On Wednesday 12 March 2008, Roger Bivand wrote: > On Wed, 12 Mar 2008, Dylan Beaudette wrote: > > On Thursday 06 March 2008, Thomas Adams wrote: > >> Dylan, > >> > >> I think a solution using GRASS can be found on pages 110-111 of "Open > >> Source GIS: A GRASS GIS Approach", 3rd Ed. The same material is covered > >> in the 2nd Ed. as well, where you use r.mapcalc to combine two rasters > >> and judicious use of MASKs; a conditional statement in r.mapcalc is the > >> key. > >> > >> Regards, > >> Tom > > > > Hi Tom, > > > > Thanks for the suggestion. This works, but we were hoping to make the > > plot in R-- as the PDF output is hard to match with GRASS alone. I > > suppose I will just have to try using two rasters with spplot() and see > > what happens. > > The problem is that customising a panel to insert an image probably means > writing just that, customised panels, and spplot() essentially does that > already. You could look at Chapter 5 in Paul Murrell's book, to see how to > insert grid output into lattice output (to try to put an image as a > backcloth, but there is no example for this case - the example is for > adding a location position. > > My guess would be that if you are only displaying a single panel, you will > find it easier to use base graphics, and simply say image() twice, and use > legend() (or legend.krige() from geoR). > > Roger
Thanks for the tips Roger. I think that in this case it will be simplest to use multiple calls to image(). Cheers, Dylan > > Cheers, > > > > Dylan > > > >> Dylan Beaudette wrote: > >>> On Tuesday 04 March 2008, Edzer Pebesma wrote: > >>>> I find it hard to imagine how you want to plot two raster files on top > >>>> of each other. Do you want some form of transparency? If it is just > >>>> one overlaying the other, you could use overlay to find out which > >>>> cells in raster 1 to replace with those in raster 2 before plotting. > >>>> -- > >>>> Edzer > >>> > >>> Hi Edzer, > >>> > >>> I generally agree that plotting one raster file "over" another raster > >>> file would be of little use. In this case, one of the raster files (the > >>> interesting one) has been masked with nodata, such that it only really > >>> covers about 30% of the region of interest. The other raster is just > >>> contextual data, and thus would be useful to plot "behind" the first > >>> raster. > >>> > >>> Ideas? > >>> > >>> Dylan > >>> > >>>> Dylan Beaudette wrote: > >>>>> Hi, > >>>>> > >>>>> Is it possible to plot two raster images using spplot() in a manner > >>>>> similar to: > >>>>> > >>>>> pts <- list("sp.points", points_file, pch = 4, col = "black", > >>>>> cex=0.5) spplot(raster_file, zcol="elev.pred", sp.layout=list(pts)) > >>>>> > >>>>> Note that one of the raster images is an aerial photo, used only for > >>>>> context, while the second one is one with interesting z-values. The > >>>>> second raster is masked and thus does not cover the entire region. > >>>>> > >>>>> Thanks, > >>>>> > >>>>> Dylan -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo