d.3d(1) 		      Grass User's Manual		       d.3d(1)



NNAAMMEE
       dd..33dd - Displays three-dimensional images based on raster map layers.
       _(_G_R_A_S_S _D_i_s_p_l_a_y _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       dd..33dd
       dd..33dd hheellpp
       dd..33dd [--llaann] mmaapp==_n_a_m_e eelleevvaattiioonn==_n_a_m_e [ffrroomm__ccoooorrddiinnaattee==_x_,_y_,_z] [ttoo__ccoooorrddii--
       nnaattee==_x_,_y_,_z]    [eexxaaggggeerraattiioonn==_v_a_l_u_e]     [lliinneess==_v_a_l_u_e]	 [ffiieelldd==_v_a_l_u_e]
       [ccoolloorr==_n_a_m_e] [bbooxx==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       _d_._3_d  displays  three-dimensional  graphic images based on GRASS raster
       map layers.  The user identifies the viewing point, the line of	sight,
       a  vertical exaggeration factor, the viewing angle (field of view), the
       frequency and color of vector grid lines to appear in the display,  the
       map to be displayed in 3-d, and the map whose category values are to be
       used as elevation values in the 3-dimensional image.


       The program will be run non-interactively if  the  user	specifies  all
       needed  parameter  values and flag settings on the command line. Alter-
       nately, the user can simply type dd..33dd on  the  command  line;  in  this
       case,  the  program  will prompt the user for parameter values and flag
       settings using the standard interface described in the manual entry for
       _p_a_r_s_e_r.


       Three-dimensional images can also be generated through the GRASS _d_._d_i_s_-
       _p_l_a_y program.

OOPPTTIIOONNSS
   FFllaaggss::
       --ll     Display _l_i_n_e_s only, without displaying the raster base _m_a_p.

       --aa     Each grid-cell is rendered using four elevation coordinates: one
	      for  each corner. By default, each corner takes the value of the
	      grid-cell to the lower right. With the -a option each corner  is
	      calculated to be an average of the four bordering cell elevation
	      values.

       --nn     Show null elevations.


   PPaarraammeetteerrss::
       mmaapp==_n_a_m_e
	      The raster map layer used to generate the color shown in the 3-d
	      output  (i.e.,  the  map whose x and y values will be displayed,
	      using the z values present in the _e_l_e_v_a_t_i_o_n map layer.)

       eelleevvaattiioonn==_n_a_m_e
	      The raster map used to generate the texture  in  the  3-d  image
	      (i.e.,  the  map whose category values will become the elevation
	      values in the 3-d map displayed). This need not be an  elevation
	      map layer, although elevation is commonly used.
	      Default: elevation

       ffrroomm__ccoooorrddiinnaattee==_x_,_y_,_z
	      Coordinates  of  the  viewing  point,  given  as: _n_o_r_t_h_i_n_g_,_e_a_s_t_-
	      _i_n_g_,_e_l_e_v_a_t_i_o_n.  The default _f_r_o_m___c_o_o_r_d_i_n_a_t_e value is appropriate
	      for the spearfish sample data set.
	      Default:	Calculated  at	run-time just south-west of the south-
	      west corner.

       ttoo__ccoooorrddiinnaattee==_x_,_y_,_z
	      Coordinates of center of view, given as: _n_o_r_t_h_i_n_g_,_e_a_s_t_i_n_g_,_e_l_e_v_a_-
	      _t_i_o_n.   The  default  _t_o___c_o_o_r_d_i_n_a_t_e value is appropriate for the
	      spearfish sample data set.
	      Default: Calculated at run-time as the center of the image

       eexxaaggggeerraattiioonn==value
	      Vertical exaggeration factor. This value is  multiplied  by  the
	      "elevation" values (category values) in the _e_l_e_v_a_t_i_o_n map layer.
	      As the vertical coordinates are exaggerated, the	elevation  (z)
	      value  of  the  center  of  view	(the  _t_o___c_o_o_r_d_i_n_a_t_e) should be
	      increased.
	      Default: 2.0

       lliinneess==_v_a_l_u_e
	      North-south and east-west trending lines can be drawn on the 3-d
	      image output, to enhance the 3-d effect.	The _l_i_n_e_s value speci-
	      fies the number of rows and columns to skip  between  lines.   0
	      means  "display  no  lines".  Lines  will  be drawn in the _c_o_l_o_r
	      stated.  The user can elect to only display these lines, without
	      displaying the _m_a_p, by setting the -l flag.
	      Default: 1

       ffiieelldd==_v_a_l_u_e
	      The  field  of  view  (viewing  angle)  in  the image, stated in
	      degrees.
	      Default: 30

       ccoolloorr==_n_a_m_e
	      Color of vector _l_i_n_e_s drawn on the output.
	      Options: color, white, red, orange, yellow, green, blue, indigo,
	      violet, gray, black
	      Default: gray

       bbooxx==_n_a_m_e
	      Color of bounding box
	      Options:		   red,orange,yellow,green,blue,indigo,violet,
	      white,black,gray,brown,magenta,aqua,grey,none
	      Default: none



       The resulting three-dimensional image is drawn in the active  frame  on
       the  graphics monitor. The user should select and erase the full graph-
       ics monitor frame before running _d_._3_d to prepare the screen for	graph-
       ics.   Refer to the GRASS program _3_d_._v_i_e_w_._s_h for a demonstration of the
       _d_._3_d program.

IINNTTEERRAACCTTIIVVEE MMOODDEE
       The interactive mode prompts for the raster map	to  be	rendered,  the
       raster  map  to be queried for elevation information, and an optionally
       saved set of saved viewing parameters. The user is then presented  with
       a form in which the options can be modified.


       It  is  suggested  that	the following procedure be used to efficiently
       find the correct viewing  parameters.  Start  with  a  gross  grid  (by
       default,  a  resolution is chosen which limits the total number of rows
       and columns), display lines only, set line  colors  to  "color"	(lines
       take  their  color  from the map), set the box color to something other
       than "none", and use the default viewing coordinates.  Experiment  with
       the  viewing  coordinates  until  the map is positioned in a desireable
       configuration. When the map is lined up correctly, set the display res-
       olution as low as you like for a final image.

BBUUGGSS
       Several	additions  to  this program have been suggested. These include
       the following:

	       Border the image with a visually appealing curtain.

	       Add x,y,z coordinates and scale information  to	the  displayed
	      3-d image.

	       Provide a graphic-oriented user interface for identifying view-
	      ing parameters.

	       Display output more quickly by doing mathematics in integers.

	       Add the option of plotting vector map layers.


SSEEEE AALLSSOO
       _3_d_._v_i_e_w_._s_h_,

       _d_._d_i_s_p_l_a_y_,

       _d_._e_r_a_s_e_,

       _d_._f_r_a_m_e_,

       _p_a_r_s_e_r

AAUUTTHHOORR
       James Westervelt, U.S. Army Construction Engineering  Research  Labora-
       tory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_1_0_/_3_1 _0_8_:_4_0_:_4_7 _$



GRASS 5.0							       d.3d(1)
