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d.his(1)		    GRASS GIS User's Manual		      d.his(1)

NAME
       d.his   - Displays the result obtained by combining hue,	intensity, and
       saturation (HIS)	values from user-specified input raster	map layers.

KEYWORDS
       display,	graphics, color	transformation,	RGB, HIS, IHS

SYNOPSIS
       d.his
       d.his --help
       d.his   [-n]   hue=string    [intensity=string]	   [saturation=string]
       [brighten=integer]   [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -n
	   Respect NULL	values while drawing

       --help
	   Print usage summary

       --verbose
	   Verbose module output

       --quiet
	   Quiet module	output

       --ui
	   Force launching GUI dialog

   Parameters:
       hue=stringA [required]
	   Name	of layer to be used for	hue

       intensity=string
	   Name	of layer to be used for	intensity

       saturation=string
	   Name	of layer to be used for	saturation

       brighten=integer
	   Percent to brighten intensity channel
	   Options: -99-99
	   Default: 0

DESCRIPTION
       HIS stands for hue, intensity, and saturation.  This program produces a
       raster map layer	providing a visually pleasing combination of hue,  in-
       tensity,	 and saturation	values from two	or three user-specified	raster
       map layers.

       The human brain automatically interprets	the vast amount	of visual  in-
       formation  available  according to basic	rules.	Color, or hue, is used
       to categorize  objects.	 Shading,  or  intensity,  is  interpreted  as
       three-dimensional  texturing. Finally, the degree of haziness, or satu-
       ration, 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 hue, intensity, and	 satu-
       ration.

OPTIONS
       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 (hue), and the name(s) of	map(s)
       containing intensity values (intensity) and/or saturation values	(satu-
       ration).	  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 d.his
       without naming parameter	values on the command line.  In	this case, the
       program will prompt the user for	parameter values  using	 the  standard
       GRASS GUI interface.

       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 hue factor, an aspect map for the intensity factor, and  an
       elevation map for saturation.  (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.

       The brighten option does	not truly represent a percentage, but  calling
       it  that	makes the option easy to understand, and it sounds better than
       Normalized Scaling Factor.

THE PROCESS
       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 hue.  Second, this color is multiplied	by the	red  intensity
       of that cell in the intensity 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	r.colors.  Fi-
       nally, the color	is made	somewhat gray-based on the  red	 intensity  of
       that  cell  in  the saturation map layer.  Again, this map layer	should
       have a gray-scale color table associated	with it.

NOTES
       The name	is misleading. The actual conversion used is
	 H.i.s + G.(1-s)
       where
	 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
	 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 his, hi, or hs.

       Users wishing to	store the result in new	raster map layers  instead  of
       displaying it on	the monitor should use the command r.his.

EXAMPLE
       g.region	raster=elevation
       r.relief	input=elevation	output=elevation_shaded_relief
       d.mon wx0
       d.his hue=elevation intensity=elevation_shaded_relief brighten=50

SEE ALSO
	 d.colortable,	d.frame,  d.rgb,  d.shade, r.colors, r.his, i.his.rgb,
       i.rgb.his

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

SOURCE CODE
       Available at: d.his source code (history)

       Main  index | Display index | Topics index | Keywords index | Graphical
       index | Full index

       A(C) 2003-2021 GRASS Development	Team, GRASS GIS	7.8.6 Reference	Manual

GRASS 7.8.6							      d.his(1)

NAME | KEYWORDS | SYNOPSIS | DESCRIPTION | OPTIONS | THE PROCESS | NOTES | EXAMPLE | SEE ALSO | AUTHOR | SOURCE CODE

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