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.
