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

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

10       display, graphics, color transformation, RGB, HIS, IHS
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SYNOPSIS

13       d.his
14       d.his --help
15       d.his   [-n]   hue=string    [intensity=string]     [saturation=string]
16       [brighten=integer]   [--help]  [--verbose]  [--quiet]  [--ui]
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18   Flags:
19       -n
20           Respect NULL values while drawing
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22       --help
23           Print usage summary
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25       --verbose
26           Verbose module output
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28       --quiet
29           Quiet module output
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31       --ui
32           Force launching GUI dialog
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34   Parameters:
35       hue=string [required]
36           Name of layer to be used for hue
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38       intensity=string
39           Name of layer to be used for intensity
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41       saturation=string
42           Name of layer to be used for saturation
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44       brighten=integer
45           Percent to brighten intensity channel
46           Options: -99-99
47           Default: 0
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DESCRIPTION

50       HIS stands for hue, intensity, and saturation.  This program produces a
51       raster map layer providing a visually pleasing combination of hue,  in‐
52       tensity,  and saturation values from two or three user-specified raster
53       map layers.
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55       The human brain automatically interprets the vast amount of visual  in‐
56       formation  available  according to basic rules.  Color, or hue, is used
57       to categorize  objects.   Shading,  or  intensity,  is  interpreted  as
58       three-dimensional  texturing. Finally, the degree of haziness, or satu‐
59       ration, is associated with distance or depth. This program allows  data
60       from  up  to three raster map layers to be combined into an image which
61       retains the original information in terms of hue, intensity, and  satu‐
62       ration.
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OPTIONS

65       This  program  can  be run non-interactively or interactively.  It will
66       run non-interactively if the user specifies on  the  command  line  the
67       name  of  a  map containing hue values (hue), and the name(s) of map(s)
68       containing intensity values (intensity) and/or saturation values (satu‐
69       ration).   The  resulting image will be displayed in the active display
70       frame on the graphics monitor.
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72       Alternately, the user can run the program interactively by typing d.his
73       without naming parameter values on the command line.  In this case, the
74       program will prompt the user for parameter values  using  the  standard
75       GRASS GUI interface.
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77       While  any  raster  map layer can be used to represent the hue informa‐
78       tion, map layers with a few  very  distinct  colors  work  best.   Only
79       raster  map  layers  representing continuously varying data like eleva‐
80       tion, aspect, weights, intensities, or amounts can suitably be used  to
81       provide intensity and saturation information.
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83       For example, a visually pleasing image can be made by using a watershed
84       map for the hue factor, an aspect map for the intensity factor, and  an
85       elevation map for saturation.  (The user may wish to leave out the ele‐
86       vation information for a first  try.)   Ideally,  the  resulting  image
87       should  resemble  the  view  from an aircraft looking at a terrain on a
88       sunny day with a bit of haze in the valleys.
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90       The brighten option does not truly represent a percentage, but  calling
91       it  that makes the option easy to understand, and it sounds better than
92       Normalized Scaling Factor.
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THE PROCESS

95       Each map cell is processed individually. First, the  working  color  is
96       set  to  the color of the corresponding cell in the map layer chosen to
97       represent hue.  Second, this color is multiplied by the  red  intensity
98       of that cell in the intensity map layer.  This map layer should have an
99       appropriate gray-scale color table associated with it. You  can  ensure
100       this  by  using  the  color manipulation capabilities of r.colors.  Fi‐
101       nally, the color is made somewhat gray-based on the  red  intensity  of
102       that  cell  in  the saturation map layer.  Again, this map layer should
103       have a gray-scale color table associated with it.
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NOTES

106       The name is misleading. The actual conversion used is
107         H.i.s + G.(1-s)
108       where
109         H   is the R,G,B color from the hue map
110         i   is the red value from the intensity map
111         s   is the red value from the saturation map
112         G   is 50% gray (R = G = B = 0.5)
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114       Either (but not both) of the intensity or the saturation map layers may
115       be  omitted.  This  means  that it is possible to produce output images
116       that represent combinations of his, hi, or hs.
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118       Users wishing to store the result in new raster map layers  instead  of
119       displaying it on the monitor should use the command r.his.
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EXAMPLE

122       g.region raster=elevation
123       r.relief input=elevation output=elevation_shaded_relief
124       d.mon wx0
125       d.his hue=elevation intensity=elevation_shaded_relief brighten=50
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SEE ALSO

128         d.colortable,  d.frame,  d.rgb,  d.shade, r.colors, r.his, i.his.rgb,
129       i.rgb.his
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AUTHOR

132       James Westervelt, U.S. Army Construction Engineering  Research  Labora‐
133       tory
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SOURCE CODE

136       Available at: d.his source code (history)
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138       Accessed: Saturday Jan 21 21:14:07 2023
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140       Main  index | Display index | Topics index | Keywords index | Graphical
141       index | Full index
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143       © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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147GRASS 8.2.1                                                           d.his(1)
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