1r.cross(1) GRASS GIS User's Manual r.cross(1)
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6 r.cross - Creates a cross product of the category values from multiple
7 raster map layers.
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10 raster, statistics
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13 r.cross
14 r.cross --help
15 r.cross [-z] input=string[,string,...] output=name [--overwrite]
16 [--help] [--verbose] [--quiet] [--ui]
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18 Flags:
19 -z
20 Non-NULL data only
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22 --overwrite
23 Allow output files to overwrite existing files
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25 --help
26 Print usage summary
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28 --verbose
29 Verbose module output
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31 --quiet
32 Quiet module output
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34 --ui
35 Force launching GUI dialog
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37 Parameters:
38 input=string[,string,...]Â [required]
39 Names of 2-30 input raster maps
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41 output=name [required]
42 Name for output raster map
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45 r.cross creates an output raster map layer representing all unique com‐
46 binations of category values in the raster input layers
47 (input=name,name,name, ...). At least two, but not more than ten,
48 input map layers must be specified. The user must also specify a name
49 to be assigned to the output raster map layer created by r.cross.
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52 The program will be run non-interactively if the user specifies the
53 names of between 2-10 raster map layers be used as input, and the name
54 of a raster map layer to hold program output.
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56 With the -z flag NULL values are not crossed. This means that if a
57 NULL value occurs in any input data layer, this combination is ignored,
58 even if other data layers contain non-NULL data. In the example given
59 below, use of the -z option would cause 3 categories to be generated
60 instead of 5.
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62 If the -z flag is not specified, then map layer combinations in which
63 some values are NULL will be assigned a unique category value in the
64 resulting output map.
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66 Category values in the new output map layer will be the cross-product
67 of the category values from these existing input map layers.
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70 For example, suppose that, using two raster map layers, the following
71 combinations occur:
72 map1 map2
73 ___________
74 NULL 1
75 NULL 2
76 1 1
77 1 2
78 2 4
79 r.cross would produce a new raster map layer with 5 categories:
80 map1 map2 output
81 ____________________
82 NULL 1 0
83 NULL 2 1
84 1 1 2
85 1 2 3
86 2 4 4
87 Note: The actual category value assigned to a particular combination in
88 the result map layer is dependent on the order in which the combina‐
89 tions occur in the input map layer data and can be considered essen‐
90 tially random. The example given here is illustrative only.
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93 The category file created for the output raster map layer describes the
94 combinations of input map layer category values which generated each
95 category. In the above example, the category labels would be:
96 category category
97 value label
98 ______________________________
99 0 layer1(0) layer2(1)
100 1 layer1(0) layer2(2)
101 2 layer1(1) layer2(1)
102 3 layer1(1) layer2(2)
103 4 layer1(2) layer2(4)
104 A random color table is also generated for the output map layer.
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107 r.covar, r.stats
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110 Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
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113 Available at: r.cross source code (history)
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115 Main index | Raster index | Topics index | Keywords index | Graphical
116 index | Full index
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118 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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122GRASS 7.8.5 r.cross(1)