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



NNAAMMEE
       dd..hhiiss  -  Displays the result of combining hue, intensity,
       and saturation  (HIS)  values  from  user-specified  input
       raster map layers.
       _(_G_R_A_S_S _D_i_s_p_l_a_y _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       dd..hhiiss
       dd..hhiiss hheellpp
       dd..hhiiss hh__mmaapp==_n_a_m_e [ii__mmaapp==_n_a_m_e] [ss__mmaapp==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       _h_i_s  stands for hue, intensity, and saturation.	This pro-
       gram produces a raster  map  layer  providing  a  visually
       pleasing  combination  of  hue,	intensity, and saturation
       values from two or three user-specified raster map layers.


       The  human  brain automatically interprets the vast amount
       of visual information available according to basic  rules.
       Color, or _h_u_e, is used to categorize objects.  Shading, or
       _i_n_t_e_n_s_i_t_y, is interpreted as three-dimensional  texturing.
       Finally, the degree of haziness, or _s_a_t_u_r_a_t_i_o_n, is associ-
       ated with distance or depth. This program allows data from
       up to three raster map layers to be combined into an image
       which retains the original information in  terms  of  _h_u_e,
       _i_n_t_e_n_s_i_t_y, and _s_a_t_u_r_a_t_i_o_n.

OOPPTTIIOONNSS
       This  program  can  be  run  non-interactively or interac-
       tively.	It will run non-interactively if the user  speci-
       fies  on the command line the name of a map containing hue
       values (hh__mmaapp),	and  the  name(s)  of  map(s)  containing
       intensity values (ii__mmaapp) and/or saturation values (ss__mmaapp).
       The resulting image will be displayed in the  active  dis-
       play frame on the graphics monitor.


       Alternately, the user can run the program interactively by
       typing dd..hhiiss without naming parameter values on	the  com-
       mand line.  In this case, the program will prompt the user
       for parameter  values  using  the  standard  GRASS  parser
       interface.



   PPaarraammeetteerrss::
       hh__mmaapp==_n_a_m_e
	      Name  of	input raster map layer to be used for HUE
	      values.

       ii__mmaapp==_n_a_m_e
	      Name of input raster  map  layer	to  be	used  for
	      INTENSITY values.

       ss__mmaapp==_n_a_m_e
	      Name of input raster map layer to be used for SATU-
	      RATION values.



       While any raster map layer can be used  to  represent  the
       hue  information, map layers with a few very distinct col-
       ors work best.  Only raster map layers  representing  con-
       tinuously  varying  data  like elevation, aspect, weights,
       intensities, or amounts can suitably be	used  to  provide
       intensity and saturation information.


       For  example,  a  visually  pleasing  image can be made by
       using a watershed map for the _h_u_e factor,  an  aspect  map
       for the _i_n_t_e_n_s_i_t_y factor, and an elevation map for _s_a_t_u_r_a_-
       _t_i_o_n.  (The user may  wish  to  leave  out  the	elevation
       information  for  a  first  try.)   Ideally, the resulting
       image should resemble the view from an aircraft looking at
       a  terrain  on  a sunny day with a bit of haze in the val-
       leys.

TTHHEE PPRROOCCEESSSS
       Each map cell is processed individually. First, the  work-
       ing color is set to the color of the corresponding cell in
       the map layer chosen to represent _H_U_E.  Second, this color
       is  multiplied  by  the	_r_e_d intensity of that cell in the
       _I_N_T_E_N_S_I_T_Y map layer.  This map layer should have an appro-
       priate  gray-scale color table associated with it. You can
       ensure this by using the color  manipulation  capabilities
       of _d_._d_i_s_p_l_a_y, _d_._c_o_l_o_r_s or _r_._c_o_l_o_r_s.  Finally, the color is
       made somewhat gray-based on the _r_e_d intensity of that cell
       in the _S_A_T_U_R_A_T_I_O_N map layer.  Again, this map layer should
       have a gray-scale color table associated with it.

NNOOTTEESS
       The name is misleading. The actual conversion used is

	 <U>H.i.s + <U>G.(1-s)

       where

	 <U>H	is the R,G,B color from the hue map
	 i   is the red value from the intensity map
	 s   is the red value from the saturation map
	 <U>G	is 50% gray (R = G = B = 0.5)




       Either (but not both) of the intensity or  the  saturation
       map  layers may be omitted. This means that it is possible
       to produce output images that  represent  combinations  of
       _h_i_s_,  _h_i_, or _h_s.  Users wishing to store the result in new
       raster map layers instead of displaying it on the  monitor
       should use the program _r_._h_i_s.

SSEEEE AALLSSOO
       _d_._c_o_l_o_r_m_o_d_e,  _d_._c_o_l_o_r_s, _d_._c_o_l_o_r_t_a_b_l_e, _d_._d_i_s_p_l_a_y, _r_._c_o_l_o_r_s,
       _d_._h_i_s,  _i_._h_i_s_._r_g_b,  _i_._r_g_b_._h_i_s,	_h_s_v_._r_g_b_._s_h,   _r_g_b_._h_s_v_._s_h,
       _p_a_r_s_e_r

AAUUTTHHOORR
       James   Westervelt,  U.S.  Army	Construction  Engineering
       Research Laboratory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_2 _$



GRASS 5.0						 d.his(1)
