計算iPhone 2經度和緯度之間的航向

Question

可能重複：
how to calculate the current speed and average speed of user travelling from current location to particular loaction in map in iphone

我有一個情況我不應該使用CLLocationManger class.I我有兩個緯度和經度給出值（來源和目的地）。我想從iPhone中的這兩點找出標題。我該如何做？

我提到的公式在此link。但我不能夠得到heading.Please任何機構幫助我在計算標題

謝謝大家提前。

Answer 1

你在這裏。這些是您可以用來計算2個位置之間距離的2個功能。

-(float)getDistanceInKm:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{ 
    float lat1,lon1,lat2,lon2; 

    lat1 = newLocation.coordinate.latitude * M_PI/180; 
    lon1 = newLocation.coordinate.longitude * M_PI/180; 

    lat2 = oldLocation.coordinate.latitude * M_PI/180; 
    lon2 = oldLocation.coordinate.longitude * M_PI/180; 

    float R = 6371; // km 
    float dLat = lat2-lat1; 
    float dLon = lon2-lon1; 

    float a = sin(dLat/2) * sin(dLat/2) + cos(lat1) * cos(lat2) * sin(dLon/2) * sin(dLon/2); 
    float c = 2 * atan2(sqrt(a), sqrt(1-a)); 
    float d = R * c; 

    NSLog(@"Kms-->%f",d); 

    return d; 
} 

-(float)getDistanceInMiles:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{ 
    float lat1,lon1,lat2,lon2; 

    lat1 = newLocation.coordinate.latitude * M_PI/180; 
    lon1 = newLocation.coordinate.longitude * M_PI/180; 

    lat2 = oldLocation.coordinate.latitude * M_PI/180; 
    lon2 = oldLocation.coordinate.longitude * M_PI/180; 

    float R = 3963; // km 
    float dLat = lat2-lat1; 
    float dLon = lon2-lon1; 

    float a = sin(dLat/2) * sin(dLat/2) + cos(lat1) * cos(lat2) * sin(dLon/2) * sin(dLon/2); 
    float c = 2 * atan2(sqrt(a), sqrt(1-a)); 
    float d = R * c; 

    NSLog(@"Miles-->%f",d); 

    return d; 
} 

希望它有幫助。