Please try, at the end of your script: fullgrid(grid)=FALSE sel.grid <-grid[!is.na(clip),] points(sel.grid, col='blue', pch=3)
On 11/19/2011 03:38 PM, ASANTOS wrote: > Dear colleges, > > I need a help for selecting a grid inside the area with the > overlay() function, the idea is create a regular grid for all the area > and before select only the grid inside the sub area, my script for this > are: > > require(splancs) > require(sp) > #Create random points > x <- runif(n=500,min=0, max=20) > y <- runif(n=500,min=0, max=20) > xy<-cbind(x,y) > plot(x=x,y=y,axes=F, xlab="", ylab="", > xlim=c(-1,20),ylim=c(0,21)) > pt0 <- c(0.5,0.5)##First point of grid > ##Create sub area > limx<-c(2.5,2.5,18,18,2.5) > limy<-c(2.5,18,18,2.5,2.5) > lim=cbind(limx,limy) > lim<-as.matrix(lim) > ##Convert in spatial objects of sp package > #Random points > pontos <- SpatialPoints(cbind(x,y)) > pontos<- SpatialPoints(list(x,y)) > pontos<- SpatialPoints(data.frame(x,y)) > #Create the grid > grid0= GridTopology(c(0.5,0.5), c(1,1), c(20,20)) > grid<-SpatialGrid(grid = grid0) > ##Sub area > limite=SpatialPolygons(list(Polygons(list(Polygon(lim)),"lim"))) > ##For view > plot(limite)#Sub area > points(pontos)#Random points > points(grid,col='red')#Grid > clip<-overlay(grid,limite)##Select the grid inside the sub area > sel.grid <-grid[!is.na(clip),]##Removing Na's that represents the grid > outside the sub area > > But in this point I have a problem, there are any solution or other > approach for my problem, > Thanks, > -- 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