1r.his(1) Grass User's Manual r.his(1)
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6 r.his - Generates red, green and blue raster map layers combining hue,
7 intensity, and saturation (his) values from user-specified input raster
8 map layers.
9
11 raster
12
14 r.his
15 r.his help
16 r.his [-n] h_map=string [i_map=string] [s_map=string] r_map=string
17 g_map=string b_map=string [--overwrite]
18 Flags:
20 -n Respect NULL values while drawing
21 --overwrite
23 Parameters:
25 h_map=string
26 Name of layer to be used for HUE
27 i_map=string
29 Name of layer to be used for INTENSITY
30 s_map=string
32 Name of layer to be used for SATURATION
33 r_map=string
35 Name of output layer to be used for RED
36 g_map=string
38 Name of output layer to be used for GREEN
39 b_map=string
41 Name of output layer to be used for BLUE
42
44 his stands for hue, intensity, and saturation. This program produces
45 red, green and blue raster map layers providing a visually pleasing
46 combination of hue, intensity, and saturation values from two or three
47 user-specified raster map layers.
48 The human brain automatically interprets the vast amount of visual
50 information available according to basic rules. Color, or hue, is used
51 to categorize objects. Shading, or intensity, is interpreted as three-
52 dimensional texturing. Finally, the degree of haziness, or saturation,
53 is associated with distance or depth. This program allows data from up
54 to three raster map layers to be combined into a color image (in the
55 form of separate red, green and blue raster map layers) which retains
56 the original information in terms of hue, intensity, and saturation.
57 While any raster map layer can be used to represent the hue informa‐
59 tion, map layers with a few very distinct colors work best. Only
60 raster map layers representing continuously varying data like eleva‐
61 tion, aspect, weights, intensities, or amounts can suitably be used to
62 provide intensity and saturation information.
63 For example, a visually pleasing image can be made by using a watershed
65 map for the hue factor, an aspect map for the intensity factor, and an
66 elevation map for saturation. (The user may wish to leave out the ele‐
67 vation information for a first try.) Ideally, the resulting image
68 should resemble the view from an aircraft looking at a terrain on a
69 sunny day with a bit of haze in the valleys.
70
72 Each map cell is processed individually. First, the working color is
73 set to the color of the corresponding cell in the map layer chosen to
74 represent HUE. Second, this color is multiplied by the red intensity
75 of that cell in the INTENSITY map layer. This map layer should have an
76 appropriate gray-scale color table associated with it. You can ensure
77 this by using the color manipulation capabilities of d.colors or r.col‐
78 ors. Finally, the color is made somewhat gray-based on the red inten‐
79 sity of that cell in the SATURATION map layer. Again, this map layer
80 should have a gray-scale color table associated with it.
81
83 The name is misleading. The actual conversion used is
84 <U>H.i.s + <U>G.(1-s)
85 where
86 <U>H is the R,G,B color from the hue map
87 i is the red value from the intensity map
88 s is the red value from the saturation map
89 <U>G is 50% gray (R = G = B = 0.5)
90 Either (but not both) of the intensity or the saturation map layers may
93 be omitted. This means that it is possible to produce output images
94 that represent combinations of his, hi, or hs. The separate red, green
95 and blue maps can be displayed on the graphics monitor using d.rgb, or
96 combined into a composite RGB layer using r.composite. Users wishing
97 to simply display an his composite image without actually generating
98 any layers should use the program d.his.
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101 d.his, d.colors, d.colortable, d.rgb, r.blend, r.colors, r.composite
102 i.his.rgb, i.rgb.his
103
105 Glynn Clements (based upon d.his)
106 Last changed: $Date: 2005/03/01 20:16:31 $
108 Full index
110GRASS 6.2.2 r.his(1)