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 [--nn] 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 program 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  associated 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 interactively.  It will
       run non-interactively if the user specifies 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 display frame on
       the graphics monitor.


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



   FFllaaggss::
       --nn     Respect NULL values while drawing


   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 SATURATION values.



       While  any  raster  map layer can be used to represent the hue informa-
       tion, map layers with a few  very  distinct  colors  work  best.   Only
       raster  map  layers  representing continuously varying data like eleva-
       tion, 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 ele-
       vation 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 valleys.

TTHHEE PPRROOCCEESSSS
       Each map cell is processed individually. First, the  working  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
       appropriate 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 Labora-
       tory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_6_/_1_6 _1_5_:_2_9_:_1_8 _$



GRASS 5.0							      d.his(1)
