spgpc package?
e.g.
# x is a gpc.poly object
as.Polygons.gpc.poly <- function(x, ID) {
thisPolys <- lapply(get.pts(x), function(p) {
Polygon(rbind(as.matrix(cbind(p$x,p$y)),c(p$x[1],p$y[1])),
hole=p$hole)
})
Polygons(thisPolys, ID)
}
This works except if the gpc.poly is empty. `Polygons` fails if passed
an empty list().
Felix
On 8/9/07, Felix Andrews <felix at nfrac.org> wrote:
Hmm I'm trying to work with gpclib, converting to and from the sp classes. I don't know what is/was in the package spgpc, but it is no longer available:
install.packages("spgpc", repos=rSpatial)
Warning: unable to access index for repository http://r-spatial.sourceforge.net/R/bin/windows/contrib/2.5 The page http://r-spatial.sourceforge.net/xtra/xtra.RHnw.html says: "the functionality described here has been included in packages rgdal, naptools, and spgrass6, now all on CRAN. This page is maintained for documentary purposes only, and most of the examples shown here are the examples used in the released packages." where i'm guessing "naptools" should be "maptools". But I can not find a method to coerce between "gpc.poly" and "Polygons" classes. Not that it is difficult to manually... just wondering. Felix -- Felix Andrews / ??? PhD candidate Integrated Catchment Assessment and Management Centre The Fenner School of Environment and Society The Australian National University (Building 48A), ACT 0200 Beijing Bag, Locked Bag 40, Kingston ACT 2604 http://www.neurofractal.org/felix/ voice:+86_1051404394 (in China) mobile:+86_13522529265 (in China) mobile:+61_410400963 (in Australia) xmpp:foolish.android at gmail.com 3358 543D AAC6 22C2 D336 80D9 360B 72DD 3E4C F5D8