On Wed, 2 Dec 2015 at 23:10 Adrian Dușa <dusa.adr...@unibuc.ro> wrote:
> Dear All, > > I know how to fill a polygon, using a basic R graphics device: > > par(mai=c(0, 0, 0, 0)) > plot(1:100, type="n") > polygon(c(20, 80, 80, 20), c(20, 20, 80, 80), col="lightblue") > > > But let's say I have an outer polygon like this: > polygon(c(0,100,100,0), c(0,0,100,100)) > > Is it possible to fill the area between the two polygons? > > Try polypath with the evenodd rule (vs. the winding rule): p1 <- list(x = c(20, 80, 80, 20), y= c(20, 20, 80, 80)) p2 <- list(x = c(0,100,100,0), y = c(0,0,100,100)) plot(p2, type="n") polypath(x = c(p1$x, NA_real_, p2$x), y = c(p1$y, NA_real_, p2$y), col = "lightblue", rule = "evenodd") Cheers, Mike. > I realise there is a quick and dirty solution to fill the outer polygon, > then draw the inner polygon colored with white, but I would like to > actually "clip" the outer polygon to the boundaries of the inner one. > > Of course, there are various packages which draw maps (i.e. maptools), but > I need this in base R graphics. In other words, is it possible to define a > polygon with a hole inside, in base R? > > Thank you, > Adrian > > -- > Adrian Dusa > University of Bucharest > Romanian Social Data Archive > Soseaua Panduri nr.90 > 050663 Bucharest sector 5 > Romania > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
