True Heading

[Darrell McCauley]

Lisa Mcculler (mcculler at vinny.cecer.army.mil ) writes on 16 Jul 93:
>Can you in GRASS not only get the distance between two points but
>also a true <aircraft> heading?  If so, is it an easy process?

It's my understanding, from recent discussion on the programmer's
list, that it is not currently possible to do this (in a general way)
in GRASS programs. If it is, could someone please explain how?