NAME

       Geo::Inverse - Calculate geographic distance from a lat & lon pair.

SYNOPSIS

         use Geo::Inverse;
         my $obj = Geo::Inverse->new(); # default "WGS84"
         my ($lat1,$lon1,$lat2,$lon2)=(38.87, -77.05, 38.95, -77.23);
         my ($faz, $baz, $dist)=$obj->inverse($lat1,$lon1,$lat2,$lon2); #array context
         my $dist=$obj->inverse($lat1,$lon1,$lat2,$lon2);              #scalar context
         print "Input Lat: $lat1  Lon: $lon1\n";
         print "Input Lat: $lat2 Lon: $lon2\n";
         print "Output Distance: $dist\n";
         print "Output Forward Azimuth: $faz\n";
         print "Output Back Azimuth: $baz\n";

DESCRIPTION

       This module is a pure Perl port of the NGS program in the public domain "inverse" by
       Robert (Sid) Safford and Stephen J. Frakes.

CONSTRUCTOR

   new
       The new() constructor may be called with any parameter that is appropriate to the
       ellipsoid method which establishes the ellipsoid.

         my $obj = Geo::Inverse->new(); # default "WGS84"

METHODS

   ellipsoid
       Method to set or retrieve the current ellipsoid object.  The ellipsoid is a
       Geo::Ellipsoids object.

         my $ellipsoid=$obj->ellipsoid;  #Default is WGS84

         $obj->ellipsoid('Clarke 1866'); #Built in ellipsoids from Geo::Ellipsoids
         $obj->ellipsoid({a=>1});        #Custom Sphere 1 unit radius

   inverse
       This method is the user frontend to the mathematics. This interface will not change in
       future versions.

         my ($faz, $baz, $dist)=$obj->inverse($lat1,$lon1,$lat2,$lon2);

TODO

       Add more tests.

BUGS

       Please send to the geo-perl email list.

LIMITS

       No guarantees that Perl handles all of the double precision calculations in the same
       manner as Fortran.

AUTHOR

       Michael R. Davis qw/perl michaelrdavis com/

LICENSE

       Copyright (c) 2006 Michael R. Davis (mrdvt92)

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

SEE ALSO

       Net::GPSD Geo::Ellipsoid GIS::Distance::GeoEllipsoid