Ariel,
That's a bug introduced in the last version, it seems. Fixed in
version 1.9-86 that I will release soon.
Robert


On Mon, Apr 23, 2012 at 8:13 PM, Ariel Ortiz-Bobea <aortizbobea@arec.umd.edu
> wrote:

> Hello,
>
> In the past I've managed to extract weights using the raster package on
> SpatialPolygons. Now when try to extract the weights I get an empty list on
> my platform...
>
> I'm simply trying to reproduce this example by Robert J. Hijmans:
>
>    /  library(raster)
>
>      r <- raster(ncol=36, nrow=18)
>      r[] <- 1:ncell(r)
>      cds1 <- rbind(c(-180,-20), c(-160,5), c(-60, 0), c(-160,-60),
> c(-180,-20))
>      cds2 <- rbind(c(80,0), c(100,60), c(120,0), c(120,-55), c(80,0))
>      polys <- SpatialPolygons(list(Polygons(list(Polygon(cds1)), 1),
>                                    Polygons(list(Polygon(cds2)), 2)))
>
>      # visualize
>      plot(r)
>      plot(polys, add=T)
>
>      # extract the cellnumbers and weights
>      v <- extract(r, polys, weights=TRUE, cellnumbers=TRUE)
>      v/
>
> This is what I get for v:
>
> /[[1]]
> NULL
>
> [[2]]
> NULL/
>
> I'm using the latest raster version (1.9-82 (5-April-2012)) and R 2.15.0 I
> downgraded to 2.14.2 on a MacOS and still doesn't work (on two different
> computers). I went to another machine running on Windows and raster package
> v. 1.8-12 (11-April-2011) on R 2.11.1 and it DID work.
>
> So I guess it's about the version of the package? I don't understand what
> is
> going on. Any suggestion would be appreciated!
>
> Thanks.
>
> Ariel
>
>
> -----
> Ariel Ortiz-Bobea
> PhD Candidate in Agricultural & Resource Economics
> University of Maryland - College Park
> --
> View this message in context:
> http://r-sig-geo.2731867.n2.nabble.com/raster-extract-function-not-working-in-latest-package-tp7493919p7493919.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
>
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