Currently the Cesium Ion Asset “Cesium World Terrain” is providing ellipsoid elevations
It would be really nice to have a Cesium Ion orthometric terrain Asset such as:
“Cesium World Terrain EGM96”
allowing viewer.terrainProvider = Cesium.createWorldTerrainEGM96
providing the existing terrain data with the EGM96 Geoid offsets applied, so ocean shorelines are at an elevation of 0
perhaps “Cesium World Terrain EGM2008” but at least EGM96 to help assist in displaying and generating kml on the fly
the terrain example Cesium Sandcastle using Cesium.ArcGISTiledElevationTerrainProvider , returns orthometric elevations, but doesn’t have the performace of the Ion Assets, and the performance in picking detailed elevation information