[postgis-devel] PostGIS 3D - Points to be discussed

Hugo Mercier hugo.mercier at oslandia.com
Thu Jan 31 14:41:12 PST 2013


Le 31/01/2013 21:39, Nicklas Avén a écrit :
> Hallo Olivier
>
> Interesting things. I cannot say I see at once what it it all means, but
> I have a question.
>
> We were discussing this long time ago, but I don't think I have
> understood yet :-)
>
> In 3D when you talk about a solid. How is that defined. As I remember
> you meant that it is a solid if it is closed. But I think that sounds
> strange. It sounds like a closed linestring have to be a polygon. But it
> dosn't. It can be just a border or just a "closed linestring".
>
> How do we flag that a closed surface is a solid and not just a "skin".
>
> If discussing distances. The distance from the table to the wall might
> be 2 meters. But if the house is to be regarded as a solid it is 0.0
> meters.
>
> I'm I thinking wrong or do we have to expand the 3D type(s) with some
> solid type?
>

Hi,

There is already a solid flag for lwgeom, so you can have closed 
polyhedrals that are not considered as solids.
I also added a ST_MakeSolid in our branch, so we can have solids.

However, a Solid may also have 'holes' (interior shells) as Polygons 
have interior rings. If we want to support this, then yes a solid type 
must be added.

-- 
Hugo Mercier
Oslandia



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