NAME¶
r.distance - Locates the closest points between objects in two
raster maps.
KEYWORDS¶
raster, distance
SYNOPSIS¶
r.distance
r.distance help
r.distance [-
loq]
maps=
map1,map2
[
fs=
string] [--
verbose] [--
quiet]
Flags:¶
- -l
-
Include category labels in the output
- -o
-
Report zero distance if rasters are overlapping
- -q
-
Run quietly
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- maps=map1,map2
-
Maps for computing inter-class distances
- fs=string
-
Output field separator
Default: :
DESCRIPTION¶
r.distance locates the closest points between "objects" in two
raster maps. An "object" is defined as all the grid cells that have
the same category number, and closest means having the shortest
"straight-line" distance. The cell centers are considered for the
distance calculation (two adjacent grid cells have the distance between their
cell centers).
The output is an ascii list, one line per pair of objects, in the following
form:
cat1:cat2:distance:east1:north1:east2:north2
- cat1
-
Category number from map1
- cat2
-
Category number from map2
- distance
-
The distance in meters between "cat1" and "cat2"
- east1,north1
-
The coordinates of the grid cell "cat1" which is closest to
"cat2"
- east2,north2
-
The coordinates of the grid cell "cat2" which is closest to
"cat1"
Flags¶
-l The -l flag outputs the category labels of the matched raster objects
at the beginning of the line, if they exist.
-o The -o flag reports zero distance if the input rasters are
overlapping.
NOTES¶
The output format lends itself to filtering. For example, to "see"
lines connecting each of the category pairs in two maps, filter the output
using awk and then into
d.graph:
awk -F: '{print "move",$4,$5,"\ndraw",$6,$7}' | d.graph -m
To create a vector map of all the "map1" coordinates, filter the
output into awk and then into
v.in.ascii:
awk -F: '{print $4,$5}' | v.in.ascii format=point output=name fs=space
SEE ALSO¶
r.buffer,
r.cost,
r.drain,
v.distance
AUTHOR¶
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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© 2003-2011 GRASS Development Team
