calculate area between intersecting polygons

Remko Duursma <remkoduursma <at> gmail.com> writes:

Here is a different solution:

library(gpclib)
p1 <- as(poly1, "gpc.poly")
p2 <- as(poly2, "gpc.poly")

area.poly(p2) + area.poly(p1) - area.poly(union(p1,p2))

I.e., take areas of both polygons and subtract the union (check
plot(union(p1,p2)) ) to get the area of the intersection.

greetings,
Remko

Thanks for the hint. I didn't know that the "polygon clipping library" has
been packaged for R, I could have used it several time before. There are
too many package, though this time I admit it would have been easy to hit
upon it by searching CRAN carefully.

Hans Werner

Hans Werner