r.his(1) - f14

1r.his(1)                      Grass User's Manual                     r.his(1)
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NAME

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.
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KEYWORDS

11       raster
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SYNOPSIS

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]  [--verbose]  [--quiet]
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19   Flags:
20       -n
21           Respect NULL values while drawing
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23       --overwrite
24           Allow output files to overwrite existing files
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26       --verbose
27           Verbose module output
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29       --quiet
30           Quiet module output
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32   Parameters:
33       h_map=string
34           Name of layer to be used for HUE
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36       i_map=string
37           Name of layer to be used for INTENSITY
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39       s_map=string
40           Name of layer to be used for SATURATION
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42       r_map=string
43           Name of output layer to be used for RED
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45       g_map=string
46           Name of output layer to be used for GREEN
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48       b_map=string
49           Name of output layer to be used for BLUE
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DESCRIPTION

52       his stands for hue, intensity, and saturation.  This  program  produces
53       red,  green  and  blue  raster map layers providing a visually pleasing
54       combination of hue, intensity, and saturation values from two or  three
55       user-specified raster map layers.
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57       The  human  brain  automatically  interprets  the vast amount of visual
58       information available according to basic rules.  Color, or hue, is used
59       to categorize objects.  Shading, or intensity, is interpreted as three-
60       dimensional texturing. Finally, the degree of haziness, or  saturation,
61       is  associated with distance or depth. This program allows data from up
62       to three raster map layers to be combined into a color  image  (in  the
63       form  of  separate red, green and blue raster map layers) which retains
64       the original information in terms of hue, intensity, and saturation.
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66       While any raster map layer can be used to represent  the  hue  informa‐
67       tion,  map  layers  with  a  few  very distinct colors work best.  Only
68       raster map layers representing continuously varying  data  like  eleva‐
69       tion,  aspect, weights, intensities, or amounts can suitably be used to
70       provide intensity and saturation information.
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72       For example, a visually pleasing image can be made by using a watershed
73       map  for the hue factor, an aspect map for the intensity factor, and an
74       elevation map for saturation. (The user may wish to leave out the  ele‐
75       vation  information  for  a  first  try.)  Ideally, the resulting image
76       should resemble the view from an aircraft looking at  a  terrain  on  a
77       sunny day with a bit of haze in the valleys.
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THE PROCESS

80       Each  map  cell  is processed individually. First, the working color is
81       set to the color of the corresponding cell in the map layer  chosen  to
82       represent  HUE.   Second, this color is multiplied by the red intensity
83       of that cell in the INTENSITY map layer.  This map layer should have an
84       appropriate  gray-scale  color table associated with it. You can ensure
85       this by using the color manipulation capabilities of d.colors or r.col‐
86       ors.   Finally, the color is made somewhat gray-based on the red inten‐
87       sity of that cell in the SATURATION map layer.  Again, this  map  layer
88       should have a gray-scale color table associated with it.
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NOTES

91       The name is misleading. The actual conversion used is
92         <U>H.i.s + <U>G.(1-s)
93       where
94         <U>H   is the R,G,B color from the hue map
95         i   is the red value from the intensity map
96         s   is the red value from the saturation map
97         <U>G   is 50% gray (R = G = B = 0.5)
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100       Either (but not both) of the intensity or the saturation map layers may
101       be omitted. This means that it is possible  to  produce  output  images
102       that represent combinations of his, hi, or hs.  The separate red, green
103       and blue maps can be displayed on the graphics monitor using d.rgb,  or
104       combined  into  a composite RGB layer using r.composite.  Users wishing
105       to simply display an his composite image  without  actually  generating
106       any layers should use the program d.his.
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EXAMPLE

109       Recreate the following d.his command using r.his:
110         r.shaded.relief map=elevation.dem shad=elev.shad_relf
111         d.his h=elevation.dem i=elev.shad_relf brighten=50
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113         r.mapcalc 'elev.shad_relf_bright50 = #elev.shad_relf * 1.5'
114         r.colors elev.shad_relf_bright50 color=grey255
115         r.his   h=elevation.dem   i=elev.shad_relf_bright50  r=esr.r  g=esr.g
116       b=esr.b
117         d.rgb r=esr.r g=esr.g b=esr.b
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AUTHOR

125       Glynn Clements (based upon d.his)
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127       Last changed: $Date: 2007-10-25 14:33:03 +0200 (Thu, 25 Oct 2007) $
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129       Full index
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131       © 2003-2008 GRASS Development Team
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135GRASS 6.3.0                                                           r.his(1)