Distance and Area Calculation Demo

DistanceAreaDemo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Device.Location; // Add Reference

namespace DistanceAreaDemo
{
    class Program {
        static void Main(string[] args){            
            // You can write own distance function too
            // http://www.geodatasource.com/developers/c-sharp
            // but this  demo uses System.Device.Location API
            GeoCoordinate c1 = new GeoCoordinate(36.578581, -118.291994);
            GeoCoordinate c2 = new GeoCoordinate(36.23998, -116.83171);
            double distanceInKm = c1.GetDistanceTo(c2) / 1000;
            Console.WriteLine(distanceInKm + " km");

            //around 3.1 km2 - central park
            double area = GetArea(new GeoCoordinate[]{
                new GeoCoordinate(40.800566,-73.957986),
				new GeoCoordinate(40.797187,-73.949575),
				new GeoCoordinate(40.764951,-73.972921),
				new GeoCoordinate(40.768071,-73.981676),
				new GeoCoordinate(40.800566,-73.957986)
            });
            Console.WriteLine(area/1000 + " km^2");

            // Or maybe ues this
            // https://github.com/suryapratap/GeographicLib
            
           
            Console.ReadKey();
        }

        public static double Rad(double deg){
            return deg * Math.PI / 180.0f;
        }
	// http://gis.stackexchange.com/questions/711/how-can-i-measure-area-from-geographic-coordinates
        public static double GetArea(GeoCoordinate[] coords){
            var area = 0.0;
            var len = coords.Length;
            if (len > 2){
                
                for (var i = 0; i < len - 1; i++){
                    GeoCoordinate p1 = coords[i];
                    GeoCoordinate p2 = coords[i + 1];
                    area += Rad(p2.Longitude - p1.Longitude) * (2 + Math.Sin(Rad(p1.Latitude)) + Math.Sin(Rad(p2.Latitude)));
                }
                area = area * 6378137.0 * 6378137.0 / 2.0;
            }
            return Math.Abs(area);
        }
    }
}