private double computeRho(double lat) {
    return earth_radius * Math.sqrt(C - 2 * n * Math.sin(lat)) / n;
  }
private double computeRho(double lat) {
    return earth_radius * Math.sqrt(C - 2 * n * Math.sin(lat)) / n;
  }
private double computeRho ( double lat ) { return earth_radius * Math . sqrt ( C - 2 * n * Math . sin ( lat ) ) / n ; }
Compute the RHO parameter

@param lat latitude
@return the rho parameter
Compute the RHO parameter