1i.landsat.rgb(1) Grass User's Manual i.landsat.rgb(1)
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6 i.landsat.rgb - Auto-balancing of colors for LANDSAT images
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9 raster, imagery, colors
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12 i.landsat.rgb
13 i.landsat.rgb help
14 i.landsat.rgb [-fpr] red=string green=string blue=string
15 [strength=integer] [--verbose] [--quiet]
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17 Flags:
18 -f
19 Extend colors to full range of data on each channel
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21 -p
22 Preserve relative colors, adjust brightness only
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24 -r
25 Reset to standard color range
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27 --verbose
28 Verbose module output
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30 --quiet
31 Quiet module output
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33 Parameters:
34 red=string
35 LANDSAT red channel
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37 green=string
38 LANDSAT green channel
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40 blue=string
41 LANDSAT blue channel
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43 strength=integer
44 Cropping intensity (upper brightness level)
45 Options: 0-100
46 Default: 98
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49 i.landsat.rgb auto-balances and enhances the color channels of a LAND‐
50 SAT RGB image to provide a more natural color mixture. Only the color
51 table of each image band is modified, the base data remains untouched.
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53 The module works by calculating a histogram for each color channel and
54 removing an adjustable amount of outliers from either end before recal‐
55 ibrating the color scale with r.colors.
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57 It will work with any 8-bit RGB imagery set and the script is easily
58 modified to work with other datasets of greater band-depth.
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61 Depending on the image, it may or may not be advantageous to use the -p
62 flag to preserve the relative color scaling. You will have to experi‐
63 ment with the different options to find a setting that works best for
64 your particular imagery.
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66 The strength option should generally be set in the 90-99 range. The
67 lower the number, the more saturated the image becomes. It represents
68 the percentage cut-off for the top end of the color histogram curve.
69 The lower end is fixed at 2% of the area under the curve.
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71 For quicker execution of this module on large images you can achieve
72 largely similar results by switching to a coarser resolution before the
73 running of the module (using g.region) and then back to the original
74 resolution afterwards.
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78 i.landsat.rgb red=tm.3 green=tm.2 blue=tm.1
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82 The strength option requires further refinement.
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85 d.rgb, g.region, i.oif, r.colors, r.composite, r.univar,
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88 Markus Neteler
89 M. Hamish Bowman, Dept. Marine Science, Otago University, New Zealand
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91 Last changed: $Date: 2006-09-07 11:24:10 +0200 (Thu, 07 Sep 2006) $
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93 Full index
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95 © 2003-2008 GRASS Development Team
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99GRASS 6.3.0 i.landsat.rgb(1)