My Experience with the Windows Marketplace for Mobile and Windows Mobile 6

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;
using SpeedTracker.Common;

namespace SpeedTracker
{
    class Utility
    {


        public delegate float SpeedConversionDelegate(float sourceSpeed);




        public const double EarthRadiusInMiles = 3956.0;
        public const double EarthRadiusInKilometers = 6367.0;
        public const double EarthRadiusInNauticleMiles = 3437.67;


        public static double ToRadian(double val) { return val * (Math.PI / 180); }
        public static double ToDegree(double val) { return val * 180 / Math.PI; }
        public static double DiffRadian(double val1, double val2) { return ToRadian(val2) - ToRadian(val1); }

        /// <summary> 
        /// Calculate the distance between two geocodes. Defaults to using Miles. 
        /// </summary> 

        /// <summary> 
        /// Calculate the distance between two geocodes. 
        /// </summary> 
        public static double CalcDistance(double lat1, double lng1, double lat2, double lng2, double radius)
        {
            return radius * 2 * Math.Asin(Math.Min(1, Math.Sqrt((Math.Pow(Math.Sin((DiffRadian(lat1, lat2)) / 2.0), 2.0) + Math.Cos(ToRadian(lat1)) * Math.Cos(ToRadian(lat2)) * Math.Pow(Math.Sin((DiffRadian(lng1, lng2)) / 2.0), 2.0)))));
        }

        public static double CalcDistance(Location loc1, Location loc2, DistanceUnit unit)
        {
            double radius=0d;
            switch (unit)
            {
                case DistanceUnit.Kilometers:
                    radius = EarthRadiusInKilometers;
                    break;
                case DistanceUnit.Miles:
                    radius = EarthRadiusInNauticleMiles;
                    break;
                case DistanceUnit.Knots:
                    radius = EarthRadiusInNauticleMiles;
                    break;
            }
            return CalcDistance(loc1.Latitude, loc1.Longitude, loc2.Latitude, loc2.Longitude, radius);
        }

        public static double CalcSpeed(Location loc1, Location loc2, DistanceUnit unit)
        {
            double distance = CalcDistance(loc1, loc2, unit);
            var ts = loc1.TimeStamp.Subtract(loc2.TimeStamp);
            return Math.Abs(distance/ts.TotalHours);
        }


        public static float KnotsToMph(float knots)
        {
            return knots*1.15077945f;
        }

        public static float KnotsToKmph(float knots)
        {
            return knots*1.852f;
        }

        public static float NoConversion(float knots)
        {
            return knots;
        }


    }
}