[geos-devel] AW:Dissolve obsolete polygon borders

[Düster Horst]

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 -----