public static function qsfnz($eccent, $sinphi)
    {
        if ($eccent > 1.0e-7) {
            $con = $eccent * $sinphi;

            return (
                ( 1.0 - $eccent * $eccent)
                * ($sinphi / (1.0 - $con * $con) - (.5 / $eccent) * log( (1.0 - $con) / (1.0 + $con) ))
            );
        }

        return (2.0 * $sinphi);
    }