Earth Definitions for Land Surveyors

Earth-centered Earth-fixed—A right-handed Cartesian coordinate system whose origin is the Earth’s center of mass. The X-axis runs through the intersection of the equator and zero longitude, the Y-axis runs along a line through the equator and perpendicular to the X-axis, and the Z-axis runs through the International Reference Pole (IRP).

Earth curvature--See curvature of the Earth [SURVEYING].

Earth ellipsoid, mean-1An ellipsoidal body which has the same mass and the same rotational velocity, about the shortest axis as the Earth and the same value of the coefficient C2(-J2) in the representation of the Earth’s gravity potential by the Legendre series. 2An ellipsoidal body whose surface is at constant potential and whose four defining constants are determined by an adjustment of more than four interrelated constants. 3 That ellipsoid which most closely approximates the geoid.

earthwork—1The operations connected with excavations and embankments of earth in preparing foundations of buildings, in constructing canals, railroads, highways, etc. 2 An embankment or construction made of earth.

Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

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