> The results are ok, but the query is too slow. I tried to applay a GIST and > gtree index but performance did not improve. > By explaining the query I see that the where condition gets the query slow. > Is there a more simple way to check if two poligons have a not null > intersection (they overlap)? > > Is there a kind of index I can use ? If you stored the polygon geometries in the same table, you could use a functional index (give the CREATE INDEX statement a function to evaluate rather than a column). Check the CREATE INDEX page for caveats. Beware that the index would grow with the square of the number of rows if you did it like this. Peter ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate