Calculating bearing between two CLLocationCoordinate2Ds

Question

Very \"simple\" problem: given two CLLocationCoordinate2Ds, how can I get the bearing (as radians) from the first to the second? I\'ve done a lot of research and studying on

Answer 1

you can use my code.. it's work on my project with microcontroller that use GPS for data.

#define d2r ((22/7.0)/180.0)
#define r2d (180.0/(22/7.0))

double get_heading1(double lat1, double long1, double lat2, double long2)  
{
    double diff_lat, diff_long;
    double degree;

    diff_long =(double) (((long2*1000000)-(long1*1000000))/1000000) * d2r;
    diff_lat = (double) (((lat2*1000000)-(lat1*1000000))/1000000) * d2r;     

    degree = r2d     (atan2(sin(diff_long)*cos(d2r*lat2),cos(d2r*lat1)*sin(d2r*lat2)-sin(d2r*lat1)*cos(d2r*lat2)    *cos(diff_long)));

    if (degree >= 0) {
        return degree;
    } else {
        return 360+degree;
    }                                                                 
}