[postgis-users] ST_Union (8.4) and TopologyException

[Robert Coup]

On Wed, Aug 5, 2009 at 12:17 PM, Simon Greener
<simon at spatialdbadvisor.com>wrote:

>
> I have had to use ST_Transform as I have found the query even more
> problematic when run against the original geodetic data.


Projections are a very likely cause of topology errors for accurate data...
how was it more problematic for geodetic data - more topology errors?

Does:

SELECT count(*) FROM mytable WHERE (geom IS NOT NULL) AND (NOT
st_isvalid(st_transform(geom,
96687)));

return anything for either of the tables?

Rob :)
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