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lib/Geo/HelmertTransform.pm  view on Meta::CPAN

    $lon = atan2($y, $x);
    
    $p = sqrt($x**2 + $y**2);
    $lat2 = atan2($z, $p);

    my $niter = 0;
    do {
        $lat = $lat2;
        $v = $datum->a() / sqrt(1 - $datum->e2() * sin($lat) ** 2);
        $lat2 = atan2(($z + $datum->e2() * $v * sin($lat)), $p);
        die "exceeded 10000 iterations without converging in Geo::HelmertTransform::xyz_to_geo"
            if (++$niter > 10000);
    } while (abs($lat2 - $lat) > 2e-6); # about 1/10000 mile

    $h = $p / cos($lat) - $v;

    return (rad_to_deg($lat), rad_to_deg($lon), $h);
}

=item convert_datum D1 D2 LAT LON H