[postgis-devel] LWGEOM for PostGIS 2.0

[Olivier Courtin]

On Sep 5, 2010, at 8:16 PM, Paul Ramsey wrote:

> Is vertical datum a separate concern from CRS? Or is a CRS a compound
> element including vertical datum, horizontal datum, and projection?

There's two uses case, AFAIK:

1)  3D geocentric or 3D geographic (for instance EPSG:4327)
       where a single CRS deal with 3D axis

2) A Compound of a 'classical' 2D horizontal CRS, and an additional
      vertical one (for instance EPSG:4326 + EPSG:5773)


For information, Oracle handle it with an HSRID and an VSRID.

> I was thinking that we will use GBOX for the box when we update
> LWGEOM, so cover all our dimensional bases. The idea is to upgrade
> LWGEOM just enough to mesh with the GSERIALIZED form used by
> geography, and flip geometry over to use GSERIALIZED with it.

Ok that's a good point, i update the Wiki page with GBOX instead

> The question of whether vertical datum needs separate storage ceases
> to be academic if we need to serialize it separately. Do we?

--
Olivier