[postgis-users] Finding a TopologyException

[strk]

On Mon, Feb 15, 2010 at 03:51:40PM +0800, Ben Madin wrote:

> NOTICE:  TopologyException: found non-noded intersection between LINESTRING (-0.204257 0.999226, -0.204257 0.99858) and LINESTRING (-0.204257 0.995743, -0.204257 0.999226) at -0.204257 0.999226

> How does the coordinates returned by the error relate to my geometry? or What do they mean? Can I use this information to find the problem part of the geometry.

Often such problems are due to invalid geometries in input.
What you could do is:
	SELECT gid, ST_isValidReason(the_geom) where NOT ST_isValid(the_geom);

That should give you more usable informations.
Even better, the trunk version of postgis has an ST_isValidDetail which also
gives you the problematic point as a Geometry.

--strk;

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