[R-sig-Geo] how to dismiss points outside of my area of interest in a raster

[Robert J. Hijmans]

Manuel,

library(raster)
# Assuming you have matrix of points (or SpatialPoints*)
pt <- (cbind(runif(100), runif(100)) -0.5) * 500
spt <- SpatialPoints(pt)
# and a RasterLayer
r <- raster()

# you can do

e <- polygonFromExtent(r)
o <- overlay(e, spt)
o <- which(!is.na(o))
pts <- pt[o,]


# show that it worked
plot(pt)
r[] = 1
plot(r, add=TRUE, legend=FALSE)
points(pt, col='blue')
points(pts, col='red', pch=20)


Robert

On Thu, Nov 4, 2010 at 5:43 AM, Manuel Spínola <mspinola10 at gmail.com> wrote:
> Dear list members,
>
> How can eliminate or dismiss points that do not "touch" my raster file?
> This mean those points that are outside of the raster area.
> When I have my plot of the rester and I draw the points:
>
> points (villages)
>
> some of them are outside of the raster not because an error but just
> because the point file is bigger in extent than the raster.
>
> Thank you very much in advance.
> Best,
>
> Manuel
>
>
> --
> *Manuel Spínola, Ph.D.*
> Instituto Internacional en Conservación y Manejo de Vida Silvestre
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