[PROJ] geoid model from a geographic 2D

[Greg Troxel]

Javier Jimenez Shaw via PROJ <proj at lists.osgeo.org> writes:

> I am trying to add a geoid model for Singapore to my proj.db.
> The problem is that the "source crs", SVY21 (EPSG:4757), is only defined as
> Geographic 2D in EPSG
> https://spatialreference.org/ref/?search=SVY21

What does it mean to have a geoid model for a 2D CRS?

It looks like the model is for SVY21 to some national orthometric height.

Is it that the CRS SVY21, is in reality a lat/lon/HAE system, but that
it is miscoded in EPSG as 2D (or only the projection to 2D is listed)?

Do you in fact have HAE that are in SVY21?


All that said, manually loading a CRS into your DB that is what
"Singapore Geodetic Survey" should have asked EPSG to add, makes sense
to me.