Thanks Roger, > head(row.names(LA)) [1] "0" "1" "2" "3" "4" "5" > head(row.names(CA)) [1] "0" "1" "2" "3" "4" "5" >
I'll have a look at these and get back with my results. Kind regards, Sean On Wed, Dec 2, 2009 at 3:07 PM, Roger Bivand <[email protected]> wrote: > On Wed, 2 Dec 2009, Sean O'Riordain wrote: > >> Good afternoon, >> >> I've been making good progress in the last few weeks thanks to this >> list, along with Roger and Adrians' books and some great geo-packages. >> >> I'm trying to combine some shapefiles... >> >> library(maptools) >> CA <- readShapePoly('ca.shp') >> LA <- readShapePoly('la.shp') >> >> Now I want to combine these two into a bigger object... >> >> I've searched the books and the internet and I've tried a number of >> things... including... >> >>> class(LA) >> >> [1] "SpatialPolygonsDataFrame" >> attr(,"package") >> [1] "sp" >>> >>> class(CA) >> >> [1] "SpatialPolygonsDataFrame" >> attr(,"package") >> [1] "sp" >>> >>> S1 <- unionSpatialPolygons(CA, LA) >> >> Loading required package: gpclib >> General Polygon Clipper Library for R (version 1.4-4) >> Type 'class ? gpc.poly' for help >> >> Error in unionSpatialPolygons(CA, LA) : input lengths differ >>> >>> >>> S1 <- spRbind(CA, LA) >> >> Error in spRbind(as(obj, "SpatialPolygons"), as(x, "SpatialPolygons")) : >> non-unique polygon IDs >>> > > Correct. Look at row.names(CA) and row.names(LA). Do something of your > choice to disambiguate them and re-assign with spChFIDs() - since you refer > to the ASDAR book, there is an example in chapter 5, sections 5.4 & 5.5, pp. > 120-126. You'll also see that your reading of how to use > unionSpatialPolygons() did not agree with that in the function, which is to > dissolve Polygons objects within an existing SpatialPolygons object. > > Hope this helps, > > Roger > >> >> Any ideas please? >> >> Thanks in advance! >> Sean >> >> _______________________________________________ >> R-sig-Geo mailing list >> [email protected] >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo >> > > -- > Roger Bivand > Economic Geography Section, Department of Economics, Norwegian School of > Economics and Business Administration, Helleveien 30, N-5045 Bergen, > Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 > e-mail: [email protected] > > _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
