Geodesy

That branch of applied mathematics which determines, by means of observations and measurements, the figures and areas of large portions of the earth's surface, or the general figure and dimenshions of the earth; or that branch of surveying in which the curvature of the earth is taken into account, as in the surveys of States, or of long lines of coast.

the branch of geology that studies the shape of the earth and the determination of the exact position of geographical points