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



NNAAMMEE
       rr..hhiiss - Produces a color image by combining hue, intensity, and satura-
       tion (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 [--oonn] 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 program produces
       red, green and blue raster map layers  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 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 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),
       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 command line.  In this case, the
       program	will  prompt  the user for parameter values using the standard
       GRASS parser interface.



   FFllaaggss::
       --oo     Overwrite output maps.

       --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.

       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  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.  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
       combined  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_: _$_D_a_t_e_: _2_0_0_2_/_0_6_/_1_6 _1_5_:_2_9_:_1_8 _$



GRASS 5.0							      r.his(1)
