I became pretty interested in this topic not too long ago. Convex hulls are pretty well understood. I wanted to figure out a decent notion of "concave hull" (wh

I became pretty interested in this topic not too long ago. Convex hulls are pretty well understood. I wanted to figure out a decent notion of "concave hull" (which is not a uniquely defined construct, unlike the convex hull). It turns out alpha shapes are pretty well suited to this: http://bl.ocks.org/zpconn/11387143 http://bl.ocks.org/zpconn/11387143