I could not find a description about relationship between Geoid and altitude property in Apple's official document that shows its basis:
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?
1- Yes since iPhone 4
2 - Yes
Not from official Apple documentation, from my own experience and customer reports.
Do we know what geoid model this is based off of? I am thinking perhaps EGM96 or a similar geoid since you are saying the calculation is applied worldwide.