For a flight visualization simulator I receive height data in mean sea level (MSL). Cesium requires WGS84.
WGS84 = MSL + undulation (https://en.wikipedia.org/wiki/Undulation_of_the_geoid)
Undulation doesn’t vary much over short distances. I periodically look it up on bing services using this code below. This works but it’s only 1 meter precision and it’s complicated by the lack of CORS support.
Has anyone found a better way to get undulation?