Crop for SpatialPolygonsDataFrame

Question

I have two SpatialPolygonsDataFrame files: dat1, dat2

extent(dat1)
class       : Extent 
xmin        : -180 
xmax        : 180 
ymin        : -9         


        

Answer 1

You cannot use crop on sp polygon objects. You will need to create a polygon representing the bbox coordinates of dat2 and then can use gIntersects in the rgeos library.

Edit: This comment was in relation to the version available in 2012 and this is no longer the case.