I could not find a description about relationship between Geoid and altitude property in Apple's official document that shows its basis:
https://developer.apple.com/documentation/corelocation/cllocation/1423820-altitude
I have two following questions:
1. Is the value returned by the altitude property of CoreLocation calculated from Geoid?
2. (If 1.'s answers YES, ) Does altitude including Geoid apply to any location all over the world?