[postgis-users] GeomUnion Bug?

[Martin Davis]

Charlie Savage wrote:
>
> However, is this another bug then?
>
> select astext(extent(GeomFromText('POINT(-104 40)')))
>
> "POLYGON((-104 40,-104 40,-104 40,-104 40,-104 40))"
Looks like the same bug/design issue.  JTS would return the envelope as 
a POINT in this case.
>
>
> But luckily, this actually works:
>
> select astext(extent(collect(envelope(GeomFromText('POINT(-104 40)')), 
> envelope(GeomFromText('POINT(-105 39)')))))
>
> "POLYGON((-105 39,-105 40,-104 40,-104 39,-105 39))"
>
> So that solves my issue.
Yeah, the good news is that envelope operations can be pretty 
insensitive to geometry validity, so they should always be able to 
return appropriate answers.
>
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-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022