If I got your question well, for the raster r <- raster(matrix(rep(c(1:10),10),10,10)) and vector v <- c(1:3)
You can change to 1 all the values of raster equal to the elements of vector v with: r[r%in%c(1,2,3)] <- 1 and then, everything else to NA with: r[!r%in%c(1)] <- NA HTH, jed _______________________________ Jedrzej Stanislaw BOJANOWSKI European Commission Joint Research Centre Institute for Environment and Sustainability Monitoring Agricultural Resources Unit - H04 Crop Production Forecast and Climate Change Impact Via Fermi 2749, I-21027 ISPRA (VA), ITALY +39.0332.78.5030 jedrzej.bojanow...@jrc.ec.europa.eu http://mars.jrc.ec.europa.eu/mars jbojanowski.pl > -----Original Message----- > From: r-sig-geo-boun...@r-project.org [mailto:r-sig-geo-bounces@r- > project.org] On Behalf Of Daisy Englert Duursma > Sent: 19 March, 2012 11:53 AM > To: r-sig-geo@r-project.org > Subject: [R-sig-Geo] select cells in a raster and change the values to > 1 > > Greetings, > > I have a vector of values and I want to select cells in a raster that > have these values, change these cells so they have a value of 1 and the > rest of the raster will have a NA value. > > library(raster) > > #my example raster > r <- raster(ncol=3, nrow=3) > r[] <- 1:ncell(r) > #a vector of cells I want to select > vals<-c(2,4,6) > > #I want to select cells with the values 2,4,6 a silly way to do it: > r1<-r==2 > r2<-r==4 > r3<-r==6 > #make the final desired raster > r4<-r1+r2+r3 > plot(r4) > > #I have played around with a lot of differnt things but I think I want > to use the funcion sub ######this does not work###### df = > data.frame(id=c(2,4,6), v=c(1,1,1)) x = subs(r, df) > > > > Is there a better way to do this? There must be a better way. What have > I missed? I need to be able to select raster cells from a vector. > > Thank you for your time and help, > Daisy > > > -- > Daisy Englert Duursma > Department of Biological Sciences > Room E8C156 > Macquarie University, North Ryde, NSW 2109 Australia > > Tel +61 2 9850 9256 > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo