Oh right.... I think I did not catch that *because of* the caps. Sorry. r
------------------------------------------------- Remko Duursma Post-Doctoral Fellow Centre for Plants and the Environment University of Western Sydney Hawkesbury Campus Richmond NSW 2753 Dept of Biological Science Macquarie University North Ryde NSW 2109 Australia Mobile: +61 (0)422 096908 www.remkoduursma.com On Thu, Nov 26, 2009 at 10:51 AM, Barry Rowlingson <b.rowling...@lancaster.ac.uk> wrote: > On Wed, Nov 25, 2009 at 11:39 PM, Remko Duursma <remkoduur...@gmail.com> > wrote: >> See the function 'convhulln' in the 'geometry' package. It uses this >> algorithm : http://www.qhull.org/ > > That looks like a CONVEX hull, the original poster asked about > CONCAVE hulls (and in all CAPS to emphasise this!). > > I've seen various algorithms for generating 'concave hulls' of point > sets, the one that tops google searches is not available in source > code but there is a web applet and set of java class files which > appear to be based on a patented algorithm. > > There's a lot of discussion on algorithms for this, and some > implementations by processing the point data with GRASS. There main > discussion appears to be to first generate the convex hull and then > replace single edges with two edges based on some minimum or maximum > distance criteria... > > Couldn't find an implementation in R or Python though... > > Barry > ______________________________________________ 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.