Calculating Distance between two Latitude and Longitude GeoCoordinates
c#, geocoding, latitude-longitude, windows-phone-7
Solution
The GeoCoordinate class (.NET Framework 4 and higher) already has `GetDistanceTo` method.
var sCoord = new GeoCoordinate(sLatitude, sLongitude);
var eCoord = new GeoCoordinate(eLatitude, eLongitude);
return sCoord.GetDistanceTo(eCoord);
The distance is in meters.
You need to reference System.Device.
Problem
I'm calculating the distance between two GeoCoordinates. I'm testing my app against 3-4 other apps. When I'm calculating distance, I tend to get an average of 3.3 miles for my calculation whereas other apps are getting 3.5 miles. It's a big difference for the calculation I'm trying to perform. Are there any good class libraries out there for calculating distance? I'm calculating it like this in C#: ``` public static double Calculate(double sLatitude,double sLongitude, double eLatitude, double eLongitude) { var radiansOverDegrees = (Math.PI / 180.0); var sLatitudeRadians = sLatitude * radiansOverDegrees; var sLongitudeRadians = sLongitude * radiansOverDegrees; var eLatitudeRadians = eLatitude * radiansOverDegrees; var eLongitudeRadians = eLongitude * radiansOverDegrees; var dLongitude = eLongitudeRadians - sLongitudeRadians; var dLatitude = eLatitudeRadians - sLatitudeRadians; var result1 = Math.Pow(Math.Sin(dLatitude / 2.0), 2.0) + Math.Cos(sLatitudeRadians) * Math.Cos(eLatitudeRadians) * Math.Pow(Math.Sin(dLongitude / 2.0), 2.0); // Using 3956 as the number of miles around the earth var result2 = 3956.0 * 2.0 * Math.Atan2(Math.Sqrt(result1), Math.Sqrt(1.0 - result1)); return result2; } ``` What could I be doing wrong? Should I calculate it in km first and then convert to miles?