GeographicLib is a small set of C++ classes for performing conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates,for gravity (e.g., EGM2008), geoid height and geomagnetic field (e.g., WMM2020) calculations, and for solving geodesic problems.
GeographicLib.NET...
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A professional geodetic calculation libary about coordinate system's definition, conversion, projection, transformation functions of geodetic datum such as ITRF, WGS84, BDCS, ETRS, etc.
This is a C# .net standard class library containing some professional geodetic algorithms on ellipsoid...
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Geodesy: Functions to calculate distances on spheres (haversine) and ellipsoids (Vicenty). This is because in UWP there are no built-in functions for computing map distance.