Interesting. Works for me "out of the box". > sessionInfo() R version 2.11.0 (2010-04-22) i386-pc-mingw32
locale: [1] LC_COLLATE=Slovenian_Slovenia.1250 LC_CTYPE=Slovenian_Slovenia.1250 [3] LC_MONETARY=Slovenian_Slovenia.1250 LC_NUMERIC=C [5] LC_TIME=Slovenian_Slovenia.1250 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] raster_1.0.4 sp_0.9-62 loaded via a namespace (and not attached): [1] grid_2.11.0 lattice_0.18-5 Cheers, Roman On Tue, Jun 22, 2010 at 10:37 AM, Michael Sumner <mdsum...@gmail.com> wrote: > Sorry, but it still doesn't work for me. I'm surprised you could get > passed the first line, since "projs" is not an argument to raster - > it's not necessary for your example to have that set though, so I > ignore it. > > I had to install igraph package as well, but still this fails at the > gridDistance line. Can you let us know your OS, R and package versions > for raster, sp, and igraph? Use sessionInfo() please. > > library(raster) > library(sp) > library(igraph) > > rst <- raster(nrow = 200, ncol = 200, xmn = -100, xmx = 100, ymn = > -100, ymx = 100) > sample.matrix <- t(matrix(c(50,-50, 50,50, -50,50, -50,-50), 2, 4)) > sample.matrix <- rbind(sample.matrix, sample.matrix[1,]) > sq.polygon <- SpatialPolygons(list(Polygons(list(Polygon(sample.matrix)), > ID = "effect_dist"))) > rst[] <- runif(ncell(rst)) > xy <- matrix(c(0,0), 1, 2) > > rst.poly <- polygonsToRaster(sq.polygon, rst) > rst.lines <- linesToRaster(sq.polygon, rst) > > rst.lines[rst.lines > 0] <- 0 > > rst.point <- pointsToRaster(rst, xy) > > rst.cover <- cover(rst.point, rst.lines) > > ## fails at this line > rst.grid <- gridDistance(rst.cover) > rst.grid[!is.na(rst.lines)] <- NA > plot(rst.grid) > > sessionInfo() > > R version 2.11.1 (2010-05-31) > x86_64-pc-mingw32 > > locale: > [1] LC_COLLATE=English_Australia.1252 LC_CTYPE=English_Australia.1252 > LC_MONETARY=English_Australia.1252 > [4] LC_NUMERIC=C LC_TIME=English_Australia.1252 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > other attached packages: > [1] igraph_0.5.3 raster_1.1.7 sp_0.9-64 > > loaded via a namespace (and not attached): > [1] grid_2.11.1 lattice_0.18-8 tools_2.11.1 > > > On Tue, Jun 22, 2010 at 6:28 PM, Roman Luštrik <roman.lust...@gmail.com> > wrote: > > Thank you Michael for taking interest in my problem. Here is the code > that > > should work. The only difference is that here, for a polygon, I use a > square > > instead of a circle (no biggie). I suspect gridDistance may have > something > > to do with the "hexagon". > > > > library(raster) > > library(sp) > > rst <- raster(nrow = 200, ncol = 200, xmn = -100, xmx = 100, ymn = -100, > ymx > > = 100, projs = "+proj=NA") > > sample.matrix <- t(matrix(c(50,-50, 50,50, -50,50, -50,-50), 2, 4)) > > sample.matrix <- rbind(sample.matrix, sample.matrix[1,]) > > sq.polygon <- SpatialPolygons(list(Polygons(list(Polygon(sample.matrix)), > ID > > = "effect_dist"))) > > rst[] <- runif(ncell(rst)) > > xy <- matrix(c(0,0), 1, 2) > > > > rst.poly <- polygonsToRaster(sq.polygon, rst) > > rst.lines <- linesToRaster(sq.polygon, rst) > > > > rst.lines[rst.lines > 0] <- 0 > > rst.point <- pointsToRaster(rst, xy) > > > > rst.cover <- cover(rst.point, rst.lines) > > rst.grid <- gridDistance(rst.cover) > > rst.grid[!is.na(rst.lines)] <- NA > > plot(rst.grid) > > > > > > Cheers, > > Roman > > > > > > > > > > On Tue, Jun 22, 2010 at 9:55 AM, Michael Sumner <mdsum...@gmail.com> > wrote: > > > >> Could you please provide a reproducible example with useable code? > >> > >> Cheers, Mike. > >> > >> On Tue, Jun 22, 2010 at 5:36 PM, Roman Luštrik <roman.lust...@gmail.com > > > >> wrote: > >> > Can someone explain to me why values of distances from a point are not > in > >> a > >> > uniform, circle-like fashion, but rather form a hexagon shape (see > >> > image<http://imagepaste.nullnetwork.net/viewimage.php?id=1075>)? > >> > Here is the code I'm using to produce this plot (kudos to > >> > Robert< > >> > http://r-sig-geo.2731867.n2.nabble.com/assigning-raster-cell-values-based-on-predefined-criteria-td4929775.html#a4929775 > >> >). > >> > Raster projection is "+projs = NA". > >> > > >> > rst.poly <- polygonsToRaster(circle.polygon, rst) #circle.polygon is > the > >> > polygon I'm overlaying, rst is the raster > >> > rst.lines <- linesToRaster(circle.polygon, rst) > >> > rst.lines[rst.lines > 0] <- 0 > >> > rst.point <- pointsToRaster(rst, xy[[i]][j,]) #xy is the point from > where > >> > the distances are calculated > >> > rst.cover <- cover(rst.point, rst.lines) > >> > rst.grid <- gridDistance(rst.cover) > >> > rst.grid[!is.na(rst.lines)] <- NA > >> > plot(rst.grid) > >> > > >> > > >> > Cheers, > >> > Roman > >> > > >> > > >> > -- > >> > 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 > >> > > >> > > > > > > > > -- > > In God we trust, all others bring data. > > > > > > > > -- > > 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 > > > > > -- In God we trust, all others bring data. 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