Need help with finding perimeters of bounded areas

[David H. West]

In article <135 at unicom.UUCP> miller at unicom.UUCP (Gregory S Miller) writes:
>Consider an area A on an euclidean plane surface.  Inside A 
>are an arbitrary number of lines that "fill out" A.  That is,
>A is defined not by a perimeter, but rather as a filled object (
>negative versus positive images...).

>Problem: Given the area A, find the perimeter - eliminate all lines
>	 inside A and leave just the outline.  A is "given" by a
>	 list of vectors with a diameter (ie. start/end point with
>	 diameter). 

I imagine one could simplify one of the perimeter-marching convex hull
algorithms fairly straightforwardly to do this. See e.g.
Preparata and Shamos, Computational Geometry, Springer, 1985.

-David West        dhw at itivax.iti.org