GIS::Distance::Formula::Cosine - Cosine distance calculations.
Although this formula is mathematically exact, it is unreliable for small distances because the inverse cosine is ill-conditioned.
Normally this module is not used directly. Instead GIS::Distance is used which in turn interfaces with the various formula classes.
a = sin(lat1) * sin(lat2) b = cos(lat1) * cos(lat2) * cos(lon2 - lon1) c = arccos(a + b) d = R * c
This method is called by GIS::Distance's distance() method.
Aran Clary Deltac <email@example.com>
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.