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2. Heights
Unless the ellipsoid is made to coincide with the geoid, separations between the surfaces vary, Figure C-5.
Figure C-5 Geocentric Earth Model |
There are three heights at each point, Figure C-6:
- H: Orthometric height; from the geoid to the ground point; elevation determined by leveling from a benchmark
- N: Geoid height; from the ellipsoid to the geoid. Also known as the geoidal height.
- h: Geodetic height; from the ellipsoid to the ground point. Also known as the ellipsoidal height.
Figure C-6 Heights |
The heights are related by Equation C-1.
Equation C-1 |