[postgis-users] ST_Insersection problem

G. van Es gves2000 at yahoo.com
Wed Oct 5 00:01:16 PDT 2011

Grazie Sandro,

Indeed SnapToGrid did introduce some invalidities. By removing them as well the query runs fine. Now we have to analyse the geometries which has been excluded and see if we need them or not.

Thank you and others for your thoughts.


From: Sandro Santilli <strk at keybit.net>
To: G. van Es <gves2000 at yahoo.com>; PostGIS Users Discussion <postgis-users at postgis.refractions.net>
Sent: Tuesday, October 4, 2011 3:40 PM
Subject: Re: [postgis-users] ST_Insersection problem

On Tue, Oct 04, 2011 at 05:20:15AM -0700, G. van Es wrote:
> Danke Birgit,
> Good point about the validity of the geometry!  However in my case just by experiment I have deleted all records where st_isvalid(ST_GeomFromEWKT(st_asewkt(the_geom)))='f'
> From the 11mio records a little over 800 where invalid and deleted. 
> Still my original query crashes on:NOTICE:  TopologyException: side location conflict at 129105 515684     ERROR:  GEOS Intersection() threw an error!
> All intersection parameters are like ST_SnapToGrid(the_geom, 0.000001) so that doesn't resolve the issue either. Although it makes some difference on which object the process crashes.
> Any ideas are still very welcome.

Note that ST_SnapToGrid can also introduce invalidities, try ST_IsValid
on the return from ST_SnapToGrid. 


  ()   Free GIS & Flash consultant/developer
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