NAME

GIS::Distance::MathTrig - Great cirlce distance calculations using Math::Trig.

SYNOPSIS

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

DESCRIPTION

This formula uses Math::Trig's great_circle_distance function which at this time uses math almost exactly the same as the GIS::Distance::Cosine formula. If you want to use the GIS::Distance::Cosine formula you may find that this module will calculate faster (untested assumption). For some reason this and the Cosine formula return slight differences at very close distances. This formula has the same drawbacks as the Cosine formula.

FORMULA

lat0 = 90 degrees - phi0
lat1 = 90 degrees - phi1
d = R * arccos(cos(lat0) * cos(lat1) * cos(lon1 - lon01) + sin(lat0) * sin(lat1))

As stated in the Math::Trig POD.

METHODS

distance

my $distance = $calc->distance( $lon1, $lat1 => $lon2, $lat2 );

This method accepts two lat/lon sets (in decimal degrees) and returns a Class::Measure::Length object containing the distance between the two points.

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.