Thanks for the interesting reference to alphahull. It might be a good starting point for placing e.g. a legend in a plot (I think the usual techniques for this (gregmisc?) are a bit more brute-force.)
baptiste 2009/11/27 Kjetil Halvorsen <kjetilbrinchmannhalvor...@gmail.com>: > There is a package on CRAN implementing such an idea: > alphahull, phull is other package, > > kjetil > > On Thu, Nov 26, 2009 at 6:11 PM, baptiste auguie > <baptiste.aug...@googlemail.com> wrote: >> 2009/11/26 Ted Harding <ted.hard...@manchester.ac.uk>: >>> Raising a rather general question here. >>> >>> This is a tantalising discussion, but the notion of "concave hull" >>> strikes me as extremely ill-defined! >>> >>> I'd like to see statement of what it is (generically) supposed to be. >> >> I'm curious too, but I can imagine the following definition, >> >> Consider a sphere (n-dimensional maybe) that we let come in contact >> with the scatter of points from outside. The set of points that the >> sphere can attain may define unambiguously (I think) a concave hull, >> for a specified sphere radius. The convex hull is obtained in the >> limit of infinite radius (plane). >> >> It's probably not exactly this, but I guess that's the rough idea. >> >> Just a thought, >> >> baptiste >> >> ______________________________________________ >> 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.