Surface shape types.
| Member | Value | Description | 
|---|---|---|
| eCrdnReferenceShapeEllipsoid | 1 | An ellipsoid reference shape as defined by the central body (by default, it is WSG84). | 
| eCrdnReferenceShapeTerrain | 2 | Terrain as the terrain reference. | 
| eCrdnReferenceShapeMSL | 3 | Mean Sea Level as the terrain reference. | 





