Alpha shape (non-convex hull)

May 10, 2013 at 2:35 AM
Hi,

Is there a method in dotspatial to return alpha shape from list of points?

I found a method to calculate ConvexHull() but I need alpha shape(concave hull).
                        var multiPoint = new MultiPoint(coords);
                        var convexHull = multiPoint.ConvexHull().Buffer(0.0001);
Can anyone help? Thanks.
Coordinator
May 10, 2013 at 2:53 PM
I'm not sure I understand. what do you mean by alpha shape?
May 13, 2013 at 6:00 AM
Thanks for the reply. A concave hull/alpha shapes. Something like the image below.
Image

Thanks again
Coordinator
May 13, 2013 at 3:25 PM
OK thanks for the pictures... they are worth a thousand words - or at least several dozen. As far as I know this function does not exist in DotSpatial. If you can find a good algorithm for it, maybe we should consider adding it...
May 14, 2013 at 9:17 AM
I found one here. Don't know if it's enough. Thanks.
Aug 3, 2014 at 12:40 PM
i have found another algorithm for it:

Implementation of a fast and efficient concave hull algorithm pdf

can you please implement it?

thanks