I have a problem which i don't understand how to achieve. Maybe someone could sheed some light on it.
Have a look at this picture:
What I try to achieve is to determine the point D on the geodesic line AB with the minimal distance to C, given the points A, B, C. All points are on the surface of an ellipsoid with given latitude and longitude.
I know that in the plane I can use Vector Projection to determine D easily. But I don't know how to achieve this on an ellipsoid. To calculate the distances between the given points isn't a problem.