It seems that your question has nothing to do with spplot (which is a method in package sp), as you are using plot(). If the problem is similar to this:
> plot(1:10,xlim=c(0,11),ylim=c(0,11)) > par()$usr [1] -0.44 11.44 -0.44 11.44 then it doesn't have to do anything with plotting map data, and r-help might be the more suitable list to ask. The following might help: > plot(1:10,xlim=c(0,11),ylim=c(0,11),xaxs="i", yaxs="i") > par()$usr [1] 0 11 0 11 Best regards, On 11/28/2011 09:20 PM, Jonathan Callahan wrote: > I am plotting spatial data on transparent backgrounds for overlay on top of > a GoogleMaps interface but they aren't *exactly* right. > > I have set the size of GoogleMaps and my image to 640X640 and I receive > bounds information on the current region from the GoogleMaps javascript API. > > The problem is that the image generated by spplot does not strictly adhere > to the xlim and ylim parameters I am passing in. > > As an example, here is some debugging of a plot of watershed basins > > print(paste("map_west = ",w,", map_east =",e,", map_south = ",s,", > map_north = ",n)) > xlim = c(w,e) > ylim = c(s,n) > plot(basin,xlim=xlim,ylim=ylim,border=col_basin,lwd=lwd_basin) > print(paste("usr_west = ",format(par()$usr[1],digits=7,nsmall=4),", > usr_east =",format(par()$usr[2],digits=7,nsmall=4), > ", usr_south = ",format(par()$usr[3],digits=6,nsmall=4),", > usr_north = ",format(par()$usr[4],digits=6,nsmall=4))) > > And here is the resulting text output: > > [1] "map_west = -124.4348 , map_east = -123.6252 , map_south = 43.8856 , > map_north = 44.4652" > [1] "usr_west = -124.4672 , usr_east = -123.5928 , usr_south = 43.8618 , > usr_north = 44.4890" > > > Things are close but not *exactly* right. Is there anything I can do to > force spplot to stick to the boundaries I have passed in? > > I am using R 2.13.1 and sp 0.9-85. > > Thanks in advance. > -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de http://www.52north.org/geostatistics e.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo