Golang n-vector library
This performs approximate and exact geodesic calculations using the concept of n-vectors, as described in
Gade, Kenneth, "A Non-Singular Horizontal Position Representation", The Journal of Navigation (2010), 63, 395-417. doi:10.1017/S0373463309990415
See the above or http://www.navlab.net/nvector/ for documentation on the methods used.
Note that in contrast to the above, this library uses a right-handed orthogonal XYZ earth reference frame with Z aligned along the rotation axis, X passing through the Prime Meridian, and Y passing though 90⁰E longitude.