[geos-devel] geometry validation and simplfiy problem

[Martin Davis]

> i will try buffer(0). will buffer(0) simplify a 
> self-intersected polygon?

Yes, it should do.  Post back once you've tried it and let us know if it
works in your situation.

Martin Davis, Senior Technical Architect
Vivid Solutions Inc.      www.vividsolutions.com
Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046


> -----Original Message-----
> From: geos-devel-bounces at geos.refractions.net 
> [mailto:geos-devel-bounces at geos.refractions.net] On Behalf Of 
> zhangjing
> Sent: July 14, 2006 7:43 PM
> To: GEOS Development List
> Subject: Re: RE: [geos-devel] geometry validation and simplfiy problem
> 
> 
> thanks Martin,
> 
> >Not currently, but it would be nice to have.  I have done 
> some work in 
> >this direction, but it's not really in a releasable state.
> 
> yes, really looking forward. 
> 
> 
> >When you "simplify" a polygon with a hole which crosses outside the 
> >outer shell, what happens to the part that is outside?  Does it 
> >disappear, or become another polygon?
> 
> i believe it will become another polygon. i think all i want 
> is to make the 
> LineRings into topology correct polygon(multipolygon). 
> 
> >One thing you can do which should work almost all the time is to run
> >buffer(0) on the invalid polygon.  Buffer is very tolerant of bad 
> >topology, and will generally fix the polygon in the way I 
> suspect you 
> >are looking for.
> >
> 

> 
> thanks.
> 
> 
> 
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