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

[Oliver Courtin]

Le 31 janv. 2013 à 21:39, Nicklas Avén a écrit :

Hi Nicklas,

To complete Hugo previous answer,

> 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".

It is a bit strange because (for now) SFS 1.2 use the same type to represent
both surfaces in 3D and also solids (since the surface is closed).

Maybe/surely with coming SFS standard, solids could have distinct WKT 
types. But in the meantime...

> 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?


Nothing to be done related to 3D type, right now (it's already there).
But you're right if some 3D functions are not aware that surfaces 
(Tin / PolyhedralSurface) could also represent solid, 
well it's a missing feature...


O.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-devel/attachments/20130201/149b2b55/attachment.html>