This course covers introduction to geodesy, discussions on branches of geodesy; geometry of reference ellipsoids; reference systems and frames; geodetic datums; computations of geodetic positions; reductions of measurements to the ellipsoid; datum transformations and time systems. In addition, its application will be included in the fields of sustainable cities and communities, climate monitoring, life below water, and life on terrestrial ecosystems (SDG 11, 13, 14, and 15).