JTS/GEOS can sometimes does some internal transformation of geometries
to try and overcome robustness errors. So the coordinates in
TopologyException error messages may not always correspond to the
coordinate system of the input geometries.
Ben Madin wrote:
G'day all,
I have a topology exception with a file I clean up with GRASS and exported back
into PostGIS, which I discovered when I tried to merge provinces into countries:
CREATE TABLE new_country AS
SELECT country::varchar(3), st_union(the_geom) as the_geom
FROM new_prov
GROUP BY country;
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
There is obviously information here on where the problem lies, but my entire
project is in Lat / Long (EPSG:4326) in South East Asia, so I'm guessing this
is not (nor is it on a unit square)
So :
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.
(as an aside, changing the query to st_union(st_buffer(the_geom,0)) let it
through (and it works as I wanted)
cheers
Ben
_______________________________________________
postgis-users mailing list
[email protected]
http://postgis.refractions.net/mailman/listinfo/postgis-users
--
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022
_______________________________________________
postgis-users mailing list
[email protected]
http://postgis.refractions.net/mailman/listinfo/postgis-users
