[R-sig-Geo] intersection of two SpatialPolygonsDataFrame

[Barry Rowlingson]

On Wed, Nov 16, 2011 at 3:32 AM, steven wilson <swpt07 at gmail.com> wrote:
> Dear all;
>
> I have been working within R for performing the GIS-like operations
> with shapefiles. My goal is to overlay two spatial polygon data frames
> so I can add info from one of them to the other. I've tried severals
> option such as converting one of them to a spatial polygon object
> (without the associated info) in order to use the 'over' function from
> the maptools library. I have also tried the PBSmapping library and the
> aggregate function from maptools without success so far. Is there any
> way to perform this type of operation in R like in ArcGIS? I would
> appreciate any hint.

 Have you tried the rgeos package? It has (probably) all the spatial
overlay, buffering, merge/union/diff etc operations that you might
ever need!

 What, more precisely, is your problem? I can only guess that you've
got two spatial polygons data frames which have the same geometry but
different attributes, but the polygons are in a different order and
there's no ID variable to link them?

 If the geometries aren't the same then the operation is a bit
trickier since you have to deal with overlaps, and then decide how the
attributes from each layer end up in the result...

Barry