Take a List of SpatialPolygonsDataFrame objects and merge them. This function automates the process of assigning new polygon IDs, which is usually the issue that prevents merging.
APpolyMerge(polyList, newID = FALSE)List. a List of SpatialPolygonsDataFrame objects
logical. If TRUE, the polygon IDs in polyList will be replaced to prevent duplicate IDs.
A merged SpatialPolygonsDataFrame