How is orthometric height defined in geodesy?

Orthometric height is specifically defined as the height of a point above the geoid, which is an equipotential surface that represents mean sea level across the globe. This definition is rooted in the principles of geodesy, where the geoid serves as a reference for measuring elevations in a consistent manner that accounts for variations in gravitational forces.

Choosing the geoid as the reference allows for a standard measurement of height that reflects the true shape of the Earth, as opposed to just a flat reference like sea level or arbitrary datums. Therefore, orthometric height provides a practical insight into how far above or below a point is relative to this recognized surface, making it crucial for accurate elevation studies and applications in mapping, surveying, and navigation.

Although other definitions might relate to elevations above sea level or local datums, these do not align with the precise, universally applicable definition provided in the context of geodesy for orthometric height. This focus on the geoid distinguishes orthometric height as a valuable measure that integrates gravitational effects, yielding more accurate results in various engineering and geodetic applications.