[Proj] Geodesic distances away from the ellipsoid

[Jay Hollingsworth]

At the risk of asking a dumb question, do any of the geodesic 
algorithms allow calculation of the geodesic distance if the path is 
not on the ellipsoid? Like in an airplane or satellite whose path 
could be assumed to be a constant height above the ellipsoid?

Or do you have to define an ellipsoid matching the satellite orbit 
and use the normal equations on that ellipsoid? If so, how would you 
define an ellipsoid for a long airplane flight?

I've poked around and nothing has jumped out at me. I assume 
aero-engineers guys figured this out long ago....


Jay Hollingsworth

Seabed Portfolio Manager and
Principal Data Architect
Schlumberger Information Solutions
phone: 713 513 8854 fax: 713 513 2093