GIS::Distance::Polar - Polar coordinate flat-earth distance calculations.
Supposedly this is a formula to better calculate distances at the poles.
While implemented, this formula has not been tested much. If you use it PLEASE share your results with the author. I've tested the results of this formula versus GIS::Distance::Vincenty and it appears that this formula is broken (or the implementation is) as you can see in
A faster (XS) version of this formula is available as GIS::Distance::Fast::Polar.
Normally this module is not used directly. Instead GIS::Distance is used which in turn interfaces with the various formula classes.
a = pi/2 - lat1 b = pi/2 - lat2 c = sqrt( a^2 + b^2 - 2 * a * b * cos(lon2 - lon1) ) d = R * c