GIS::Distance::Formula::GreatCircle - Great circle distance calculations. (BROKEN)
A true Great Circle Distance calculation. This was created because the GIS::Distance::MathTrig calculation uses Math::Trig's great_circle_distance() which doesn't actually appear to use the actual Great Circle Distance formula.
Normally this module is not used directly. Instead GIS::Distance is used which in turn interfaces with the various formula classes.
As documented in more detail at the BUGS section of GIS::Distance, the distances returned by this module seem to be invalid. Don't use this module unless you want to help fix it.
c = 2 * asin( sqrt( ( sin(( lat1 - lat2 )/2) )**2 + cos( lat1 ) * cos( lat2 ) * ( sin(( lon1 - lon2 )/2) )**2 ) )
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.