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[,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[,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: r.distance maps=map1,map2 | \
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: r.distance maps=map1,map2 | \
awk -F: '{print $4,$5}' | v.in.ascii format=point output=name fs=space

SEE ALSO¶

r.buffer, r.cost, r.drain, r.grow, r.grow.distance, v.distance

AUTHOR¶

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory Last changed: $Date: 2013-11-16 18:04:46 +0100 (Sat, 16 Nov 2013) $ Full index © 2003-2014 GRASS Development Team