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

6       r.distance   - Locates the closest points between objects in two raster
7       maps.
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KEYWORDS

10       raster
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SYNOPSIS

13       r.distance
14       r.distance help
15       r.distance [-loq] maps=map1,map2  [fs=string]   [--verbose]  [--quiet]
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17   Flags:
18       -l
19           Include category labels in the output
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21       -o
22           Report zero distance if rasters are overlapping
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24       -q
25           Run quietly
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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       maps=map1,map2
35           Maps for computing inter-class distances
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37       fs=string
38           Output field separator
39           Default: :
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DESCRIPTION

42       Locates the closest points between "objects" in two  raster  maps.   An
43       "object"  is  defined as all the grid cells that have the same category
44       number, and closest means having the shortest "straight-line" distance.
45       The cell centers are considered for the distance calculation (two adja‐
46       cent grid cells have the distance between their cell centers).
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48       The output is an ascii list, one line per pair of objects
49                  cat1:cat2:distance:east1:north1:east2:north2
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51
52   Explanation:
53       cat1
54              Category number from map1
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56       cat2
57              Category number from map2
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59       distance
60              The distance in meters between "cat1" and "cat2"
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62       east1,north1
63              The coordinates of the grid cell  "cat1"  which  is  closest  to
64              "cat2"
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66       east2,north2
67              The  coordinates  of  the  grid  cell "cat2" which is closest to
68              "cat1"
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NOTES

71       The output format lends itself to filtering.   For  example,  to  "see"
72       lines  connecting  each  of  the category pairs in two maps, filter the
73       output using awk and then into d.map graph:
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75       r.distance maps=map1,map2 | \
76       awk -F: '{print "move",$4,$5,"\ndraw",$6,$7}' | d.graph -m
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78       To create a site list of all the "map1" coordinates, filter the  output
79       into awk and then into s.in.ascii:
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81       r.distance maps=map1,map2 | \
82       awk -F: '{print $4,$5}' | s.in.ascii sites=name
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SEE ALSO

85       r.buffer, r.cost, r.drain, v.distance
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AUTHOR

88       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
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90       Last changed: $Date: 2006-10-04 16:32:47 +0200 (Wed, 04 Oct 2006) $
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92       Full index
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94       © 2003-2008 GRASS Development Team
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98GRASS 6.3.0                                                      r.distance(1)