[postgis-devel] Polyhedral Surface / Polyhedron /TINS

Paragon Corporation lr at pcorp.us
Wed Jul 9 16:45:25 PDT 2014


I think this is a question for you or Vincent Mora.

I recall you saying there is a bit in the PolyhedralSurface of PostGIS that
denotes if it represents a volume (Polyhedron).  Is that true or was I

Also some other questions what are the rules of validity for Polyhedral
surface and TIN.

I've always assumed that TINs are really a special class of Polyhedral
Surface (one composed of all triangles instead of varying size polygons) and
so the rules that apply to one should be similar to the other.

I'm guessing

1) For both of course the polygon patches and triangles can't overlap

The others not so sure
2) They must share an edge with at lease one other (no islands) -- not sure
if this is true or not?
3) Are they allowed to share the same edge with more than one other polygons
and triangles. I wasn't quite clear from CGAL.  Seemed like it was legal
just a rare occurrence and more representative of a complex polyhedral


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