The elevation of a geographiclocation is its height above a fixed reference point, often the mean sea level. Elevation, or geometric height, is mainly used when referring to points on the Earth\'s surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit.
Less commonly, elevation is measured using the center of the Earth as the reference point. Due to equatorial bulge, there is debate whether the summits of Mt. Everest or Chimborazo are at the higher elevation, as the Chimborazo summit is further from the Earth\'s center while the Mt. Everest summit is higher above mean sea level.
The elevation of a mountain usually refers to its summit. The elevation of a hill also refers to the summit. A valley\'s elevation is usually taken from the lowest point but is often taken all over the valley.
