[postgis-devel] ST_Expand unexpected behavior

Obe, Regina robe.dnd at cityofboston.gov
Tue Sep 16 07:06:22 PDT 2008


Mark,
> As a matter of interest, can someone with SQL Server 2008 or Oracle 
> Spatial confirm which datatype is returned for a query of the type 
> "SELECT ST_Extent(col) FROM table"? Is it a geometry of type POLYGON?

SQL Server 2008 as I recall doesn't have any aggregate functions
built-in and I don't see 
STExtent as an option in the extensions package either.

http://www.codeplex.com/sqlspatialtools


I'll be installing SQL Server 2008 RTM probably next week sometime so if
no one else can verify before then, I'll check to verify.

I don't have Oracle spatial/locator so can't test that.  I don't see a
reference to an ST_Extent or Extent function anywhere, so I assume their
equivalent is

SDO_AGGR_MBR 

which sounds to me like a bounding box of some sort.

http://www.spatialdbadvisor.com/oracle_spatial_tips_tricks/55/oracle-loc
ator-vs-enterprise-licensing-the-sdogeom-package


I've cc'd Simon - maybe he can confirm that.

> Yeah, the current situation with functions returning BOX2D and BOX3D 
> geometries is not good :(  In SVN trunk I'd like to work on removing 
> these if possible so that only valid OGC geometries are returned.
Hmm - Why?  I would presume at a certain point we will start supporting
3d geometries more heavily and spatial operators for them and the first
proto would be the BOX3D.  

How would your change affect that?

Thanks,
Regina



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