[PROJ] 3D version of geod.inv/geod.fwd?

[Charles Karney]

No.  There are two issues:

* The problem isn't fully defined.  It's not defined exactly what path
  is supposed to be followed from the source to the destination.

* The math for even is simplest generalization of the geodesic problem,
  namely geodesics on a surface of constant height above the ellipsoid,
  is complex.  (Mathar https://arxiv.org/abs/0711.0642 has got furthest
  on this.)

Alternatives are:

* Decompose the problem into a 2d one (geodesics on the ellipsoid) + 1d
  one (constant change in height along the 2d geodesic).

* Solve the problem in 3d Euclidean space.

Which approach is appropriate to your problem will depend on your
application.

On Mon, Jun 28, 2021 at 10:21 AM Idan Miara <idan at miara.com> wrote:
>
> Hi,
>
> Is there a 3D version of geod.inv/fwd?
> i.e
>
> lon1,lat1,alt1,lon2,lat2,alt2 ->
> azi12,s12,elevation12
>
> lon1,lat1,alt1,azi12,s12,elevation12 -> lon2,lat2,alt2
>
> Kind regards,
> Idan
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-- 
Charles Karney <charles at karney.com>
Princeton, NJ 08540