[postgis-users] connection terminated with buffer(0.0)

[Stefan Zweig]

hi andreas,

recently i had a similar problem. i figured out, that the actual reason was that the buffer(the_geom,0) function seems to crash on polygons which are not closed, i.e. first point != last point, even if only one polygon or one part of a multipolygon is such a not closed on. so it might help you to check whether all the polygons are closed / valid in this the_geom column.

stefan

refer to my postings from august to

An I/O error occured while sending to the backend
and
how to polygonize a not closed linestring?


> -----Ursprüngliche Nachricht-----
> Von: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> Gesendet: 28.08.07 17:17:11
> An: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> Betreff: Re: [postgis-users] connection terminated with buffer(0.0)


> 
> Figure out which geometry is the problem one so (a) you can work  
> around it and (b) you can attach it to a bug report and (c) we can  
> eventually fix it.
> 
> Worst case scenario, binary search by repeatedly cutting your input  
> data set in half.
> 
> P
> 
> On 28-Aug-07, at 5:16 AM, Andreas Laggner wrote:
> 
> > Hello,
> >
> > i used buffer(the_geom, 0.0) several times to repair geometry and  
> > it works good. But now i have a dataset, where problems occur: Any  
> > time i try to repair with buffer the connection to postgresql is  
> > terminated. It seems to relate to one (or more) bad geometry. What  
> > can i do now?
> >
> > My statement (the most simple one without attributes to minimize  
> > possible sources for errors):
> >
> > create table gemeinden_rep();
> > select addgeometrycolumn 
> > ('','gemeinden_rep','the_geom','31467','MULTIPOLYGON',2);
> > alter table gemeinden_rep drop constraint enforce_geotype_the_geom;
> > insert into gemeinden_rep
> >    select buffer(the_geom, 0.0)
> >    from gemeinden;
> >
> >
> > Thanks      Andreas
> >
> >
> >
> > -- 
> >
> > Dipl. Geoökologe Andreas Laggner
> > Institut für Ländliche Räume (LR)
> > Bundesforschungsanstalt für Landwirtschaft (FAL)
> >
> > Institute of Rural Studies
> > Federal Agricultural Research Centre (FAL)
> >
> > Bundesallee 50
> > D-38116 Braunschweig
> >
> > Tel.: (+49) (0)531 596 5515
> > Fax: (+49) (0)531 596 5599
> > E-mail: andreas.laggner at fal.de
> > Homepage: http://www.lr.fal.de/
> > _______________________________________________
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> > postgis-users at postgis.refractions.net
> > http://postgis.refractions.net/mailman/listinfo/postgis-users
> 
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