Geodesics on an ellipsoid of revolution
  Algorithms for the computation of the forward and inverse geodesic problems for an ellipsoid of revolution are derived. These are accurate to better than 15 nm when applied to the terrestrial ellipsoids. The solutions of other problems involving geodesics (triangulation, projections, maritime boundaries, and polygonal areas) are investigated. 
Charles F. F. Karney (SRI International)
physics.geo-ph physics.comp-ph