4
votes
2answers
701 views

Why are self-intersecting polygons bad?

Working with both ArcGIS and Oracle Spatial, a self-intersecting polygon renders a geometry invalid. Why are self-intersecting polygons a problem?
9
votes
3answers
344 views

Invalid geometry zoo

Many a time and oft I've spent hours struggling with bizarre bugs resulting from invalid geometries. The symptoms vary greatly, including: Database slowdowns Incorrect\Null query results Log files ...
9
votes
2answers
967 views

What are the implications of invalid geometries

I've imported some data in a Postgis database and some of the geometries are reported invalid (ST_IsValidReason reports self-intersection or ring self-intersection). The queries I am performing don't ...