I have Haversine great circle formula working to calculate distances
across a sphere for a GPS program.
Everyone knows the distance is virtually 2D on the Earth's surface,
and does not account for terrain.
Say I know there is terrain in a given area,
and the user is of higher elevation than where he/she started a track log,
I was thinking of using Pythagoras' theorem to attempt a better
overall distance estimation by taking horizontal land distance,
the difference between start and end elevation, and filling in the
3D distance with Pythagoras' theorem.
I don't mean for it to sound perfect, but should it not be a better approximation of overall distance every time?