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Distances and bearings
There are two sets of formulas for computing distances and bearings
that the user may choose
- the so-called Law of Cosines for Spherical Trigonometry, that is
not very accurate but is quite fast, and
- the modified Rainsford's Method with Helmert's elliptical terms
with a high degree of accuracy but slower; this method cannot be
applied if one of the points is a geographical pole, in which case
GPSMan applies the Law of Cosines.
In some situations, namely when computing the total distance
along a track having very small distances between consecutive points,
the Law of Cosines will yield results with large errors and therefore
it should only be used on very slow computers.
Bearings in GPSMan are always geographic (True North).
GPSMan User Manual
Copyright 1998-2013 Miguel
Filgueiras, 
GPSMan User Manual and the GPSMan logo images by Miguel Filgueiras are licensed under a Creative
Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
