On Wednesday 05 March 2008, Steve Friedman wrote: > My two cents > > This sounds like a GIS type operation rather than an analytical process > model that requires R. If so use ARC/INFO
Right-- this is just a plotting operation. The spplot function is very useful when working with data in R, and it would be nice to produce a "finished" figure within the context of the R session. Writing the data back to the GIS and finishing the map there works, but the operation cannot be eloquently contained within an R source file. > Does the "context" raster provide data in the sense of quantitative needs > or is it a categorical raster that shows classes of information such as > land use? the context raster is just an aerial image. I would like to overplot the "interesting" raster. Dylan > Now - would it make more sense to combine these using some kind of union > process (I don't know how to do this in R) to show the quantitative raster > data in the categorical classes. Then you can delete the larger context > raster which does not contain any information and reduce the window > (spatial extent) of the overlaid model. > > Steve > > On Wed, Mar 5, 2008 at 12:45 PM, Dylan Beaudette > <[EMAIL PROTECTED]> > > 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