Question

In Xcode 4.5 apple introduced apple new maps. My application heavliy requires map services. And I have noticed in my application it shows the wrong current location until you delete the app and reopen it shows the right current location (Sometimes it doesn’t). Just to mention I was connected to 4G when it show the wrong current location. Is there a way to fix this bug because my application heavily needs the right location. Thanks in advance. If you could provide code it would help a lot…Edit: Same Issue in Apple Map App

My Code:

- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation {
    {

    }

    if (!oldLocation)
        totalDistance = 0.0;
    else
        totalDistance += [newLocation distanceFromLocation:oldLocation];

}

Answer 1

The old approach from apple docs seems still working in iOS6 (didn’t notice this in my active app (it tracks user’s route via gps))

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {

    NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow];
    if (locationAge > 5.0) return;
    if (newLocation.horizontalAccuracy < 0) return; 

    // proceed with coords here
}

UPDATE from the discussion:
Calculating total and current distance could be done like this (excluding some minor stuff):

// somewhere at the top
CLLocation* lastUsedLocation = nil; // last location used in calculation
CLLocation* pointA = nil;  // start of the track
double totalDistance = 0;  // total distance of track
double currentDistance = 0; // distance between startTrack point and current location
...

// when you start updating location:
- (void) startTracking {
    lastUsedLocation = nil;
    pointA = nil;
    totalDistance = 0;
    currentDistance = 0;
    [locationManager startUpdatingLocation];
}
...


// location update callback
 - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { 
    NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow]; 
    if (locationAge > 5.0) return;  // filter cached
    if (newLocation.horizontalAccuracy < 0) return; // filter invalid

    if(!pointA) pointA = [newLocation retain]; 

    if(lastUsedLocation) 
    { 
        totalDistance += [newLocation distanceFromLocation:lastUsedLocation]; 
    } 
    currentDistance = [pointA distanceFromLocation:newLocation]; 
    [lastUsedLocation release]; 
    lastUsedLocation = [newLocation retain]; 
}

If you need the option to turn off background location on purpose you disable it manually like:

- (void)applicationDidEnterBackground:(UIApplication *)application {
    if(backgroundLocationDisabled)
    {
        [locationManager stopUpdatingLocation];
        // additional stuff
    }
}