ST_PointOnSurface returns point on the boundary of the polygon -------------------------------------------------------------- Key: TEIID-4580 URL: https://issues.jboss.org/browse/TEIID-4580 Project: Teiid Issue Type: Bug Components: Query Engine Affects Versions: 9.x, 8.12.7.6_3 Reporter: Andrej Šmigala Assignee: Steven Hawkins Fix For: 9.2, 9.1.2 Calling ST_PointOnSurface with a polygon argument returns one of the points of the polygon boundary. E.g. {code:sql} SELECT ST_AsText(ST_PointOnSurface(ST_GeomFromText('POLYGON ((67 13, 67 18, 59 18, 59 13, 67 13))'))); {code} returns {{POINT (67 13)}} The spec says bq. PointOnSurface( ):Point—A point guaranteed to be on this Surface. which might not be completely clear, but [several|http://gis.stackexchange.com/questions/76498/how-is-st-pointonsur...] [sources|http://workshops.boundlessgeo.com/postgis-intro/geometry_returnin...] indicate that "on this surface" means _inside_ the surface. When running the same query against a postgis instance (not through teiid), the result is {{POINT(63 15.5)}}, which is actually inside the polygon.