*Manual Reference Pages - * GIS::DISTANCE::FORMULA::MATHTRIG (3)
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### NAME
GIS::Distance::Formula::MathTrig - Great cirlce distance calculations using Math::Trig.
### CONTENTS
### 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.
Normally this module is not used directly. Instead GIS::Distance
is used which in turn interfaces with the various formula classes.
### 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
This method is called by GIS::Distance’s *distance()* method.
### SEE ALSO
GIS::Distanc
Math::Trig
### 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.
*perl v5.20.3* | GIS::DISTANCE::FORMULA::MATHTRIG (3) | *2015-06-11* |
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