[postgis-devel] Polyhedral Surface / Polyhedron /TINS

[Oliver Courtin]

Le 11 juil. 2014 à 08:19, Paragon Corporation a écrit :


Regina,

> Do we have a function for setting that bit or is it simply computed it if
> determines the surface is closed?


For now there's not way to set/get this bit from userland,
ant it's current internal usage is dedicated to SFCGAL stuff.

But you're right we could imagine accessors to this SOLID bit,


> I can see cases where people would have a closed surfce but would not want
> it treated as a volume. (similar to closed linestring / polygon)


Could you give us examples about this ?


> Version 1.2.1 I see they do indeed have Polyhedron WKT on LXI (p. 61)
> 
> 
> Polyhedron Z
> (
> ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
> ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
> ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
> ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
> ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
> ((0 0 1, 1 0 1, 1 1 1, 0 1 1. 0 0 1))
> )
> 
> 
> 
> Though oddly on  p (63)
> 
> Where they give the Integer codes for geometric types, the PolyHedron seen
> earlier seems to be mysteriously not present.

Yeah looks definitely like a typo, (Polyhedron instead of PolyhedralSurface in p61)
as the related BNF in LIX refer to PolyhedralSurface,
and PolyhedrelSurface is also use for the integer codes in LXIII and LXIV.

> Which makes me wonder if the earlier WKT was a mistake or the rest of the
> doc was not updted to reflect this new type.

> I ask because Leo was asking why we don't have a Polyhedron type.

We have somehow, it's a closed PolyhedralSurface


O.








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