[geos-devel] Re: [postgis-users] Dissolve obsolete polygon borders

[strk]

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
> > > > > 
> > > > > _______________________________________________
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> > > > > postgis-users at postgis.refractions.net
> > > > > http://postgis.refractions.net/mailman/listinfo/postgis-users
> > > > 
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> > > > 
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