Sines, cosines, and the Haversine formula only get you so far (or approximately close). The Earth is neither flat, nor perfectly spherical, but an oblate sphero

Sines, cosines, and the Haversine formula only get you so far (or approximately close). The Earth is neither flat, nor perfectly spherical, but an oblate spheroid. The coordinate systems referenced in TFA are defined to adapt for this, but in different ways depending on the geospatial application, source data collection, map projection, and other factors. A reusable coordinate dataset will include not just latitude and longitude, but also the reference ellipsoid to which it approximates the Earth's surface, and the direction of North used at the location to calibrate sufficient dimensions to pinpoint relative location. Not in a word, ideal, and thus, TFA.