[postgis-users] ST_Union (8.4) and TopologyException

[pcreso at pcreso.com]

Hi Simon,

I've found the simplest way, if you don't have too many such instances, is to open the offending table in QGIS, zoom into the specified location, identify & fix the problem manually.

There are a number of possible topological errors which can occur, & this way allows a choice of solution, usually move or delete a point or two, or a hole...

You can do similar things with OpenJUMP & other FOSS GIS tools as well I believe.

Cheers,

  Brent Wood


--- On Wed, 8/5/09, Simon Greener <simon at spatialdbadvisor.com> wrote:

> From: Simon Greener <simon at spatialdbadvisor.com>
> Subject: [postgis-users] ST_Union (8.4) and TopologyException
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Date: Wednesday, August 5, 2009, 11:51 AM
> I have been trying out the new
> ST_Union in 1.4 and have a question.
> 
> I note that, whenever I hit an error like this:
> 
> NOTICE:  TopologyException: found non-noded
> intersection between 5.74214e+006 7.36573e+006, 5.74304e+006
> 7.36666e+006 and 5.74339e+006 7.36629e+006, 5.74304e+006
> 7.36666e+006 5.74304e+006 7.36666e+006
> 
> ST_Union fails to produce a result.
> 
> Is there anything I can do to address this
> TopologyException issue within PostGIS.
> 
> regards
> Simon
> -- 
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