Series of elevation design in AutoCAD

The elevation of a geographic location belongs to its height over or underneath a fixed reference point, generally a reference geoid, a mathematical model of the Earth�s sea level similar to equipotential gravitational surface.

Elevation, or geometric height, is primarily applied while referring to points on the Earth�s surface, whereas altitude or geopotential height is applied for points over the surface, like an aircraft in flight or a spacecraft in orbit, and depth is applied for points underneath the surface.

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