Astronomical and Geodetic Point

a point on the earth’s surface, whose latitude and longitude are determined from geodetic measurements and astronomical observations. An astronomical and geodetic point also determines the azimuthal direction from the point to some terrestrial object. In calculating the longitude, latitude, and azimuth of an astronomical and geodetic point by geodetic measurements, the earth is taken to be a certain ellipsoid of revolution. The differences in the respective values that are obtained from astronomical observations and geodetic measurements indicate the deviation of the earth’s shape from the assumed ellipsoid and permit the determination of the earth’s true shape and dimensions.