How do I calculate the Azimuth (angle to north) between two WGS84 coordinates

Question

I have got two WGS84 coordinates, latitude and longitude in degrees. These points are rather close together, e.g. only one metre apart.

Is there an easy way to calcu

Answer 1

Here is the C# solution. Tested for 0, 45, 90, 135, 180, 225, 270 and 315 angles.

Edit I replaced my previous ugly solution, by the C# translation of Wouter's solution:

public double GetAzimuth(LatLng destination)
{
    var longitudinalDifference = destination.Lng - this.Lng;
    var latitudinalDifference = destination.Lat - this.Lat;
    var azimuth = (Math.PI * .5d) - Math.Atan(latitudinalDifference / longitudinalDifference);
    if (longitudinalDifference > 0) return azimuth;
    else if (longitudinalDifference < 0) return azimuth + Math.PI;
    else if (latitudinalDifference < 0) return Math.PI;
    return 0d;
}

public double GetDegreesAzimuth(LatLng destination)
{
    return RadiansToDegreesConversionFactor * GetAzimuth(destination);
}