d.rgb(1)

1d.rgb(1)                      Grass User's Manual                     d.rgb(1)
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NAME

6       d.rgb  - Displays three user-specified raster map layers as red, green,
7       and blue overlays in the active graphics frame.
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KEYWORDS

10       display
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SYNOPSIS

13       d.rgb
14       d.rgb help
15       d.rgb [-ox] red=name green=name blue=name
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17   Flags:
18       -o  Overlay (non-null values only)
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20       -x  Don't add to list of commands in monitor
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22   Parameters:
23       red=name
24           Name of raster map to be used for
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26       green=name
27           Name of raster map to be used for
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29       blue=name
30           Name of raster map to be used for
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DESCRIPTION

33       RGB stands for red, green, and blue.  This  program  visually  combines
34       three raster map layers to form a color image. For each layer, the cor‐
35       responding component from the layer's color table is used (e.g. for the
36       red  layer, the red component is used, and so on). In general, the lay‐
37       ers should use a grey-scale color table.
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OPTIONS

40   Flags:
41       -o     Overlay the resulting raster map layer onto whatever is  already
42              displayed in the active graphics frame. Any no-data areas in any
43              of the named raster maps will seem transparent, and  reveal  the
44              underlying  image previously displayed in the graphics frame. If
45              the -o flag is set, only cells containing non-null  values  will
46              be  displayed  from  the  overlaid  raster  map. All other areas
47              (i.e., the portions of the overlaid map that contain  null  val‐
48              ues) will leave the underlying display untouched.
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50   Parameters:
51       red=name
52              Name of raster map layer to be used for RED component.
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54       green=name
55              Name of raster map layer to be used for GREEN component.
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57       blue=name
58              Name of raster map layer to be used for BLUE component.
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NOTES

61       This  is  a  new version of d.rgb, which sends the data to the graphics
62       monitor in true-color RGB format.  Unlike the previous version, it does
63       not  attempt to quantize the combined image into a fixed number of col‐
64       ors.  Nor does it have an option to generate a  composite  layer.   The
65       image  and  raster map layers will not display properly if the graphics
66       device does not have a reasonable sampling of the RGB color-space.
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68       If color quality of satellite image color composites  seems  to  appear
69       poor, run r.colors on the selected satellite channels.
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71       Example: r.info -r image.1
72       min=0
73       max=255
74       r.colors map=image.1 color=rules << EOF
75       0 black
76       255 white
77       EOF
78       r.colors map=image.2 rast=image.1 r.colors map=image.3 rast=image.1
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80       Note: Future GRASS versions may do this for you automatically.
81       To  write out the color composite to a R/G/B raster maps, use r.compos‐
82       ite.
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AUTHOR

94       Glynn Clements
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96       Last changed: $Date: 2005/03/01 20:15:12 $
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98       Full index
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102GRASS 6.2.2                                                           d.rgb(1)