In the equation h = H + N, what does H stand for?

• A. hourly height
• B. geoidal height
• C. ellipsoid-geoid separation
• D. ellipsoidal height

Answer: (A)

The equation h = H + N splits the ellipsoidal height into two pieces: the height above the geoid and the height of the geoid above or below the ellipsoid. Here, h is the ellipsoidal height, N is the geoid undulation (geoid height), and H is the height measured with respect to the geoid. That means H is the orthometric height, the height above the geoid (often associated with mean sea level).

So, the symbol H stands for orthometric height, the physical height above the geoid. The term “hourly height” doesn’t fit geodetic usage, and the other terms describe N or h rather than H.