On 11/19/2011 04:03 PM, ASANTOS wrote: > Dear colleges, > > I need to create a object wit the coordinates of a grid and the > values in the point sampled, using the meuse.grid example: > > ## regular sampling over a grid > library(sp) > data(meuse.grid) > gridded(meuse.grid) = ~x+y > image(meuse.grid["dist"]) > points(spsample(meuse.grid,n=1000,type="regular"), pch=3, cex=.4) > > but here I don't how I can find the value in the image associated with > the grid, there are any suggestion?
> pts = spsample(meuse.grid,n=1000,type="regular") > over(pts, meuse.grid)[1:10,] part.a part.b dist soil ffreq 1 0 1 0.0000000 1 1 2 0 1 0.0000000 1 1 3 0 1 0.0054321 1 1 4 0 1 0.0000000 1 1 5 0 1 0.0000000 1 2 6 0 1 0.0000000 1 2 7 0 1 0.0000000 1 1 8 0 1 0.0264645 1 1 9 0 1 0.0537778 1 1 10 0 1 0.0593610 1 1 > dim(over(pts, meuse.grid)) [1] 1012 5 > class(over(pts, meuse.grid)) [1] "data.frame" see also http://cran.r-project.org/web/packages/sp/vignettes/over.pdf Hth, -- 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
