Thanks for the feedback st_isvalid identified two crosses in the South of Vietnam - it was a crossing from an unexpected polygon (squeezed in between two provinces, never more than a few metres wide, and masquerading as a province that actually is in the North (of Vietnam). I can only assume that it was an artefact from GRASS, maybe I didn't remove big enough areas.
Steve, There was nothing on the prime meridian / equator boundary, hence my wondering about what the coordinates of the line mean. Thanks again cheers Ben On 15/02/2010, at 22:59 , Stephen Woodbridge wrote: > strk wrote: >> 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. > > You might also check to see if you have same geometries located near the > exception with: > > select * from "table" where > ST_expand(setsrid(makepoint(-0.204257,0.999226),4326), 0.001) && the_geom; > > -Steve W > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
