[postgis-devel] EMPTY

[Martin Davis]

One note on your semantics.  I think that

ST_Intersects( empty, empty ) == FALSE

The motivation for this is that EMPTY in the spatial realm is analogous 
to NULL in the SQL realm.  If there's nothing there, you can't determine 
anything about it.

Although really I don't think any of this matters all that much, absent 
any clear use case for using EMPTY.

Paul Ramsey wrote:
> I've started a page on the semantics of empty. Please feel free to add
> cases, clarify and discuss...
>
> http://trac.osgeo.org/postgis/wiki/DevWikiEmptyGeometry
>
> P.
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>   

-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022