Calculate bearing between two locations (lat, long)

Question

I\'m trying to develop my own augmented reality engine.

Searching on internet, I\'ve found this useful tutorial. Reading it I see that the important thing is bearing

Answer 1

a in the diagram is the longitude difference, b is the latitude difference therefore in the method you have written you've got them the wrong way round.

a = destination.latitude - user.latitude; // should be b
b = destination.longitude - user.longitude; // should be a

Try switching them and see what happens.

See Palund's response for answers to the rest of your questions.