Basics of Geodesy for Map Projections

Abstract

Geodesy is a branch of applied mathematics and Earth sciences, the scientific discipline and technology dealing with measurement and representation of Earth, including its gravitational field, in three-dimensional, time-varying space. Geodesy can be divided into applied, physical, geometric, and satellite geodesy and is associated with the fields of photogrammetry, remote sensing, and cartography, because one has to start with measuring in order to produce a map. In other words, a map is the final result of surveying and geodesy. Sphere is often taken as a model of the Earth’s surface. Another model frequently taken for the Earth’s surface is rotational ellipsoid. While determination of the Earth’s figure and size is one of the fundamental tasks of geodesy, map projections include the study of spherical or ellipsoidal transformation from the Earth’s or another planet’s surface model to a two dimensional representation. The chapter deals with basic mathematics of an ellipsoid or a sphere required to understand map projections.