[postgis-devel] Can a PolyhedralSurface/TIN be an element of MultiSurface ?

Olivier Courtin olivier.courtin at oslandia.com
Sun Jul 24 10:14:26 PDT 2016

Even, Paul,

Summer lag time…

> I wouldn't look at our BNFs as anything particularly authoritative, they were mostly transcribed from the ISO SQL specs, if I recall correctly. And at the time they were written (maybe) still, those specs didn't have anything to say about TIN or POLYHEDRALSURFACE. Those types were added later, and Olivier is the one to comment on where he got the info from on how to add them to the heirarchy. Since we don't really care much about the object heirarchy internal to postgis (the only thing we really care about is "are you a collection or not") any details of child/parent relationships are not really important to us.

And yes, for PostGIS. we took OGC SFS 1.2 as implementation reference.

And so implied that a TIN or PS can’t have interior ring, for instance.
But only one exterior one.

I thought that was the main reason for surface / multi surface hierarchy stuff.



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