1v.centroids(1) Grass User's Manual v.centroids(1)
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6 v.centroids - Adds missing centroids to closed boundaries.
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9 vector, centroid, area
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12 v.centroids
13 v.centroids help
14 v.centroids input=name output=name [option=string] [layer=integer]
15 [cat=integer] [step=integer] [--overwrite] [--verbose] [--quiet]
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17 Flags:
18 --overwrite
19 Allow output files to overwrite existing files
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21 --verbose
22 Verbose module output
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24 --quiet
25 Quiet module output
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27 Parameters:
28 input=name
29 Name of input vector map
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31 output=name
32 Name for output vector map
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34 option=string
35 Action to be taken
36 Options: add
37 Default: add
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39 layer=integer
40 Layer number
41 Default: 1
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43 cat=integer
44 Category number starting value
45 Default: 1
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47 step=integer
48 Category increment
49 Default: 1
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52 GRASS defines vector areas as composite entities consisting of a set of
53 closed boundaries and a centroid. The attribute information associated
54 with that area is linked to the centroid. The v.centroids module adds
55 centroids to closed boundaries in the input file and assigns a category
56 number to them. The starting value as well as the increment size may be
57 set using optional parameters.
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59 Multiple attributes may be linked to a single vector entity through
60 numbered fields referred to as layers. Refer to v.category for more
61 details, as v.centroids is simply a frontend to that module.
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63 The boundary itself is often stored without any category reference as
64 it can mark the border between two adjacent areas. Thus it would be
65 ambiguous as to which feature the attribute would belong. In some cases
66 it may, for example, represent a road between two parcels of land. In
67 this case it is entirely appropriate for the boundary to contain cate‐
68 gory information.
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70 (GRASS Shell Script)
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73 v.category
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76 module: M. Hamish Bowman, Dept. Marine Science, Otago University, New
77 Zealand
78 help page: Trevor Wiens
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80 Last changed: $Date: 2006-08-31 13:46:24 +0200 (Thu, 31 Aug 2006) $
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82 Full index
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84 © 2003-2008 GRASS Development Team
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88GRASS 6.3.0 v.centroids(1)