Cartesian coordinate systems, applications of Cartesian coordinate transformations in surveying. Mathematical transformations between geodetic, Cartesian and topocentric coordinate systems, ellipsoid geometry, orthometric and ellipsoid height systems. Map projections and ellipsoidal geometry, principles of map projections, surveying and mapping projections, transverse Mercator projection, ellipsoidal computations. Corrections to field observations. Geodetic and astronomical reference systems; the relationship between natural and geodetic reference systems, deflection of the vertical; geoid models and reference ellipsoids, height systems, celestial coordinate systems. Geodetic coordinate systems and datums; definition of AGD, GDA, AHD; the impact of tectonic motion on datum and coordinates; and international systems such as ITRF. The use of GPS/GNSS to define reference frames, as well as providing a means for a surveyor or geospatial engineer to determine coordinates of points in the frame.