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

[Rainer Spittel]

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