[R-sig-Geo] neighbour patches

[Roger Bivand]

On Sat, 26 Feb 2011, Patrick Giraudoux wrote:

> Hi,
>
> I am tempted to dig in graph theory and analyse connections between discrete 
> landscape patches. Re-reading 'Applied Spatial Data Analysis with R' I was 
> happy to find basics chapter 9. However, it reports on graphs where 
> (euclidian) distance is computed between patch centroids.
>
> Does anybody have an idea about strategies or packages permitting to use the 
> shortest distance between patch borders instead (which is more realistic with 
> regard to animal movement) ?
>

If the patches are Polygons objects in a SpatialPolygons object, the 
gDistance() function in rgeos on R-Forge does this for planar coordinates, 
for example:

gDistance(SP, SP, byid=TRUE)

returns a square distance matrix.

Roger

> Patrick
>
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no