Hi In your case I guess you only need part 1. If there are more than 1 polygon you would also need part 2. As far as i know there are no inbuilt functions to extract coordinates from a SpatialPolygon.
## #part 1 nc <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1], proj4string=CRS("+proj=longlat +datum=NAD27")) lonlat <- lapply(slot(nc, "polygons"), function(x) lapply(slot(x, "Polygons"), function(y) slot(y, "coords"))) #part 2 for (i in 1:dim(summary(lonlat))[1]) { size <- length(unlist(lapply(lapply(lonlat[i], lapply, dim), unlist))) if (size == 2) { res2 <- data.frame(unlist(lonlat[i], recursive=FALSE)) } else lonlat.tmp <- unlist(lonlat[i], recursive=FALSE) if (size != 1) lonlat2 <- do.call(rbind, lapply(lonlat.tmp, data.frame)) res2$ID <- i if (i == 1) lonlat3 <- lonlat2 else lonlat3 <- rbind(lonlat3, lonlat2) } lonlat3 ## Maybe this could be more efficient (part 2), but at least it works. Best wishes Torleif On Thursday 19 March 2009 10:14:51 pm Tyler Dean Rudolph wrote: > Hi there, > > Nestled deep within the "polygons" slot of my SpatialPolygonsDataFrame > object is a list of xy coordinates I would like to extract. Using > coordinates() only produces a single xy pair associated with the polygon > (1st entry? Centroid?) and I cannot for the life of me manage another way, > though I presume it is far from impossible. Could someone please direct me > on this? > > Cheers > Tyler > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo