Aran Clary Deltac >
GIS-Distance-0.09 >
GIS::Distance::Formula::Cosine

Module Version: 0.09
GIS::Distance::Formula::Cosine - Cosine distance calculations.

Although this formula is mathematically exact, it is unreliable for small distances because the inverse cosine is ill-conditioned.

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

a = sin(lat1) * sin(lat2) b = cos(lat1) * cos(lat2) * cos(lon2 - lon1) c = arccos(a + b) d = R * c

This method is called by GIS::Distance's distance() method.

GIS::Distance::Formula::Cosine::Fast

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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