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



NNAAMMEE
       rr..hhiiss  -  Produces  a color image by combining hue, inten-
       sity, and  saturation  (his)  values  from  user-specified
       input raster map layers.
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..hhiiss
       rr..hhiiss hheellpp
       rr..hhiiss [--oo] hh__mmaapp==_n_a_m_e [ii__mmaapp==_n_a_m_e] [ss__mmaapp==_n_a_m_e] rr__mmaapp==_n_a_m_e
       gg__mmaapp==_n_a_m_e bb__mmaapp==_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _h_i_s stands for hue, intensity, and saturation.  This  pro-
       gram  produces  red, green and blue raster map layers pro-
       viding 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 a  color
       image  (in the form of separate red, green and blue raster
       map layers) 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),
       along with the names of the output maps (rr__mmaapp, gg__mmaapp  and
       bb__mmaapp).


       Alternately, the user can run the program interactively by
       typing rr..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.



   FFllaaggss::
       --oo     Overwrite output maps.


   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.

       rr__mmaapp==_n_a_m_e
	      Name of output raster map layer to be used for  RED
	      values.

       gg__mmaapp==_n_a_m_e
	      Name  of	output	raster	map  layer to be used for
	      GREEN values.

       bb__mmaapp==_n_a_m_e
	      Name of output raster map layer to be used for BLUE
	      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 infor-
       mation 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 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.	The separate _r_e_d, _g_r_e_e_n and _b_l_u_e maps can
       be  displayed on the graphics monitor using _d_._r_g_b, or com-
       bined into a composite RGB layer using _i_._c_o_m_p_o_s_i_t_e.  Users
       wishing	to  simply display an _h_i_s composite image without
       actually generating any	layers	should	use  the  program
       _d_._h_i_s.

SSEEEE AALLSSOO
       _d_._h_i_s,  _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,
       _d_._r_g_b,	_i_._c_o_m_p_o_s_i_t_e,   _r_._c_o_l_o_r_s,   _b_l_e_n_d_._s_h,   _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
       Glynn Clements (based upon _d_._h_i_s)

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_4 _$



GRASS 5.0						 r.his(1)
