haversine.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Program
    {
        public static void Main(String[] args)
        {
            string[] coords = new string[] { "-22.902794,-43.719856", "-22.901263,-43.734494", "-22.906334,-43.719430", "-22.900935,-43.732292", "-22.902794,-43.719856" };
            List<double> distances = new List<double>();

            //var a = (6.372795477598 * Math.Acos(Math.Sin(lata) * Math.Sin(latb) + Math.Cos(lata) * Math.Cos(latb) * Math.Cos(longa - longb)));

            var calc = Haversine.calculate(-22.902794, -43.719856, -22.901263, -43.734494);

            Console.Read();
        }
    }

    public static class Haversine
    {
        public static double calculate(double lat1, double lon1, double lat2, double lon2)
        {
            var R = 6372.8; // In kilometers
            var dLat = toRadians(lat2 - lat1);
            var dLon = toRadians(lon2 - lon1);
            lat1 = toRadians(lat1);
            lat2 = toRadians(lat2);

            var a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) + Math.Sin(dLon / 2) * Math.Sin(dLon / 2) * Math.Cos(lat1) * Math.Cos(lat2);
            var c = 2 * Math.Asin(Math.Sqrt(a));
            return R * c;
        }

        public static double toRadians(double angle)
        {
            return Math.PI * angle / 180.0;
        }
    }
}