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GIS::Distance::Haversine

NAME

GIS::Distance::Haversine - Exact spherical distance calculations.

DESCRIPTION

This is the default distance calculation for GIS::Distance as it keeps a good balance between speed and accuracy.

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

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

FORMULA

dlon = lon2 - lon1
dlat = lat2 - lat1
a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2
c = 2 * atan2( sqrt(a), sqrt(1-a) )
d = R * c

SEE ALSO

<http://mathforum.org/library/drmath/view/51879.html>

<http://www.faqs.org/faqs/geography/infosystems-faq/>

SUPPORT

See " SUPPORT" in GIS::Distance.

AUTHORS

See " AUTHORS" in GIS::Distance.

LICENSE

See " LICENSE" in GIS::Distance.

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