[Gdal-dev] Recommendations for vertical data in GDAL

[Frank Warmerdam]

Ray Gardener wrote:
> Antoine Hue wrote:
> 
>  > Without being an expert in this field, I have run into some of these 
> issues while working on 3D terrain modeling from DEM. I fully support an 
> initiative to make it more explicit that a layer is a DEM, what is the 
> unit and pixel interpretation.
>  >
>  > An extension to this is support for geocentric SRS and warp to/from 
> geocentric SRS.
> 
> I think that could be satisifed by
> a) having ORGSpatialRef parse GEOCCS nodes (if it doesn't already),

Ray,

Well, I think they will parse ok now because the parser doesn't
really look at what kinds of nodes it is parsing.

> b) adding an IsGeocentric() method,

agreed.

> c) adding a SetGeocentricCS() method,

agreed.

> b) doing any necessary mods to OGRCoordTransform to use such data when 
> one or both of its spatialrefs are geocentric, and

PROJ.4 already supports geocentric coordinate systems.  So I think we
would just have to update the to/from PROJ.4 format translation code
to support geocentric.

> c) formalizing the list of avail. geocentric datums.

Hmm, I'm not clear on what a geocentric datum is.

Best regards,
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