[geos-devel] [Horst.Duester@bd.so.ch: AW: [postgis-users] Dissolve obsoletepolygon borders]

[Martin Davis]

> I mean: does it have to do with malformed/unsupported input geometries
> or with bogus GEOS code ? Any hint on this ?

Almost certainly neither.  Instead, this is an example of the known limitations with robustness handling in JTS/GEOS.  Unfortunately, currently there's no 100% workaround for this, at least not in the context of PostGIS.

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



> -----Original Message-----
> From: strk [mailto:strk at keybit.net]
> Sent: Tuesday, October 21, 2003 7:53 AM
> To: geos-devel at geos.refractions.net
> Subject: [geos-devel] [Horst.Duester at bd.so.ch: AW: [postgis-users]
> Dissolve obsoletepolygon borders]
> 
> 
> Are these bugs or normal administration ?
> I mean: does it have to do with malformed/unsupported input geometries
> or with bogus GEOS code ? Any hint on this ?
> 
> Horst, please, continue this on the mailing list.
> 
> --strk;
> 
> ----- Forwarded message from Düster Horst 
> <Horst.Duester at bd.so.ch> -----
> 
> From: Düster Horst <Horst.Duester at bd.so.ch>
> To: "'strk'" <strk at keybit.net>
> Subject: AW: [postgis-users] Dissolve obsolete polygon borders
> Date: Tue, 21 Oct 2003 11:23:30 +0100
> 
> strk
> 
> Now Postgis responses with the following NOTICE/MESSAGE
> 
> NOTICE:  TopologyException: side location conflict (628374,239597)
> ERROR:  GEOS union() threw an error!
> 
> 
> Horst
> 
> -----Ursprüngliche Nachricht-----
> Von: strk [mailto:strk at keybit.net]
> Gesendet am: Montag, 20. Oktober 2003 15:05
> An: Düster Horst
> Cc: geos-devel at geos.refractions.net
> Betreff: Re: [postgis-users] Dissolve obsolete polygon borders
> 
> There are two cases for this to happen, can you update your 
> GEOS sources
> and try again (a more explicit exception message have been introduced)
> 
> --strk;
> 
> Horst.Duester wrote:
> > strk
> > 
> > I recompiled GEOS and PostGIS and tied to dissolve the 
> large table. Now
> GEOS
> > responsed with a NOTICE:
> > 
> > NOTICE:  AssertionFaiedException: found null Directed Edge
> > ERROR:  GEOS union() threw an error!
> > 
> > Horst
> > 
> > -----Ursprüngliche Nachricht-----
> > Von: strk [mailto:strk at keybit.net]
> > Gesendet am: Donnerstag, 16. Oktober 2003 16:57
> > An: Düster Horst
> > Betreff: Re: [postgis-users] Dissolve obsolete polygon borders
> > 
> > Do you have heterogeneous geometries in your table ?
> > 
> > --stkr;
> > 
> > Horst.Duester wrote:
> > > Ok. Now I tried to dissolve a large table with more than 
> 80'000 Records.
> > > After nearly 20 Minutes of processing time PostGIS breakes with 
> > > 
> > > GEOS union() threw an error!
> > > 
> > > A NOTICE didn't appear. 
> > > 
> > > Horst
> > > 
> > > 
> > > 
> > > 
> > > -----Ursprüngliche Nachricht-----
> > > Von: strk [mailto:strk at keybit.net]
> > > Gesendet am: Donnerstag, 16. Oktober 2003 16:16
> > > An: Düster Horst
> > > Betreff: Re: [postgis-users] Dissolve obsolete polygon borders
> > > 
> > > Didn't you get an Exception thrown ?
> > > 
> > > Horst.Duester wrote:
> > > > Thank you for your response. I doesn't work, PostgreSQL 
> responses with
> > > > "GEOS union() threw an error!".
> > > 
> > > Please, check if that error is now more meaningful.
> > > A NOTICE should appear right before that response.
> > > 
> > > --strk;
> > > 
> > > Horst.Duester wrote:
> > > > Yes, great now it works and I'm able to dissolve my 
> geometry. Thank
> you
> > > very
> > > > much for your efforts and your time you spent for me.
> > > > 
> > > > Horst
> > > > 
> > > > 
> > > > 
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: strk [mailto:strk at keybit.net]
> > > > Gesendet am: Donnerstag, 16. Oktober 2003 08:21
> > > > An: PostGIS Users Discussion
> > > > Cc: Horst.Duester at bd.so.ch
> > > > Betreff: Re: [postgis-users] Dissolve obsolete polygon borders
> > > > 
> > > > Horst.Duester wrote:
> > > > > strk
> > > > > 
> > > > > Thank you for your response. I doesn't work, 
> PostgreSQL responses
> with
> > 
> > > > > "GEOS union() threw an error!".
> > > > > 
> > > > > Horst
> > > > 
> > > > Try downloading the latest postgis from CVS repository, it now
> contains
> > > > new code to show a more meaningful message (thanks Dave).
> > > > 
> > > > --strk;
> > > > 
> > > > > 
> > > > > 
> > > > > -----Ursprüngliche Nachricht-----
> > > > > Von: strk [mailto:strk at keybit.net]
> > > > > Gesendet am: Mittwoch, 15. Oktober 2003 14:58
> > > > > An: PostGIS Users Discussion
> > > > > Betreff: Re: [postgis-users] Dissolve obsolete polygon borders
> > > > > 
> > > > > Try this:
> > > > > 
> > > > > CREATE AGGREGATE unite (
> > > > >         sfunc = GeomUnion,
> > > > >         basetype = geometry,
> > > > >         stype = geometry
> > > > > ); -- this creates an aggregate out of GEOS's geomunion()
> > > > > 
> > > > > -- and this is your query 
> > > > > SELECT your_attribute, unite(the_geom)
> > > > > 	FROM your_table
> > > > > 	GROUP BY your_attribute;
> > > > > 
> > > > > Note that GEOS cvs version is pretty memory absorbing 
> (actually
> > leaking)
> > > > > and probably also buggy. Please let me know whether 
> it worked for
> you.
> > > > > 
> > > > > --strk;
> > > > > 
> > > > > Horst.Duester wrote:
> > > > > > Is there a way to dissolve obsolete borders between 
> polygons with
> > > equal
> > > > > > attributes??
> > > > > >  
> > > > > > I will appreciate your hints.
> > > > > >  
> > > > > > Horst
> > > > > > 
> > > > > > _______________________________________________
> > > > > > postgis-users mailing list
> > > > > > postgis-users at postgis.refractions.net
> > > > > > 
http://postgis.refractions.net/mailman/listinfo/postgis-users
> > > > 
> > > > _______________________________________________
> > > > postgis-users mailing list
> > > > postgis-users at postgis.refractions.net
> > > > http://postgis.refractions.net/mailman/listinfo/postgis-users
> > > > 
> > > > _______________________________________________
> > > > postgis-users mailing list
> > > > postgis-users at postgis.refractions.net
> > > > http://postgis.refractions.net/mailman/listinfo/postgis-users

----- End forwarded message -----

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