[postgis-users] Problem with overlap operator(&&) ?

Frank Koormann frank.koormann at intevation.de
Tue Nov 14 23:55:54 PST 2006

* Rob Tester <robtester at gmail.com> [061114 23:26]:
> I recently (with my install of 1.1.5) have run into something that is 
> puzzling me about the overlaps operator. I have two tables that I am 
> comparing the geometry objects using the following SQL:
> select overlaps(a.wkb_geometry,b.wkb_geometry),a.primaryKey,b.primaryKey 
> from az_cr9 a,az_kz b where a.primaryKey=2203 and b.primaryKey=293546 and 
> a.wkb_geometry&&b.wkb_geometry
> This returns one row:
> f;2203;293546
> My question is how does the overlaps operator return TRUE and the overlaps 
> function return FALSE. In fact the two geometries in question do not close 
> to each other. Is this operator broken?

The operator (&&) is working on the bounding boxes while the overlaps()
function is working on the actual geometries.

Best regards,


Frank Koormann                             <frank.koormann at intevation.de>
 Professional Service around Free Software       (http://intevation.net/)
 FreeGIS Project                                 (http://freegis.org/)
 PostGIS Support     (http://intevation.net/services/gis/postgis.en.html)

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