[R] Identify points that lie within polygon

[Ally]

I have a complex 2D polygon with thousands of vertices, and I'd like to be
able to identify points from a large set contained within the polygon, and
was wondering if there might be an efficient way of doing this?  Any advice
would be useful!  Here is a small example of what I mean:

# make polygon
v1<-c(0,1,1,2,1,3,6,7)
v2<-c(1,3,3,5,6,7,8,9)
plot(v1, v2, type = "n" )
polygon(v1, v2, lwd = 2, col = "red")

# plot a set of candidate grid points
grid<-seq(0, 10, length.out = 30)
pts<-expand.grid(grid, grid)
points(pts, pch = 19, col = 1, cex = 1)

Many thanks!

Alastair




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