[postgis-users] problem with intersection

[Gregory S. Williamson]

>Hi, Olivier,
>
>olivier dorie schrieb:
>
>> I'm using PostgreSQL 7.4.6 with Postgis 0.9.0 and geos 2.1.0.
>>  
>> When I intersect the 2 following polygons, the answer is an exception :
>>=================================================================================================
>> select intersection('POLYGON((588912.7 2432104.5,588927.7 2432124,
>> 588928.9 2432123.6, 588923.7 2432132.3,588912.7
>> 2432104.5))','POLYGON((588916.4 2432124.4, 588920.7 2432129.9,588928.6
>> 2432123.7,588930.1 2432122.6,588916.4 2432124.4))');
>> NOTICE:  TopologyException: no outgoing dirEdge found (588929,2.43212e+06)
>> ERREUR:  GEOS Intersection() threw an error!
>> >>=================================================================================================
>> I think the polygons are valid. is there a problem with the intersection
>> or in my installation ?
>
>Hmm, isvalid() returns true for both polygons in my installation, and I
>get the same error on intersection, so I think you possibly found a bug.
>
>Markus

We've seen something similar in our runtimes ... we see a large # of these "no outgoing edge" errors from polygons which are themseleves valid. I haven't been able to get a simple example, but I have the feeling its the same issue.

I can try sleuthing logs more if that owuld help, but our examples would not be a clean as the submitted test case.

Greg WIlliamson
DBA
GlobeXplorer LLC