C# - Entfernung zwischen zwei geografischen Koordinaten berechnen

static class DistanceCalculator
{
	/// <summary>
	/// Gets the distance between two points.
	/// </summary>
	/// <param name="latitude1">The latitude1.</param>
	/// <param name="longitude1">The longitude1.</param>
	/// <param name="latitude2">The latitude2.</param>
	/// <param name="longitude2">The longitude2.</param>
	/// <returns></returns>
	public static double GetDistanceBetweenTwoPoints(double latitude1, double longitude1, double latitude2, double longitude2)
	{
		double theta = longitude1 - longitude2;
		double distance = Math.Sin(ConvertDecimalDegreesToRadians(latitude1)) *
						  Math.Sin(ConvertDecimalDegreesToRadians(latitude2)) + 
						  Math.Cos(ConvertDecimalDegreesToRadians(latitude1)) * 
						  Math.Cos(ConvertDecimalDegreesToRadians(latitude2)) *
						  Math.Cos(ConvertDecimalDegreesToRadians(theta));
						  
		distance = Math.Acos(distance);
		distance = ConvertRadiansToDecimalDegrees(distance);
		distance = distance * 60 * 1.1515;
		// convert to kilometers
		return distance * 1.609344;
	}

	/// <summary>
	/// Converts the decimal degrees to radians.
	/// </summary>
	/// <param name="degree">The degree.</param>
	/// <returns></returns>
	private static double ConvertDecimalDegreesToRadians(double degree)
	{
		return (degree * Math.PI / 180.0);
	}

	/// <summary>
	/// Converts the radians to decimal degrees.
	/// </summary>
	/// <param name="radian">The radian.</param>
	/// <returns></returns>
	private static double ConvertRadiansToDecimalDegrees(double radian)
	{
		return (radian / Math.PI * 180.0);
	}
}