[postgis-users] st_union exception

Mark Mitchell mark81 at gmail.com
Thu Jan 15 09:38:20 PST 2009

Anyone get an error similar to this when unioning a bunch of polygons
with st_union?

NOTICE:  TopologyException: no outgoing dirEdge found (-149.073,61.6101,61.6101)
ERROR:  GEOS union() threw an error!

I must say before I get into the details only a few of you will read
that portion that I've used postgis for a while now (since 1.1.5) and
it is *PHENOMENAL*.  I don't want my only posts to this list in that
time frame to be negative -- can't tell you how much
faster/better/intuitive I've found postgis over very expensive
commercial alternatives :-).

My query is similar to the following:

SELECT st_multi(st_union(poly)) from (select ... (a bunch of polys) ... ) a;

The subselect is operating on a fairly dynamic table, and I've gone
months without any problems (with many different sets of polygons too)

I tried st_isvalid() on all polygons returned from the subselect, and
all are valid, and are all non-null...
If I have duplicate (or close to duplicate) polygons returned, is that
going to potentially screw up st_union()?

I'm running Ubuntu server (x64) 8.04 LTS, and am using the packages
for GEOS and postgis from their universe repo:

postgis 1.3.3
libgeos 2.2.3

(postgresql 8.3)

Thanks for the help!


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