NAME

GIS::Distance::Cosine - Cosine distance calculations.

SYNOPSIS

my $calc = GIS::Distance::Cosine->new();
my $distance = $calc->distance( $lon1, $lat1 => $lon2, $lat2 );

DESCRIPTION

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

FORMULA

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

AUTHOR

Aran Clary Deltac <bluefeet@cpan.org>

LICENSE

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