Geographic library
GeographicLib is a small set of C classes for performing conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates and for solving geodesic problems. The emphasis is on returning accurate results with errors close to round-off (about 5–15 nm). In addition, various properties of the Transverse Mercator Projection are described and an accurate algorithm for Geodesics on the Ellipsoid is given.

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