GeographicLib is a small C++ library for: geodesic and rhumb line calculations; conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates; gravity (e.g., EGM2008) and geomagnetic field (e.g., WMM2020) calculations.
This project exists as a central meeting place for those wishing to share in-house developed applications and tools for local government (and related industries) in Australia.