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GIS::Distance::GreatCircle

NAME

GIS::Distance::GreatCircle - Great circle distance calculations.

DESCRIPTION

A true Great Circle Distance calculation. This was created because the GIS::Distance::MathTrig formula uses Math::Trig’s "great_circle_distance()" which doesn’t actually appear to use the actual Great Circle Distance formula (more likely Cosine).

A faster ( XS ) version of this formula is available as GIS::Distance::Fast::GreatCircle.

Normally this module is not used directly. Instead GIS::Distance is used which in turn interfaces with the various formula classes.

FORMULA

c = 2 * asin( sqrt(
( sin(( lat1 - lat2 )/2) )**2 +
cos( lat1 ) * cos( lat2 ) *
( sin(( lon1 - lon2 )/2) )**2
) )

SUPPORT

See " SUPPORT" in GIS::Distance.

AUTHORS

See " AUTHORS" in GIS::Distance.

LICENSE

See " LICENSE" in GIS::Distance.

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