[postgis-devel] Weird ST_Intersection behavior

Martin Davis mbdavis at refractions.net
Tue May 25 09:11:36 PDT 2010


The Polygon is not valid - it is "twisted" in the middle.

George Silva wrote:
> Hello guys, I'm not sure this is the right place. I'm getting GEOS
> exceptions while doing simple ST_Intersection calculations.
>
> Check this out:
>
> "POSTGIS="1.4.0" GEOS="3.1.1-CAPI-1.6.0" PROJ="Rel. 4.6.1, 21 August 2008"
> USE_STATS"
>
> SELECT ST_Intersection(
>     ST_GeomFromText('POLYGON((0 0, 1 1, 1 0, 0 1, 0
> 0))'),ST_GeomFromText('LINESTRING(-1 -1, 2 2)'));
>
> NOTICE:  TopologyException: found non-noded intersection between 0 0, 1 1NG
> ( and 1 0, 0.5 0.5 0.5 0.5
> ERROR:  GEOS Intersection() threw an error!
>
> ********** Error **********
>
> ERROR: GEOS Intersection() threw an error!
> SQL state: XX000
>
> Any hints?
>
> Thanks
>
>   
> ------------------------------------------------------------------------
>
> _______________________________________________
> postgis-devel mailing list
> postgis-devel at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-devel
>   

-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022




More information about the postgis-devel mailing list