[postgis-users] ST_Union throws TopologyException found non-noded intersection between...

[Mark Cave-Ayland]

On Thursday 03 April 2008 04:05:22 Rainer Spittel wrote:
> Hi,
>
> I have a problem aggregating a parcel multipolygon dataset. I want to
> join all parcel geometries (multipolygon) via their road names. All
> geometries have the same projection and are valid (checked via PostGIS).
>
>
> I am running a sql-statement like:
>
>   select road, suburb, town, tla, ST_UNION(the_geom) as the_geom
>   into locations
>   from property
>   group by road, suburb, town, tla;
>
> and get this error message after a while:
>
> NOTICE:  TopologyException: found non-noded intersection between
> 3.15383e+06 5.67709e+06, 3.15382e+06 5.67704e+06 and 3.15382e+06
> 5.67698e+06, 3.15382e+06 5.67704e+06 3.15382e+06 5.67704e+06
>
> ERROR:  GEOS union() threw an error!
>
>
> To see if I have a general data problem, I reduced the polygon
> complexity to points via ST_POINTONSURFACE, which works fine. But using
> polygons, the statements just fails.
>
> This is the server configuration:
>   OS: Linux Fedora
>   DB: Postgres 8.2.5
>       -> PostGIS 1.3.2
>       -> GEOS 3.0.0 (release version)
>       -> Proj-4.4.9
>
> I run out of ideas and I am looking forward for any help.
> Cheers
>
> Rainer


Hi Rainer,

Have you checked the validity of your polygons using ST_IsValid()?


HTH,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063