GoogleNavigation Framework Reference

GMSGeometryHeading

extern CLLocationDirection GMSGeometryHeading(CLLocationCoordinate2D from,
                                              CLLocationCoordinate2D to)

Returns the initial heading (degrees clockwise of North) at from of the shortest path to to.

The returned value is in the range [0, 360).

Returns 0 if the two coordinates are the same.

Both coordinates must be valid.

To get the final heading at to one may use (GMSGeometryHeading(to, from) + 180) modulo 360.