You can easily clip rasters with polygons (or other rasters) via raster package.
See this recent thread<http://r-sig-geo.2731867.n2.nabble.com/Clip-a-raster-td5635474.html>for one example using crop() and polygonsToRaster() functions. Other than that, the packages has comprehensive vignettes and maybe that's the place to start. Cheers, Roman On Tue, Oct 19, 2010 at 1:41 PM, Thiago Veloso <thi_vel...@yahoo.com.br>wrote: > Dear R-SIGgers, > My current rainfall dataset (ascii, at 0.2 degree resolution) spans the > entire South America and has been loaded into R as a xyz variable: > > summary(prec_data) V1 V2 V3 > Min. :-82.80 Min. :-50.20 Min. : 0.000 1st Qu.:-70.65 1st > Qu.:-34.65 1st Qu.: 0.000 Median :-58.50 Median :-19.10 Median : > 0.000 Mean :-58.50 Mean :-19.10 Mean : 4.002 3rd Qu.:-46.35 > 3rd Qu.: -3.55 3rd Qu.: 2.430 Max. :-34.20 Max. : 12.00 Max. > :250.150 > head(prec_data) V1 V2 V31 -82.8 -50.2 0.002 -82.8 > -50.0 1.363 -82.8 -49.8 2.864 -82.8 -49.6 3.635 -82.8 -49.4 3.266 -82.8 > -49.2 3.40> > My objectives are the following: > 1) Clip the data using a shapefile; > 2) In order to completely fill the area with rainfall information, > perform a interpolation technique (IDW or kriging) using as boundary the > same shapefile above. This will allow me to generate risk maps for the > occurence of a certain plant disease. > Could anybody please point me the directions on how to do this? > Thanks in advance, > Thiago. > > > > [[alternative HTML version deleted]] > > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > -- In God we trust, all others bring data. [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
