[GRASS5] [bug #242] (grass) R_polygon_abs() seems to ignoreislands

[Justin Hickey]

Hi Glynn and Eric

Glynn Clements wrote:
> I disagree; routines to tessellate arbitrary shapes into a set of
> non-overlapping convex polygons would be much more useful. It would
> make writing many vector algorithms much simpler.

Ahh yes, you're right. My mind was stuck in raster mode. :-)

But there should be a tessellation algorithm out there somewhere. I
looked in the Computer Graphics book I mentioned and the only reference
to tesselation is a question left for students. However, there is a
reference for a book with that question. The book is "Computational
Geometry: An introduction" by F. P. Preparata and M. I. Shamos. Perhaps
this book (or another one with the same subject) has an algorithm we can
use or modify? Just a suggestion.

-- 
Sincerely,

Jazzman (a.k.a. Justin Hickey)  e-mail: jhickey at hpcc.nectec.or.th
High Performance Computing Center
National Electronics and Computer Technology Center (NECTEC)
Bangkok, Thailand
==================================================================
People who think they know everything are very irritating to those
of us who do.  ---Anonymous

Jazz and Trek Rule!!!
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