dvdoug / PHPCoord

     * "A Guide to Coordinate Systems in Great Britain"

     * @return LatLng

     */

    public function toOSGB36(): LatLng

    {

        if ($this->refEll == RefEll::airy1830()) {

            return $this;

        }

        $asWGS84 = $this->toWGS84();

        $tx = -446.448;

        $ty = 125.157;

        $tz = -542.060;

        $s = 0.0000204894;

        $rx = deg2rad(-0.1502 / 3600);

        $ry = deg2rad(-0.2470 / 3600);

        $rz = deg2rad(-0.8421 / 3600);

        return $asWGS84->transformDatum(RefEll::airy1830(), $tx, $ty, $tz, $s, $rx, $ry, $rz);

    }

    /**

     * Convert this LatLng object to ED50 datum.

     * "Making maps compatible with GPS"

     * @return LatLng

     */

    public function toIreland1975(): LatLng

    {

        if ($this->refEll == RefEll::airyModified()) {

            return $this;

        }

        $asWGS84 = $this->toWGS84();

        $tx = -482.530;

        $ty = 130.596;

        $tz = -564.557;

        $s = -0.00000815;

        $rx = deg2rad(-1.042 / 3600);

        $ry = deg2rad(-0.214 / 3600);

        $rz = deg2rad(-0.631 / 3600);

        return $asWGS84->transformDatum(RefEll::airyModified(), $tx, $ty, $tz, $s, $rx, $ry, $rz);

    }

    /**

     * Convert this LatLng object to WGS84 datum