[R] Concave hull

[baptiste auguie]

2009/11/26 Ted Harding <Ted.Harding at 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