Aran Clary Deltac >
GIS-Distance-0.08 >
GIS::Distance::Formula::GreatCircle

Module Version: 0.08
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 <bluefeet@cpan.org>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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