[postgis-users] simplify weirdnesses
Paul Ramsey
pramsey at refractions.net
Tue Feb 17 10:06:57 PST 2004
Markus Schaber wrote:
> Is it desired that a PostGIS operation on valid geometries can make them
> non-valid?
>
> And it seems that some (well, 65 thousand) Geometries even get
> deleted by simplify.
It is not desired, but doing otherwise is exceptionally hard. Running
D-P on polygons in particular is almost certain to cause invalid
geometries to arise (think about the process of thinning vertices out of
a polygon -- unless the polygons are completely convex eventually you
will cause self-intersections). General simplification routines for
polygons are rocket science.
--
__
/
| Paul Ramsey
| Refractions Research
| Email: pramsey at refractions.net
| Phone: (250) 885-0632
\_
More information about the postgis-users
mailing list