Dear r-helpers, I have a graph created using the library 'spatgraphs'. library(spatstat) library(spatgraphs) xy <- rbind(c(28.39, -16.27), c(30.62, -20.13), c(32.25, -28.7), c(22.43, -27.22), c(27.5, -21.17), c(31.22, -24.52), c(17.93, -26.92), c(18.72, -17.95), c(24.15, -17.82), c(29.23, -22.85)) ow <- owin(xrange=range(xy[,1]), yrange=range(xy[,2])) pp <- ppp(x=xy[,1],y=xy[,2],n=nrow(xy),window=ow) gg <- spatgraph(pp=pp, type="gabriel") plot(gg, asp=1, pp=pp, add=FALSE) lines(xy[c(1,2,10,6,3,4,7,8,9,1),],col=2,lwd=2) and now I need to automatically extract polygon corresponding to its outer boundary, highlighted here in red. Are you aware of such function in R? I looked for it hard but with no success. Thank you in advance for any hint. Ondřej -- Ondřej Mikula Institute of Animal Physiology and Genetics Academy of Sciences of the Czech Republic Veveri 97, 60200 Brno, Czech Republic Institute of Vertebrate Biology Academy of Sciences of the Czech Republic Studenec 122, 67502 Konesin, Czech Republic [[alternative HTML version deleted]]