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]
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17   Flags:
18       -l  Include category labels in the output
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20       -o  Report zero distance if rasters are overlapping
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22       -q  Run quietly
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24   Parameters:
25       maps=map1,map2
26           Maps for computing inter-class distances
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28       fs=string
29           Output field separator Default: :
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DESCRIPTION

32       Locates the closest points between "objects" in two  raster  maps.   An
33       "object"  is  defined as all the grid cells that have the same category
34       number, and closest means having the shortest "straight-line" distance.
35       The cell centers are considered for the distance calculation (two adja‐
36       cent grid cells have the distance between their cell centers).
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38       The output is an ascii list, one line per pair of objects
39                  cat1:cat2:distance:east1:north1:east2:north2
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42   Explanation:
43       cat1   Category number from map1
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45       cat2   Category number from map2
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47       distance
48              The distance in meters between "cat1" and "cat2"
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50       east1,north1
51              The coordinates of the grid cell  "cat1"  which  is  closest  to
52              "cat2"
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54       east2,north2
55              The  coordinates  of  the  grid  cell "cat2" which is closest to
56              "cat1"
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NOTES

59       The output format lends itself to filtering.   For  example,  to  "see"
60       lines  connecting  each  of  the category pairs in two maps, filter the
61       output using awk and then into d.map graph:
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63       r.distance maps=map1,map2 | \
64       awk -F: '{print "move",$4,$5,"\ndraw",$6,$7}' | d.graph -m
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66       To create a site list of all the "map1" coordinates, filter the  output
67       into awk and then into s.in.ascii:
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69       r.distance maps=map1,map2 | \
70       awk -F: '{print $4,$5}' | s.in.ascii sites=name
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SEE ALSO

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

76       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
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78       Last changed: $Date: 2007/05/28 13:08:50 $
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80       Full index
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84GRASS 6.2.2                                                      r.distance(1)