1r.his(1) GRASS GIS User's Manual r.his(1)
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6 r.his - Generates red, green and blue (RGB) raster map layers combin‐
7 ing hue, intensity and saturation (HIS) values from user-specified
8 input raster map layers.
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11 raster, color transformation, RGB, HIS, IHS
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14 r.his
15 r.his --help
16 r.his [-c] hue=string [intensity=string] [saturation=string]
17 red=string green=string blue=string [bgcolor=name] [--overwrite]
18 [--help] [--verbose] [--quiet] [--ui]
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20 Flags:
21 -c
22 Use colors from color tables for NULL values
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24 --overwrite
25 Allow output files to overwrite existing files
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27 --help
28 Print usage summary
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30 --verbose
31 Verbose module output
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33 --quiet
34 Quiet module output
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36 --ui
37 Force launching GUI dialog
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39 Parameters:
40 hue=string [required]
41 Name of layer to be used for hue
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43 intensity=string
44 Name of layer to be used for intensity
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46 saturation=string
47 Name of layer to be used for saturation
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49 red=string [required]
50 Name of output layer to be used for red
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52 green=string [required]
53 Name of output layer to be used for green
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55 blue=string [required]
56 Name of output layer to be used for blue
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58 bgcolor=name
59 Color to use instead of NULL values
60 Either a standard color name, R:G:B triplet, or "none"
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63 HIS stands for hue, intensity, and saturation. This program produces
64 red, green and blue raster map layers providing a visually pleasing
65 combination of hue, intensity, and saturation values from two or three
66 user-specified raster map layers.
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68 The human brain automatically interprets the vast amount of visual
69 information available according to basic rules. Color, or hue, is used
70 to categorize objects. Shading, or intensity, is interpreted as
71 three-dimensional texturing. Finally, the degree of haziness, or satu‐
72 ration, is associated with distance or depth. This program allows data
73 from up to three raster map layers to be combined into a color image
74 (in the form of separate red, green and blue raster map layers) which
75 retains the original information in terms of hue, intensity, and satu‐
76 ration.
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78 While any raster map layer can be used to represent the hue informa‐
79 tion, map layers with a few very distinct colors work best. Only
80 raster map layers representing continuously varying data like eleva‐
81 tion, aspect, weights, intensities, or amounts can suitably be used to
82 provide intensity and saturation information.
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84 For example, a visually pleasing image can be made by using a watershed
85 map for the hue factor, an aspect map for the intensity factor, and an
86 elevation map for saturation. (The user may wish to leave out the ele‐
87 vation information for a first try.) Ideally, the resulting image
88 should resemble the view from an aircraft looking at a terrain on a
89 sunny day with a bit of haze in the valleys.
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91 The Process
92 Each map cell is processed individually. First, the working color is
93 set to the color of the corresponding cell in the map layer chosen to
94 represent hue. Second, this color is multiplied by the red intensity
95 of that cell in the intensity map layer. This map layer should have an
96 appropriate gray-scale color table associated with it. You can ensure
97 this by using the color manipulation capabilities of r.colors.
98 Finally, the color is made somewhat gray-based on the red intensity of
99 that cell in the saturation map layer. Again, this map layer should
100 have a gray-scale color table associated with it.
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103 The name is misleading. The actual conversion used is
104 H.i.s + G.(1-s)
105 where
106 H is the R,G,B color from the hue map
107 i is the red value from the intensity map
108 s is the red value from the saturation map
109 G is 50% gray (R = G = B = 0.5)
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111 Either (but not both) of the intensity or the saturation map layers may
112 be omitted. This means that it is possible to produce output images
113 that represent combinations of his, hi, or hs. The separate red, green
114 and blue maps can be displayed on the graphics monitor using d.rgb, or
115 combined into a composite RGB layer using r.composite. Users wishing
116 to simply display an his composite image without actually generating
117 any layers should use the program d.his.
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120 Recreate the following example for d.his using r.his. First, create
121 shaded relief and show it.
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
126 Second, compute lighter version of color of shaded relief. Then con‐
127 vert from HIS model to RGB and show the result.
128 r.mapcalc "elevation_shaded_relief_bright_50 = #elevation_shaded_relief * 1.5"
129 r.colors elevation_shaded_relief_bright_50 color=grey255
130 r.his hue=elevation intensity=elevation_shaded_relief_bright_50 \
131 red=shadedmap_r green=shadedmap_g blue=shadedmap_b
132 d.mon wx1
133 d.rgb red=shadedmap_r green=shadedmap_g blue=shadedmap_b
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136 d.his, d.colortable, d.rgb, r.blend, r.colors, r.composite, r.mapcalc,
137 r.shade, i.his.rgb, i.rgb.his
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140 Glynn Clements (based upon d.his)
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143 Available at: r.his source code (history)
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145 Main index | Raster index | Topics index | Keywords index | Graphical
146 index | Full index
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148 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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152GRASS 7.8.5 r.his(1)