Here is another example with overlay from the Reimann et al. (2008) book (this uses a raster map as background - this if often more impressive):
http://www.statistik.tuwien.ac.at/StatDA/R-scripts/page151.html The code is rather long, but it will give you good ideas what you have to do. HTH T. Hengl > On Sun, Aug 16, 2009 at 12:20 PM, Rebecca > Ross<rebecca.r...@plants.ox.ac.uk> wrote: >> >> Dear All, >> >> I am new to this list, so apologies if this question has been asked and >> answered many times before! >> >> I would like to overlay a bubble chart onto a map so that the bubbles >> correspond to particular points on the map. I have the shape file for >> the map >> and the lat long co-ordinates for the points. Could anyone tell me how >> to put >> the two together? The suggestions I found so far are plot.Map and >> plot.Spatial, >> neither of which work. >> >> I am working to a bit of a deadline, so a response today would be really >> helpful. > > To read foo.shp: > > install.packages("rgdal") > > require(rgdal) > map = readOGR("/path/to/maps/","foo") > plot(map) > > then you can do: > > points(p$x,p$y) > > or whatever to overlay on it. If a 'bubble chart' is just points > scaled by some factor, you can either use the 'symbols' function in R > or use pch and cex options to plot - with something like: > > p = data.frame(x=1:10,y=1:10,size=1:10) > plot(p$x,p$y,pch=19,cex=p$size) > > hope that helps! > > Barry > > _______________________________________________ > 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