[Proj] triaxial ellipsoid

[Charles Karney]

On 2012-10-17 11:25, Aleksander Yanovskiy wrote:
> Greetings!
>
> Could you please suggest me a software library that can calculate distances on the surface of the triaxial Earth ellipsoid ?
>

Jean-Marc Baillard has coded up Jacobi's solution for geodesics on a
triaxial ellipsoid for an HP-41 calculator, see

   http://hp41programs.yolasite.com/geod3axial.php

I've also written up some notes on the problem which may be of interest

   http://geographiclib.sourceforge.net/1.29/triaxial.html

Disclaimer: A triaxial ellipsoid approximates the earth only slightly
better than an ellipsoid of revolution. If you are really considering
measuring distances on the earth using a triaxial ellipsoid, you should
also be worrying about the shape of the geoid (which essentially makes
the geodesic problem a hopeless mess).