How to calculate the area of polygon overlap in R?

r overlay polygon intersection
Marc in the box picture Marc in the box · Apr 2, 2012 · Viewed 10.5k times · Source

Does anyone know how to calculate the area in common between 2 or more polygons in R? I would like to have the output of such a calculation be the coordinates of a new polygon for that area of overlap. Cheers

Answer

mdsumner picture mdsumner · Apr 2, 2012

EDIT: these days I would use the 'intersect', 'cover', 'erase', 'union' and related functions in the 'raster' package. They do the hard work to keep the top-level object and attributes.

ORIG: You could use the rgeos package with its gIntersection function. Successive calls between pairs and resulting intersections will get you there. See 

library(rgeos)
?gIntersection

You will need to get into the structure of "SpatialPolygons" in the sp package to get the final coordinates. See the vignette("sp").

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