Re: BUG #2533: PostGIS- envelope function returns wrong results

On Sun, Jul 16, 2006 at 01:11:53PM +0000, Vania Bogorny wrote:
> I would like to report an error with the evelope function in PostGIS (Geos
> library).

PostGIS and GEOS are separate projects from PostgreSQL. Questions
and bug reports should go to their respective mailing lists and
bug trackers.

http://postgis.refractions.net/support/

> According to the OGC, two geometries may only overlap if they are both of
> the same type. I performed a query in PostGIS with 2 objects one polygon and
> on multi-line. using the overlaps operation with the envelope function this
> query returned 71 rows. It should return zero, since polygons and lines may
> cross, an not overlap. Indeed, the crosses operations returns zero rows
> among this objects using the evelope function.

If you report this to the PostGIS project then please provide an
example query that demonstrates the behavior you're seeing. The
PostGIS folks might also want to know what versions of PostGIS and
GEOS you're running.

You mention that you're using envelope() but you don't say how --
are you converting the multilinestring to a polygon with envelope()
and using that polygon as one of the parameters to overlaps()?

--
Michael Fuhr