/// <summary>
/// Returns new geodetic coordinate in radians
/// </summary>
/// <param name="lat1">Latitude in radians</param>
/// <param name="lon1">Longitude in radians</param>
/// <param name="crs12">Bearing</param>
/// <param name="d12">Distance</param>
/// <returns>double[]</returns>
public static double[] Direct(double lat1, double lon1, double crs12, double d12)
{
lon1 *= -1; //REVERSE LONG FOR CALC 2.1.1.1
var EPS = 0.00000000005; //Used to determine if near pole.
double dlon, lat, lon;
d12 = d12 * 0.0005399565; //convert meter to nm
d12 = d12 / (180 * 60 / Math.PI); //Convert to Radian
//Determine if near pole
if ((Math.Abs(Math.Cos(lat1)) < EPS) && !(Math.Abs(Math.Sin(crs12)) < EPS))
{
Debug.WriteLine("Warning: Location is at earth's pole. Only N-S courses are meaningful at this location.");
}
lat = Math.Asin(Math.Sin(lat1) * Math.Cos(d12) +
Math.Cos(lat1) * Math.Sin(d12) * Math.Cos(crs12));
if (Math.Abs(Math.Cos(lat)) < EPS)
{
lon = 0.0; //endpoint a pole
}
else
{
dlon = Math.Atan2(Math.Sin(crs12) * Math.Sin(d12) * Math.Cos(lat1),
Math.Cos(d12) - Math.Sin(lat1) * Math.Sin(lat));
lon = ModM.Mod(lon1 - dlon + Math.PI, 2 * Math.PI) - Math.PI;
}
return(new double[] { lat, lon });
}
