What is an ellipsoid?

An ellipsoid is defined as a mathematically defined surface that closely approximates the shape of the Earth. It is created by rotating an ellipse around its minor axis and serves as a reference model for geodetic applications. The Earth's shape is not a perfect sphere; rather, it is slightly flattened at the poles and bulging at the equator due to its rotation. This oblate spheroid model is essential in geodesy because it allows for accurate calculations and measurements of geographic locations and distances on the Earth's surface.

The significance of the ellipsoid in geodetic engineering cannot be overstated, as it is used in mapping, GPS technology, and many surveying practices. The ellipsoid parameters, such as the semi-major and semi-minor axes, provide a standardized framework that enables consistent and precise geospatial data analysis across different geographic areas and applications.