Ubuntu Manpage: d.his - Displays the result obtained by combining hue, intensity, and saturation (his) values from user-

NAME

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

KEYWORDS

       display, color transformation

SYNOPSIS

       d.his
       d.his help
       d.his [-n] h_map=string  [i_map=string]   [s_map=string]   [brighten=integer]   [--verbose]  [--quiet]

   Flags:
       -n
           Respect NULL values while drawing

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       h_map=string
           Name of layer to be used for HUE

       i_map=string
           Name of layer to be used for INTENSITY

       s_map=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, 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 hue, is used to categorize objects.  Shading, or  intensity,  is  interpreted  as
       three-dimensional  texturing. Finally, the degree of haziness, or saturation, 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 saturation.

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 (h_map), and the name(s) of map(s)
containing intensity values (i_map) and/or saturation values (s_map). 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 information, map layers with a few very
distinct colors work best. Only raster map layers representing continuously 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 hue factor, an aspect
map for the intensity factor, and an elevation map for saturation. (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 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
       d.colors or r.colors.  Finally, 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
         <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 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 program r.his.

EXAMPLE

   Spearfish dataset

         g.region rast=elevation.dem
         r.shaded.relief map=elevation.dem shad=elev.shad_relf
         d.mon x1
         d.his h=elevation.dem i=elev.shad_relf brighten=50

AUTHOR

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

       Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $

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       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                        d.his(1grass)