Enlem boylam uzaklık hesaplama (c#)

 using System;

namespace Falcon.Core.Helpers
{
    public class GeoCalculator
    {
        private static double ToRadians(double degree)
        {
            return (degree * Math.PI) / 180;
        }

        public static double Distance(double latitude1, double latitude2, double longitude1, double longitude2)
        {
            // The math module contains
            // a function named toRadians
            // which converts from degrees
            // to radians.
            longitude1 = ToRadians(longitude1);
            longitude2 = ToRadians(longitude2);
            latitude1 = ToRadians(latitude1);
            latitude2 = ToRadians(latitude2);

            // Haversine formula
            double diffLongitude = longitude2 - longitude1;
            double diffLatitude = latitude2 - latitude1;
            double a = Math.Pow(Math.Sin(diffLatitude / 2), 2) +
                       Math.Cos(latitude1) * Math.Cos(latitude2) *
                       Math.Pow(Math.Sin(diffLongitude / 2), 2);

            double c = 2 * Math.Asin(Math.Sqrt(a));

            // Radius of earth in
            // kilometers. Use 3956
            // for miles
            double r = 6371;

            // calculate the result
            return (c * r);
        }
    }
}