Nonconvex boundary of 2d points?

Nonconvex boundary of 2d points?

Post by Vadim P. Shumili » Tue, 09 Nov 1999 04:00:00



Are there any algorithms for calculation of nonconvex boundary of a set of
points.
Yes, I understand that it is non unambigous, but nevertheless
for the set:

x1   xxxxxxxxxxxxxxxxxx
      x2xxxxxxxxxxxxxxxxxxx
                         x3xxxxxxxxxxxx
                                  x4xxxxxxxxxxx

             x5xxxxxxxxxxxxx

x6xxxxxxxxxxxxx

I wish to get   x1-x2-x3-x4-x5-x6   or   x1-x2-x3-x5-x6   or   x1-x5-x6
but not   x1-x6.

 
 
 

Nonconvex boundary of 2d points?

Post by Norbert Irme » Tue, 09 Nov 1999 04:00:00


This can be achieved by using "alpha-shapes". There is a good web-page
about these, but i forgot the URL, do a web-search.

> Are there any algorithms for calculation of nonconvex boundary of a set of
> points.
> Yes, I understand that it is non unambigous, but nevertheless
> for the set:

> x1   xxxxxxxxxxxxxxxxxx
>       x2xxxxxxxxxxxxxxxxxxx
>                          x3xxxxxxxxxxxx
>                                   x4xxxxxxxxxxx

>              x5xxxxxxxxxxxxx

> x6xxxxxxxxxxxxx

> I wish to get   x1-x2-x3-x4-x5-x6   or   x1-x2-x3-x5-x6   or   x1-x5-x6
> but not   x1-x6.