def to_lat_lon
      k0 = 0.9996
      x  = @e - 500000 # Remove Longitude offset
      y  = @n

      # Set hemisphere (1=Northern, 0=Southern)
      y    -= 10000000.0 unless UTMZones::northern_hemisphere? @zone

      ecc = @ellipsoid.eccentricity
      eccPrimeSquared = (ecc)/(1-ecc)
      m  = y / k0
      mu = m / (@ellipsoid.radius * (1 - ecc / 4 - 3 * ecc ** 2 / 64 - 5 * ecc ** 3 / 256))
      e1 = (1 - Math::sqrt(1 - ecc)) / (1 + Math::sqrt(1 - ecc))
      phi1rad = mu +
        (3 * e1 / 2 - 27 * e1 ** 3 / 32) * Math::sin(2 * mu) +
        (21 * e1 ** 2 / 16 - 55 * e1 ** 4 / 32) * Math::sin(4 * mu) +
        (151 * e1 ** 3 / 96) * Math::sin(6 * mu)
      n1 = @ellipsoid.radius / Math::sqrt(1 - ecc * Math::sin(phi1rad) ** 2)
      t1 = Math::tan(phi1rad) ** 2
      c1 = ecc * Math::cos(phi1rad)**2
      r1 = @ellipsoid.radius * (1 - ecc) / ((1 - ecc * Math::sin(phi1rad) ** 2) ** 1.5)
      d = x / (n1 * k0)
      latitude_rad = phi1rad-
        (n1 * Math::tan(phi1rad) / r1) * (d * d / 2 - 
                                    (5 + 3 * t1 + 10 * c1 - 4 * c1 * c1 - 9 * eccPrimeSquared) * d ** 4 / 24 +
                                    (61 + 90 * t1 + 298 * c1 + 45 * t1 * t1 - 
                                     252 * eccPrimeSquared - 3 * c1 * c1) * d ** 6 / 720)
      latitude_deg = latitude_rad * 180.0 / Math::PI
      lon_tmp = (d - (1 + 2 * t1 + c1) * d ** 3 / 6 +
                   (5 - 2 * c1 + 28 * t1 - 3 * c1 * c1 + 8 * eccPrimeSquared +
                    24 * t1 * t1) * d ** 5 / 120) / Math::cos(phi1rad)
      longitude_deg = UTMZones::lon_origin(@zone) + lon_tmp * 180.0 / Math::PI
      LatLon.new latitude_deg, longitude_deg
    end
def to_lat_lon
      k0 = 0.9996
      x  = @e - 500000 # Remove Longitude offset
      y  = @n

      # Set hemisphere (1=Northern, 0=Southern)
      y    -= 10000000.0 unless UTMZones::northern_hemisphere? @zone

      ecc = @ellipsoid.eccentricity
      eccPrimeSquared = (ecc)/(1-ecc)
      m  = y / k0
      mu = m / (@ellipsoid.radius * (1 - ecc / 4 - 3 * ecc ** 2 / 64 - 5 * ecc ** 3 / 256))
      e1 = (1 - Math::sqrt(1 - ecc)) / (1 + Math::sqrt(1 - ecc))
      phi1rad = mu +
        (3 * e1 / 2 - 27 * e1 ** 3 / 32) * Math::sin(2 * mu) +
        (21 * e1 ** 2 / 16 - 55 * e1 ** 4 / 32) * Math::sin(4 * mu) +
        (151 * e1 ** 3 / 96) * Math::sin(6 * mu)
      n1 = @ellipsoid.radius / Math::sqrt(1 - ecc * Math::sin(phi1rad) ** 2)
      t1 = Math::tan(phi1rad) ** 2
      c1 = ecc * Math::cos(phi1rad)**2
      r1 = @ellipsoid.radius * (1 - ecc) / ((1 - ecc * Math::sin(phi1rad) ** 2) ** 1.5)
      d = x / (n1 * k0)
      latitude_rad = phi1rad-
        (n1 * Math::tan(phi1rad) / r1) * (d * d / 2 - 
                                    (5 + 3 * t1 + 10 * c1 - 4 * c1 * c1 - 9 * eccPrimeSquared) * d ** 4 / 24 +
                                    (61 + 90 * t1 + 298 * c1 + 45 * t1 * t1 - 
                                     252 * eccPrimeSquared - 3 * c1 * c1) * d ** 6 / 720)
      latitude_deg = latitude_rad * 180.0 / Math::PI
      lon_tmp = (d - (1 + 2 * t1 + c1) * d ** 3 / 6 +
                   (5 - 2 * c1 + 28 * t1 - 3 * c1 * c1 + 8 * eccPrimeSquared +
                    24 * t1 * t1) * d ** 5 / 120) / Math::cos(phi1rad)
      longitude_deg = UTMZones::lon_origin(@zone) + lon_tmp * 180.0 / Math::PI
      LatLon.new latitude_deg, longitude_deg
    end
Converts this position into the latitude/longitude coordinate system
 @return [LatLon]