Re: R-sig-Geo Digest, Vol 69, Issue 3

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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 02 May 2009 22:52:36 -0500
> From: Jim Burke <j.burke <at> earthlink.net>
> Subject: [R-sig-Geo] How can I convert a "SpatialPolygons" object to a
> 	"polylist"?
> To: r-sig-geo <at> stat.math.ethz.ch
> Message-ID: <49FD1504.7060101 <at> earthlink.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> How can I convert a "SpatialPolygons" object to a "polylist" 
>
> I have a file read in with "readShapePoly". This contains the polygon
> long lats in a slot called "coords". I want to use the package "splancs"
> "inout" function which works according to the doc with polygon data sets.
> An example Map2Poly which works with "inout" lists itself as a class 
> "polylist".  
>
> Thanks,
> Jim Burke

if your SpatialPolygons name is e.g. myObject

lapply(myObject <at> polygons, function(x) x <at> Polygons[[1]] <at> coords)

should make it in the very simple case (the most common too anyway) 
where each attribute line corresponds to one single polygon. It will 
provide you with a list whose elements will be the coordinates of each 
polygon.

More complex cases are a bit more difficult to handle

Patrick