This might be a question for the R-SIG-Geo or R-SIG-Ecology lists. Best, Michael
On Wed, Mar 14, 2012 at 7:13 AM, Louise Mair <lm...@york.ac.uk> wrote: > Hello, > > I have a distribution dataset for species consisting of xy coordinates at > the 1km resolution, with only presence data. So a simplified example of a > species distribution might be: > > y <- rbind(as.integer(rnorm(100,50,20)), as.integer(rnorm(200,100,30)), > as.integer(rnorm(100,180,15))) > x <- rbind(as.integer(rnorm(200,50,20)), as.integer(rnorm(200,100,20)), > as.integer(rnorm(100,200,15))) > plot(y~x) > > I would like to create polygons for each species distribution, where if an > island is present (as I have tried to show in the example), it would be a > seperate polygon, and the jagged edges of coastlines etc are maintained. I > have spent ages trying to find a package that will allow me to convert > scattered point distributions to polygons but haven't found anything that > works, the functions I have found require the data already to be in the > format where the only xy coordinates present are the outline of the > polygon. > > Can anyone please recommend a function I can use here, or suggest a way of > extracting the outline points? I have tried this manually but cannot seem > to write a code that will effectively take account of jagged edges and > islands. > > Thanks very much for your help, > > Louise. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.