i.tape.tm(1)		      Grass User's Manual		  i.tape.tm(1)



NNAAMMEE
       ii..ttaappee..ttmm   - An imagery function that extracts LANDSAT Thematic Mapper
       (TM) imagery from half-inch tape.
       _(_G_R_A_S_S _I_m_a_g_e _P_r_o_c_e_s_s_i_n_g _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       ii..ttaappee..ttmm

DDEESSCCRRIIPPTTIIOONN
       _i_._t_a_p_e_._t_m is a program  that  extracts  LANDSAT	Thematic  Mapper  (TM)
       imagery from half-inch tape.


       This  program must be run in a LOCATION_NAME with a x,y coordinate sys-
       tem (i.e., a coordinate system with projection 0).  For further	infor-
       mation  regarding this LOCATION_NAME refer to the _i_m_a_g_e_r_y manual entry.


       The first prompt in _i_._t_a_p_e_._t_m asks the user for the tape  device  name.
       This  is sometimes  /dev/rmt0 (for a half-inch tape having a density of
       1600 bpi), but this varies with each machine.


       The next prompt is:

       Please mount and load tape, then hit RETURN

       IIMMAAGGEE IIDDEENNTTIIFFIICCAATTIIOONN MMEENNUU


       The first menu in the program asks the user for information  about  the
       data.

	    please enter the following information

       Tape Identification:				__

       Image Description:				__

       Title for the Extracted Raster (Cell) Files:	__

       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)

       This  program  automatically  enters the scene ID number into the field
       for Tape Identification.  The mission, path, row, quadrant,  date,  and
       whether	the image is corrected is automatically entered into the field
       for Image Description.


       The second menu is:

		     THEMATIC MAPPER EXTRACT
       please select the desired tape window (geographic
       region definition) to extract

		    first row: _______(1-2984)
		    last row: _______(1-2984)

		    first col: _______(1-4220)
		    last col: _______(1-4220)


       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)

       The numbers in parentheses are the total number of rows and columns  on
       the  tape  including  zeros  (filler).  This information and additional
       information can also be obtained by running the program _m_._e_x_a_m_i_n_e_._t_a_p_e.
       _m_._e_x_a_m_i_n_e_._t_a_p_e  will read any tape and provide the user with the number
       of files on a tape, the number of records on a  tape,  and  the	record
       lengthes.  Any subset of the image on the tape may be extracted.  For a
       discussion of row and column extraction see the subheading enTITLEd ROW
       AND COLUMN EXTRACTION below.


       The next menu is:

	 please make an x by the bands you want extracted

			     _____ 1
			     _____ 2
			     _____ 3
			     _____ 4
			     _____ 5
			     _____ 6
			     _____ 7

       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)

       TM  imagery has 7 bands, but the user may want to extract only a subset
       of these bands.	See the subheading in this entry enTITLEd ROW AND COL-
       UMN EXTRACTION.


       The  user  then	is asked to enter the prefix/group for the raster band
       files to be created.  This name will precede each band  file  extracted
       into  GRASS.   For  example, if three bands are extracted the following
       three band files will result:


       _p_r_e_f_i_x_n_a_m_e_._1
       _p_r_e_f_i_x_n_a_m_e_._2
       _p_r_e_f_i_x_n_a_m_e_._3


       The specified _p_r_e_f_i_x_n_a_m_e will also automatically become	the  name  for
       the  imagery  group file being created.	Each image or quad (i.e., each
       run of _i_._t_a_p_e_._t_m) should be given a unique prefix/group name.


       The extraction process will begin by first skipping the number of spec-
       ified  files,  advancing  to the first band requested, and then reading
       the tape.  After extracting the requested rows  and  columns  for  each
       band,  the program creates support files for the raster band map layer.
       The percent completion of the extraction is displayed  on  the  screen.
       Because TM imagery is divided into four quads and is stored in multiple
       tape sets, the program is designed to read one quad  at	a  time.   The
       number  of  tapes  required  to store one quad depends on the number of
       bytes per inch in which the data is stored.  If more than one  tape  is
       required  to store one quad, the program will pause and inform the user
       to mount the next tape.


       The extracted band files will be listed as raster map layers  available
       in  the	current  MAPSET  and may be displayed using the GRASS commands
       _d_._d_i_s_p_l_a_y, _d_._r_a_s_t or _i_._p_o_i_n_t_s.

NNOOTTEESS
       After extracting an image from tape the geographic region definition in
       the  x,y  coordinate LOCATION_NAME will be set based upon the extracted
       rows and columns from the tape.	The  relationship  between  the  image
       rows  and  columns and the coordinates of the geographic region is dis-
       cussed in the _i_m_a_g_e_r_y manual entry.


       This program is interactive and requires no command line arguments.

RROOWW AANNDD CCOOLLUUMMNN EEXXTTRRAACCTTIIOONN
       The display options in GRASS allow the user to locate rows and  columns
       on  the	digital image.	If enough disk space is available, one band of
       an entire image or, one band of a portion of an image known to  contain
       the area of interest, can be extracted and displayed.  The _m_e_a_s_u_r_e_m_e_n_t_s
       option in _d_._d_i_s_p_l_a_y, or _d_._w_h_e_r_e (following use of _d_._r_a_s_t) will  echo  x
       and y coordinates to the screen.  (These coordinates will display nega-
       tive numbers in the north-south direction, but  ignoring  the  negative
       sign will yield the row number.)  See the _i_m_a_g_e_r_y manual entry for fur-
       ther explanation.


       Each quad of a TM image contains filler on  both  the  left  and  right
       sides  of  the  quad.  The user may want to identify the row and column
       numbers in order to exclude the filler.	This filler will otherwise  be
       extracted with the image and take up unnecessary disk space.


       If a photograph of the digital image is available, the rows and columns
       to be extracted can be determined from it by  associating  inches  with
       the  total number of known rows and columns in the scene.  For example,
       if the total length of the photograph is 12 inches, the total number of
       rows  on  the  tape  is	2000,  and the northwest corner of the area of
       interest begins 2 inches from the top of the photo, then:  12"  /  2000
       rows = 2" / x rows x = 333.333

       The  northwest  corner  of the area of interest starts at row 333.  The
       starting row, ending row, starting column, and  ending  column  can  be
       calculated in this manner.

SSEEEE AALLSSOO
       _d_._d_i_s_p_l_a_y

       _d_._r_a_s_t

       _d_._w_h_e_r_e

       _i_._g_r_o_u_p

       _i_._p_o_i_n_t_s

       _i_._t_a_p_e_._m_s_s

       _i_._t_a_p_e_._m_s_s_._h

       _i_._t_a_p_e_._o_t_h_e_r

       _i_m_a_g_e_r_y

       _m_._e_x_a_m_i_n_e_._t_a_p_e

AAUUTTHHOORR
       Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_3 _$



GRASS 5.0							  i.tape.tm(1)
