TopologyExceptions are thrown when the topological graph GEOS uses to compute relationships enters an invalid or impossible state. There are two reasons for TopologyExceptions to be thrown:

  1. GEOS is handling a valid geometry case incorrectly. That is, a bug.
  2. GEOS is handling an invalid geometry case correctly.

Before submitting a bug ticket based on TopologyExceptions, ensure your geometries are valid, by running the IsValid? method on them. In PostGIS, the ST_IsValid() function calls the appropriate GEOS test. If your geometries are invalid, the problem is with your geometry, not with GEOS.

Last modified 12 years ago Last modified on Dec 12, 2007 10:00:47 AM