Calculate the target point by using initial coordinate, bearing angle and distance

Question

I need to calculate the target coordinate by using the initial coordinate, bearing angle and distance. I came across this on how to calculate it. Then I construct the code in C#, but it seems I can't get exact location correctly. I use below code this my answer:

Target latitude :6.34374176458679
Target longitude : 206.297566445544

When I use the application from the website i mention it get this:

Destination point:  03° 10′ 28″ N, 103° 08′ 15″ E /Lat:3.174444° Lon:103.150833°
Final bearing:  040° 24′ 37″

That are most accurate. Has anybody used this kind of method?

EDIT:

        //bearing angle 
        double rad = 40.41;
        rad *= Math.PI / 180;

        //angDist = distance/radius
        double angDist = 0.717 / 6371;

        Console.WriteLine("Angular distance:" + angDist);

        double latitude =  3.169416;
        double longitude = 103.146690;

        latitude *= Math.PI / 180;
        longitude *= Math.PI / 180;

        double lat2 = Math.Asin(Math.Sin(latitude)*Math.Cos(angDist)+Math.Cos(latitude)*Math.Sin(angDist)*Math.Cos(rad));

        double forAtana = Math.Sin(rad) * Math.Sin(angDist) * Math.Cos(latitude);
        double forAtanb = Math.Cos(angDist)-Math.Sin(latitude)*Math.Sin(lat2);

        double lon2 = longitude + Math.Atan2(forAtana,forAtanb);


        double finalLat = latitude + lat2;
        double finalLon = longitude + lon2;

        finalLat *=  180 / Math.PI;
        finalLon *=  180 / Math.PI;

        Console.WriteLine("Target latitude :" + finalLat);

        Console.WriteLine("Target longitude : " + finalLon);

        // supposely final answer should be Lat:3.174444° Lon:103.150833° (using the movable-type website)


        Console.ReadKey();

Answer 1

I think that you are adding lat1 (decimal degrees) + lat2 (radians).

lat2 and lon2 are final latitude and longitude in radians. Just convert them to degrees.

UPDATE: I don't know the language, but must to be something like:

double finalLat = lat2 * 180 / Math.PI;  
double finalLon = lon2 * 180 / Math.PI;

Console.WriteLine("Target latitude : " + finalLat); 
Console.WriteLine("Target longitude : " + finalLon); 

---

(Also, they are using Radius = 6371 km.)

Answer 2

This final code that will get the target point by using initial coordinate, bearing angle to target point and distance. I get this reference from this website.

        double rad = 64.10;
        rad *= Math.PI / 180;

        double angDist = 0.343 / 6371;

        Console.WriteLine("Angular distance:" + angDist);

        double latitude =   3.170620;
        double longitude = 103.151279;

        latitude *= Math.PI / 180;
        longitude *= Math.PI / 180;

        double lat2 = Math.Asin(Math.Sin(latitude)*Math.Cos(angDist)+Math.Cos(latitude)*Math.Sin(angDist)*Math.Cos(rad));

        double forAtana = Math.Sin(rad) * Math.Sin(angDist) * Math.Cos(latitude);
        double forAtanb = Math.Cos(angDist)-Math.Sin(latitude)*Math.Sin(lat2);

        double lon2 = longitude + Math.Atan2(forAtana,forAtanb);


        //double finalLat = latitude + lat2;
        //double finalLon = longitude + lon2;

        lat2 *=  180 / Math.PI;
        lon2 *=  180 / Math.PI;

        Console.WriteLine("Target latitude :" + lat2);

        Console.WriteLine("Target longitude : " + lon2);



        Console.ReadKey();