Geo::Forward - Calculate geographic location from lat, lon, distance, and heading.
use Geo::Forward; my $obj = Geo::Forward->new(); # default "WGS84" my ($lat1,$lon1,$faz,$dist)=(38.871022, -77.055874, 62.888507083, 4565.6854); my ($lat2,$lon2,$baz) = $obj->forward($lat1,$lon1,$faz,$dist); print "Input Lat: $lat1 Lon: $lon1\n"; print "Input Forward Azimuth: $faz\n"; print "Input Distance: $dist\n"; print "Output Lat: $lat2 Lon: $lon2\n"; print "Output Back Azimuth: $baz\n";
This module is a pure Perl port of the NGS program in the public domain "forward" by Robert (Sid) Safford and Stephen J. Frakes.
The new() constructor may be called with any parameter that is appropriate to the ellipsoid method which establishes the ellipsoid.
my $obj = Geo::Forward->new(); # default "WGS84"
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
$obj->ellipsoid({a=>1}); #Custom Sphere 1 unit radius
This method is the user frontend to the mathematics. This interface will not change in future versions.
my ($lat2,$lon2,$baz) = $obj->forward($lat1,$lon1,$faz,$dist);
Note: Latitude and longitude units are signed decimal degrees. The distance units are based on the ellipsoid semi-major axis which is meters for WGS-84. The forward and backward azimuths units are signed degrees clockwise from North.
Add tests for more ellipsoids.
Please log on RT and email to the geo-perl email list as well as the author.
DavisNetworks.com supports all Perl applications including this package.
No guarantees that Perl handles all of the double precision calculations in the same manner as Fortran.
Michael R. Davis qw/perl michaelrdavis com/ CPAN ID: MRDVT
Copyright (c) 2011 Michael R. Davis (mrdvt92)
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
