[geos-devel] AW:Dissolve obsolete polygon borders
Martin Davis
mbdavis at VividSolutions.com
Tue Oct 21 12:14:13 EDT 2003
Again, this is almost certainly a robustness issue. Robustness issues typically surface in cases where there is linework in two polygons which is very similar, but not identical. About all you can do is to fix the linework so that the vertices are either identical or further apart.
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: Düster Horst [mailto:Horst.Duester at bd.so.ch]
> Sent: Tuesday, October 21, 2003 9:06 AM
> To: 'geos-devel at geos.refractions.net'
> Subject: [geos-devel] AW:Dissolve obsolete polygon borders
>
>
> strk
>
> I took a look at the point where the conflict is located
> (swiss coordinates)
> and figured out that there is an overlapping area of three
> polygones. The
> group attribute of this polygons have the same value.
>
> Could it be that this constallation causes the error?
>
> Horst
>
> -----Ursprüngliche Nachricht-----
> Von: strk [mailto:strk at keybit.net]
> Gesendet am: Dienstag, 21. Oktober 2003 15:53
> An: geos-devel at geos.refractions.net
> Cc: horst.duester at bd.so.ch
> Betreff: [Horst.Duester at bd.so.ch: AW: [postgis-users]
> Dissolve obsolete
> polygon 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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