . . . 115
             Zticlabels . . . . . . . . . . . . . . . . . . . . . . 115
             Volatile . . . . . . . . . . . . . . . . . . . . . . . 115
             Errorbars  . . . . . . . . . . . . . . . . . . . . . . 115
             Errorlines . . . . . . . . . . . . . . . . . . . . . . 116
             Functions  . . . . . . . . . . . . . . . . . . . . . . 117
             Parametric . . . . . . . . . . . . . . . . . . . . . . 117
             Ranges . . . . . . . . . . . . . . . . . . . . . . . . 118
             Iteration  . . . . . . . . . . . . . . . . . . . . . . 120
             Title  . . . . . . . . . . . . . . . . . . . . . . . . 121
             With . . . . . . . . . . . . . . . . . . . . . . . . . 122
             Print  . . . . . . . . . . . . . . . . . . . . . . . . 125
             Pwd  . . . . . . . . . . . . . . . . . . . . . . . . . 126
             Quit . . . . . . . . . . . . . . . . . . . . . . . . . 126
             Raise  . . . . . . . . . . . . . . . . . . . . . . . . 126
             Refresh  . . . . . . . . . . . . . . . . . . . . . . . 127
             Replot . . . . . . . . . . . . . . . . . . . . . . . . 127
             Reread . . . . . . . . . . . . . . . . . . . . . . . . 128
             Reset  . . . . . . . . . . . . . . . . . . . . . . . . 129
             Save . . . . . . . . . . . . . . . . . . . . . . . . . 129
             Set-show . . . . . . . . . . . . . . . . . . . . . . . 130
             Angles . . . . . . . . . . . . . . . . . . . . . . . . 130
             Arrow  . . . . . . . . . . . . . . . . . . . . . . . . 131
             Autoscale  . . . . . . . . . . . . . . . . . . . . . . 134
             Parametric mode  . . . . . . . . . . . . . . . . . . . 136
             Polar mode . . . . . . . . . . . . . . . . . . . . . . 137
             Bars . . . . . . . . . . . . . . . . . . . . . . . . . 137
             Bind . . . . . . . . . . . . . . . . . . . . . . . . . 137
             Bmargin  . . . . . . . . . . . . . . . . . . . . . . . 138
             Border . . . . . . . . . . . . . . . . . . . . . . . . 138
             Boxwidth . . . . . . . . . . . . . . . . . . . . . . . 140
             Clabel . . . . . . . . . . . . . . . . . . . . . . . . 141
             Clip . . . . . . . . . . . . . . . . . . . . . . . . . 141
             Cntrparam  . . . . . . . . . . . . . . . . . . . . . . 142
             Color box  . . . . . . . . . . . . . . . . . . . . . . 144
             Colornames . . . . . . . . . . . . . . . . . . . . . . 146
             Contour  . . . . . . . . . . . . . . . . . . . . . . . 146
             Data style . . . . . . . . . . . . . . . . . . . . . . 147
             Datafile . . . . . . . . . . . . . . . . . . . . . . . 147
             Set datafile fortran . . . . . . . . . . . . . . . . . 147










   GNUPLOT 4.1                                                        v


             Set datafile nofpe_trap  . . . . . . . . . . . . . . . 148
             Set datafile missing . . . . . . . . . . . . . . . . . 148
             Set datafile separator . . . . . . . . . . . . . . . . 149
             Set datafile commentschars . . . . . . . . . . . . . . 150
             Set datafile binary  . . . . . . . . . . . . . . . . . 150
             Decimalsign  . . . . . . . . . . . . . . . . . . . . . 151
             Dgrid3d  . . . . . . . . . . . . . . . . . . . . . . . 152
             Dummy  . . . . . . . . . . . . . . . . . . . . . . . . 154
             Encoding . . . . . . . . . . . . . . . . . . . . . . . 155
             Fit  . . . . . . . . . . . . . . . . . . . . . . . . . 156
             Fontpath . . . . . . . . . . . . . . . . . . . . . . . 157
             Format . . . . . . . . . . . . . . . . . . . . . . . . 158
             Gprintf  . . . . . . . . . . . . . . . . . . . . . . . 158
             Format specifiers  . . . . . . . . . . . . . . . . . . 159
             Time/date specifiers . . . . . . . . . . . . . . . . . 160
             Function style . . . . . . . . . . . . . . . . . . . . 162
             Functions  . . . . . . . . . . . . . . . . . . . . . . 162
             Grid . . . . . . . . . . . . . . . . . . . . . . . . . 162
             Hidden3d . . . . . . . . . . . . . . . . . . . . . . . 163
             Historysize  . . . . . . . . . . . . . . . . . . . . . 166
             Isosamples . . . . . . . . . . . . . . . . . . . . . . 167
             Key  . . . . . . . . . . . . . . . . . . . . . . . . . 167
             Key placement  . . . . . . . . . . . . . . . . . . . . 171
             Key samples  . . . . . . . . . . . . . . . . . . . . . 172
             Label  . . . . . . . . . . . . . . . . . . . . . . . . 173
             Linetype . . . . . . . . . . . . . . . . . . . . . . . 176
             Lmargin  . . . . . . . . . . . . . . . . . . . . . . . 177
             Loadpath . . . . . . . . . . . . . . . . . . . . . . . 177
             Locale . . . . . . . . . . . . . . . . . . . . . . . . 178
             Logscale . . . . . . . . . . . . . . . . . . . . . . . 178
             Macros . . . . . . . . . . . . . . . . . . . . . . . . 179
             Mapping  . . . . . . . . . . . . . . . . . . . . . . . 179
             Margin . . . . . . . . . . . . . . . . . . . . . . . . 180
             Mouse  . . . . . . . . . . . . . . . . . . . . . . . . 181
             Doubleclick  . . . . . . . . . . . . . . . . . . . . . 183
             Mouseformat  . . . . . . . . . . . . . . . . . . . . . 183
             Scrolling  . . . . . . . . . . . . . . . . . . . . . . 184
             X11 mouse  . . . . . . . . . . . . . . . . . . . . . . 184
             Zoom . . . . . . . . . . . . . . . . . . . . . . . . . 184
             Multiplot  . . . . . . . . . . . . . . . . . . . . . . 185
             Mx2tics  . . . . . . . . . . . . . . . . . . . . . . . 187
             Mxtics . . . . . . . . . . . . . . . . . . . . . . . . 187
             My2tics  . . . . . . . . . . . . . . . . . . . . . . . 188
             Mytics . . . . . . . . . . . . . . . . . . . . . . . . 188
             Mztics . . . . . . . . . . . . . . . . . . . . . . . . 188
             Object . . . . . . . . . . . . . . . . . . . . . . . . 188
             Rectangle  . . . . . . . . . . . . . . . . . . . . . . 189
             Ellipse  . . . . . . . . . . . . . . . . . . . . . . . 190
             Circle . . . . . . . . . . . . . . . . . . . . . . . . 191
             Polygon  . . . . . . . . . . . . . . . . . . . . . . . 192
             Offsets  . . . . . . . . . . . . . . . . . . . . . . . 192
             Origin . . . . . . . . . . . . . . . . . . . . . . . . 193
             Output . . . . . . . . . . . . . . . . . . . . . . . . 193










   GNUPLOT 4.1                                                       vi


             Parametric . . . . . . . . . . . . . . . . . . . . . . 194
             Plot . . . . . . . . . . . . . . . . . . . . . . . . . 195
             Pm3d . . . . . . . . . . . . . . . . . . . . . . . . . 195
             Algorithm  . . . . . . . . . . . . . . . . . . . . . . 196
             Position . . . . . . . . . . . . . . . . . . . . . . . 198
             Scanorder  . . . . . . . . . . . . . . . . . . . . . . 198
             Clipping . . . . . . . . . . . . . . . . . . . . . . . 199
             Color_assignment . . . . . . . . . . . . . . . . . . . 199
             Hidden3d . . . . . . . . . . . . . . . . . . . . . . . 200
             Interpolate  . . . . . . . . . . . . . . . . . . . . . 201
             Deprecated_options . . . . . . . . . . . . . . . . . . 201
             Palette  . . . . . . . . . . . . . . . . . . . . . . . 202
             Rgbformulae  . . . . . . . . . . . . . . . . . . . . . 204
             Defined  . . . . . . . . . . . . . . . . . . . . . . . 205
             Functions  . . . . . . . . . . . . . . . . . . . . . . 207
             Cubehelix  . . . . . . . . . . . . . . . . . . . . . . 207
             File . . . . . . . . . . . . . . . . . . . . . . . . . 208
             Gamma correction . . . . . . . . . . . . . . . . . . . 209
             Postscript . . . . . . . . . . . . . . . . . . . . . . 209
             Pointintervalbox . . . . . . . . . . . . . . . . . . . 210
             Pointsize  . . . . . . . . . . . . . . . . . . . . . . 210
             Polar  . . . . . . . . . . . . . . . . . . . . . . . . 211
             Print  . . . . . . . . . . . . . . . . . . . . . . . . 212
             Psdir  . . . . . . . . . . . . . . . . . . . . . . . . 212
             Raxis  . . . . . . . . . . . . . . . . . . . . . . . . 213
             Rmargin  . . . . . . . . . . . . . . . . . . . . . . . 213
             Rrange . . . . . . . . . . . . . . . . . . . . . . . . 213
             Rtics  . . . . . . . . . . . . . . . . . . . . . . . . 213
             Samples  . . . . . . . . . . . . . . . . . . . . . . . 213
             Size . . . . . . . . . . . . . . . . . . . . . . . . . 214
             Style  . . . . . . . . . . . . . . . . . . . . . . . . 215
             Set style arrow  . . . . . . . . . . . . . . . . . . . 216
             Boxplot  . . . . . . . . . . . . . . . . . . . . . . . 218
             Set style data . . . . . . . . . . . . . . . . . . . . 220
             Set style fill . . . . . . . . . . . . . . . . . . . . 220
             Set style fill transparent . . . . . . . . . . . . . . 221
             Set style function . . . . . . . . . . . . . . . . . . 222
             Set style increment  . . . . . . . . . . . . . . . . . 222
             Set style line . . . . . . . . . . . . . . . . . . . . 223
             Set style circle . . . . . . . . . . . . . . . . . . . 225
             Set style rectangle  . . . . . . . . . . . . . . . . . 225
             Set style ellipse  . . . . . . . . . . . . . . . . . . 226
             Surface  . . . . . . . . . . . . . . . . . . . . . . . 227
             Table  . . . . . . . . . . . . . . . . . . . . . . . . 228
             Terminal . . . . . . . . . . . . . . . . . . . . . . . 228
             Termoption . . . . . . . . . . . . . . . . . . . . . . 229
             Tics . . . . . . . . . . . . . . . . . . . . . . . . . 229
             Ticslevel  . . . . . . . . . . . . . . . . . . . . . . 231
             Ticscale . . . . . . . . . . . . . . . . . . . . . . . 231
             Timestamp  . . . . . . . . . . . . . . . . . . . . . . 231
             Timefmt  . . . . . . . . . . . . . . . . . . . . . . . 232
             Title  . . . . . . . . . . . . . . . . . . . . . . . . 233
             Tmargin  . . . . . . . . . . . . . . . . . . . . . . . 234










   GNUPLOT 4.1                                                      vii


             Trange . . . . . . . . . . . . . . . . . . . . . . . . 234
             Urange . . . . . . . . . . . . . . . . . . . . . . . . 235
             Variables  . . . . . . . . . . . . . . . . . . . . . . 235
             Version  . . . . . . . . . . . . . . . . . . . . . . . 235
             View . . . . . . . . . . . . . . . . . . . . . . . . . 235
             Equal_axes . . . . . . . . . . . . . . . . . . . . . . 236
             Vrange . . . . . . . . . . . . . . . . . . . . . . . . 237
             X2data . . . . . . . . . . . . . . . . . . . . . . . . 237
             X2dtics  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2label  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2mtics  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2range  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2tics . . . . . . . . . . . . . . . . . . . . . . . . 238
             X2zeroaxis . . . . . . . . . . . . . . . . . . . . . . 238
             Xdata  . . . . . . . . . . . . . . . . . . . . . . . . 238
             Xdtics . . . . . . . . . . . . . . . . . . . . . . . . 239
             Xlabel . . . . . . . . . . . . . . . . . . . . . . . . 239
             Xmtics . . . . . . . . . . . . . . . . . . . . . . . . 241
             Xrange . . . . . . . . . . . . . . . . . . . . . . . . 241
             Xtics  . . . . . . . . . . . . . . . . . . . . . . . . 243
             Xtics time_data  . . . . . . . . . . . . . . . . . . . 247
             Xtics rangelimited . . . . . . . . . . . . . . . . . . 247
             Xyplane  . . . . . . . . . . . . . . . . . . . . . . . 248
             Xzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 249
             Y2data . . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2dtics  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2label  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2mtics  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2range  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2tics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Y2zeroaxis . . . . . . . . . . . . . . . . . . . . . . 250
             Ydata  . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ydtics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ylabel . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ymtics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Yrange . . . . . . . . . . . . . . . . . . . . . . . . 251
             Ytics  . . . . . . . . . . . . . . . . . . . . . . . . 251
             Yzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 251
             Zdata  . . . . . . . . . . . . . . . . . . . . . . . . 251
             Zdtics . . . . . . . . . . . . . . . . . . . . . . . . 251
             Zzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 251
             Cbdata . . . . . . . . . . . . . . . . . . . . . . . . 252
             Cbdtics  . . . . . . . . . . . . . . . . . . . . . . . 252
             Zero . . . . . . . . . . . . . . . . . . . . . . . . . 252
             Zeroaxis . . . . . . . . . . . . . . . . . . . . . . . 252
             Zlabel . . . . . . . . . . . . . . . . . . . . . . . . 253
             Zmtics . . . . . . . . . . . . . . . . . . . . . . . . 253
             Zrange . . . . . . . . . . . . . . . . . . . . . . . . 253
             Ztics  . . . . . . . . . . . . . . . . . . . . . . . . 254
             Cblabel  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbmtics  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbrange  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbtics . . . . . . . . . . . . . . . . . . . . . . . . 254










   GNUPLOT 4.1                                                     viii


             Shell  . . . . . . . . . . . . . . . . . . . . . . . . 255
             Splot  . . . . . . . . . . . . . . . . . . . . . . . . 255
             Data-file  . . . . . . . . . . . . . . . . . . . . . . 256
             Matrix . . . . . . . . . . . . . . . . . . . . . . . . 257
             Example datafile . . . . . . . . . . . . . . . . . . . 259
             Grid data  . . . . . . . . . . . . . . . . . . . . . . 260
             Splot surfaces . . . . . . . . . . . . . . . . . . . . 261
             Stats (Statistical Summary)  . . . . . . . . . . . . . 261
             System . . . . . . . . . . . . . . . . . . . . . . . . 263
             Test . . . . . . . . . . . . . . . . . . . . . . . . . 263
             Undefine . . . . . . . . . . . . . . . . . . . . . . . 264
             Unset  . . . . . . . . . . . . . . . . . . . . . . . . 264
             Terminal . . . . . . . . . . . . . . . . . . . . . . . 265
             Update . . . . . . . . . . . . . . . . . . . . . . . . 265
             While  . . . . . . . . . . . . . . . . . . . . . . . . 265
             Terminal types . . . . . . . . . . . . . . . . . . . . 266
             Complete list of terminals . . . . . . . . . . . . . . 266
             Aed767 . . . . . . . . . . . . . . . . . . . . . . . . 266
             Aifm . . . . . . . . . . . . . . . . . . . . . . . . . 266
             Aqua . . . . . . . . . . . . . . . . . . . . . . . . . 267
             Be . . . . . . . . . . . . . . . . . . . . . . . . . . 267
             Command-line_options . . . . . . . . . . . . . . . . . 268
             Monochrome_options . . . . . . . . . . . . . . . . . . 269
             Color_resources  . . . . . . . . . . . . . . . . . . . 269
             Grayscale_resources  . . . . . . . . . . . . . . . . . 270
             Line_resources . . . . . . . . . . . . . . . . . . . . 271
             Cairolatex . . . . . . . . . . . . . . . . . . . . . . 272
             Canvas . . . . . . . . . . . . . . . . . . . . . . . . 275
             Cgi  . . . . . . . . . . . . . . . . . . . . . . . . . 277
             Cgm  . . . . . . . . . . . . . . . . . . . . . . . . . 277
             Cgm font . . . . . . . . . . . . . . . . . . . . . . . 278
             Cgm fontsize . . . . . . . . . . . . . . . . . . . . . 280
             Cgm linewidth  . . . . . . . . . . . . . . . . . . . . 280
             Cgm rotate . . . . . . . . . . . . . . . . . . . . . . 280
             Cgm solid  . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm size . . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm width  . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm nofontlist . . . . . . . . . . . . . . . . . . . . 282
             Context  . . . . . . . . . . . . . . . . . . . . . . . 282
             Requirements . . . . . . . . . . . . . . . . . . . . . 285
             Calling gnuplot from ConTeXt . . . . . . . . . . . . . 285
             Corel  . . . . . . . . . . . . . . . . . . . . . . . . 285
             Debug  . . . . . . . . . . . . . . . . . . . . . . . . 286
             Dumb . . . . . . . . . . . . . . . . . . . . . . . . . 286
             Dxf  . . . . . . . . . . . . . . . . . . . . . . . . . 287
             Dxy800a  . . . . . . . . . . . . . . . . . . . . . . . 287
             Eepic  . . . . . . . . . . . . . . . . . . . . . . . . 287
             Emf  . . . . . . . . . . . . . . . . . . . . . . . . . 289
             Emxvga . . . . . . . . . . . . . . . . . . . . . . . . 290
             Epscairo . . . . . . . . . . . . . . . . . . . . . . . 290
             Epslatex . . . . . . . . . . . . . . . . . . . . . . . 290
             Epson_180dpi . . . . . . . . . . . . . . . . . . . . . 295
             Excl . . . . . . . . . . . . . . . . . . . . . . . . . 296










   GNUPLOT 4.1                                                       ix


             Fig  . . . . . . . . . . . . . . . . . . . . . . . . . 296
             Ggi  . . . . . . . . . . . . . . . . . . . . . . . . . 298
             Gif  . . . . . . . . . . . . . . . . . . . . . . . . . 299
             Examples . . . . . . . . . . . . . . . . . . . . . . . 301
             Gpic . . . . . . . . . . . . . . . . . . . . . . . . . 301
             Grass  . . . . . . . . . . . . . . . . . . . . . . . . 302
             Hp2623a  . . . . . . . . . . . . . . . . . . . . . . . 303
             Hp2648 . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hp500c . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hpgl . . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hpljii . . . . . . . . . . . . . . . . . . . . . . . . 305
             Hppj . . . . . . . . . . . . . . . . . . . . . . . . . 305
             Imagen . . . . . . . . . . . . . . . . . . . . . . . . 305
             Jpeg . . . . . . . . . . . . . . . . . . . . . . . . . 306
             Kyo  . . . . . . . . . . . . . . . . . . . . . . . . . 307
             Latex  . . . . . . . . . . . . . . . . . . . . . . . . 307
             Linux  . . . . . . . . . . . . . . . . . . . . . . . . 308
             Lua  . . . . . . . . . . . . . . . . . . . . . . . . . 308
             Lua tikz . . . . . . . . . . . . . . . . . . . . . . . 309
             Macintosh  . . . . . . . . . . . . . . . . . . . . . . 313
             Mf . . . . . . . . . . . . . . . . . . . . . . . . . . 313
             METAFONT Instructions  . . . . . . . . . . . . . . . . 314
             Mif  . . . . . . . . . . . . . . . . . . . . . . . . . 315
             Mp . . . . . . . . . . . . . . . . . . . . . . . . . . 316
             Metapost Instructions  . . . . . . . . . . . . . . . . 319
             Next . . . . . . . . . . . . . . . . . . . . . . . . . 320
             Openstep (next)  . . . . . . . . . . . . . . . . . . . 321
             Pbm  . . . . . . . . . . . . . . . . . . . . . . . . . 321
             Pdf  . . . . . . . . . . . . . . . . . . . . . . . . . 322
             Pdfcairo . . . . . . . . . . . . . . . . . . . . . . . 323
             Pm . . . . . . . . . . . . . . . . . . . . . . . . . . 325
             Png  . . . . . . . . . . . . . . . . . . . . . . . . . 326
             Examples . . . . . . . . . . . . . . . . . . . . . . . 327
             Pngcairo . . . . . . . . . . . . . . . . . . . . . . . 327
             Postscript . . . . . . . . . . . . . . . . . . . . . . 329
             Editing postscript . . . . . . . . . . . . . . . . . . 333
             Postscript fontfile  . . . . . . . . . . . . . . . . . 333
             Postscript prologue  . . . . . . . . . . . . . . . . . 336
             Postscript adobeglyphnames . . . . . . . . . . . . . . 336
             Pslatex and pstex  . . . . . . . . . . . . . . . . . . 336
             Pstricks . . . . . . . . . . . . . . . . . . . . . . . 339
             Qms  . . . . . . . . . . . . . . . . . . . . . . . . . 340
             Qt . . . . . . . . . . . . . . . . . . . . . . . . . . 340
             Regis  . . . . . . . . . . . . . . . . . . . . . . . . 342
             Sun  . . . . . . . . . . . . . . . . . . . . . . . . . 342
             Svg  . . . . . . . . . . . . . . . . . . . . . . . . . 342
             Svga . . . . . . . . . . . . . . . . . . . . . . . . . 344
             Tek40  . . . . . . . . . . . . . . . . . . . . . . . . 344
             Tek410x  . . . . . . . . . . . . . . . . . . . . . . . 344
             Texdraw  . . . . . . . . . . . . . . . . . . . . . . . 344
             Tgif . . . . . . . . . . . . . . . . . . . . . . . . . 345
             Tikz . . . . . . . . . . . . . . . . . . . . . . . . . 346
             Tkcanvas . . . . . . . . . . . . . . . . . . . . . . . 346










   GNUPLOT 4.1                                                        x


             Tpic . . . . . . . . . . . . . . . . . . . . . . . . . 347
             Vgagl  . . . . . . . . . . . . . . . . . . . . . . . . 348
             VWS  . . . . . . . . . . . . . . . . . . . . . . . . . 349
             Vx384  . . . . . . . . . . . . . . . . . . . . . . . . 349
             Windows  . . . . . . . . . . . . . . . . . . . . . . . 349
             Graph-menu . . . . . . . . . . . . . . . . . . . . . . 351
             Printing . . . . . . . . . . . . . . . . . . . . . . . 352
             Text-menu  . . . . . . . . . . . . . . . . . . . . . . 352
             Wgnuplot.mnu . . . . . . . . . . . . . . . . . . . . . 353
             Wgnuplot.ini . . . . . . . . . . . . . . . . . . . . . 354
             Wxt  . . . . . . . . . . . . . . . . . . . . . . . . . 355
             X11  . . . . . . . . . . . . . . . . . . . . . . . . . 358
             X11_fonts  . . . . . . . . . . . . . . . . . . . . . . 360
             Command-line_options . . . . . . . . . . . . . . . . . 361
             Monochrome_options . . . . . . . . . . . . . . . . . . 362
             Color_resources  . . . . . . . . . . . . . . . . . . . 363
             Grayscale_resources  . . . . . . . . . . . . . . . . . 364
             Line_resources . . . . . . . . . . . . . . . . . . . . 364
             X11 pm3d_resources . . . . . . . . . . . . . . . . . . 365
             X11 other_resources  . . . . . . . . . . . . . . . . . 367
             Xlib . . . . . . . . . . . . . . . . . . . . . . . . . 367
             Bugs . . . . . . . . . . . . . . . . . . . . . . . . . 368
             Known limitations  . . . . . . . . . . . . . . . . . . 368
             External libraries . . . . . . . . . . . . . . . . . . 369



































