[postgis-devel] Recognizing "kind" of geometry

[strk]

On Sat, Mar 06, 2010 at 10:50:42AM +0100, Olivier Courtin wrote:
> 
> On Mar 6, 2010, at 12:22 AM, strk wrote:
> 
> >On Fri, Mar 05, 2010 at 10:39:21PM +0000, Mateusz Loskot wrote:
> >
> >>Where is problem in determining if a GEOMERYCOLLECTION
> >>is mixed or homogeneous?
> >
> >A collection of areas or points or lines can be rendered
> >as a single layer on a map using a consistent symbology.
> 
> 
> There's a need for something more than
> ST_CollectionExtract  and lwgeom_homogenize ?

If ST_CollectionExtract expected behaviour is to always
return what asked dimension-wise it's enough to extract
what one wants (it suffer from bug #457 currently).

Still, to know what you want, sometimes you need to inspect
an input geometry (say you want a function to return the same
kind of input geom, or null), and ST_Dimension doesn't help
in doing that when the input is a collection.

--strk; 

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