[R-sig-Geo] Simple and Efficient way to Divide Study Area?
Roger.Bivand at nhh.no
Sun Jun 24 18:26:54 CEST 2007
On Sun, 24 Jun 2007, Kitty Lee wrote:
> Dear R-users,
> I have a study area (with points as observations) and I want to divide the space randomly into sub-regions for further analyses.
> I first generated some random points and then used voronoi to divide the space.
> genxy<-cbind(genx, geny)
> vonout<-voronoi.mosaic(genxy[,1], genxy[,2],
> But there is one major problem with this method--- I wanted to get 20 sub-regions but (in one random run), only 12 enclosed polygons are returned
> My questions are:
> 1) how can I make the unenclosed areas into enclosed polygons? (so that the whole study area is divided into mutually exclusive and exhaustive sub-regions)
> 2) is this a good/efficient method?
Please do note what I wrote in my earlier reply, of 20 June, use deldir
not tripack. Then read the thread referenced from:
for the reamaining questions.
> After getting all enclosed polygons, I have to
> a) turn this into SPatial PolygonDataFrame;
> b) overlay with the existing points;
> c) find out which polygons these point fall into
> d) conduct sub-region analyses
> Is there a more efficient method? How can I efficiently
> a) divide the study area into specified no. of subgroups? (and they don't have to include equal no. of points)
> b) divide the study area into specified no. of subgroups? (each subgroup has the same no. of points)
> Park yourself in front of a world of choices in alternative vehicles.
> [[alternative HTML version deleted]]
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Economic Geography Section, Department of Economics, Norwegian School of
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e-mail: Roger.Bivand at nhh.no
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