[postgis-users] Union as an aggregate

Paul Ramsey pramsey at refractions.net
Mon Sep 29 09:35:17 PDT 2003

strk wrote:

> Hello, I'm playing around with GEOS and I wondered why
> there is no aggregate function to use with GEOSUnion.

No reason. It is relatively simple to code up in a dumbass way. Doing it 
efficiently is much harder.

> I think an aggregate would be the most natural way to
> use it (does OGC talks about this?).

I agree, it is the way most people will understand union to work. Of 
course, OGC makes no mention of such an operating mode at all.


      | Paul Ramsey
      | Refractions Research
      | Email: pramsey at refractions.net
      | Phone: (250) 885-0632

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