CLLocationManager tracks wrong location (Track Me)
I am using parameter Track me
in my code. CLLocationManager
does not work as expected. When I launch the app, stay in the same position, CLLocationManager
change by about 20-30 meters in 1 minute. then I remain constant.
And if I change my position to keep track of the same thing that happens at the beginning of 1 min. CLLocationManager
moves for 20-30 minutes and then moves at my speed.
Why is this happening..
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
self.locationManager.distanceFilter = 0.0001;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
}
-(void)start {
[self.locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager*)manager
didUpdateToLocation:(CLLocation*)newLocation
fromLocation:(CLLocation*)oldLocation {
[self processLocationChange:newLocation fromLocation:oldLocation];
}
-(void)processLocationChange:(CLLocation*)newLocation fromLocation:oldLocation {
if (newLocation != oldLocation) {
NSLog(@"Moved from %@ to %@", oldLocation, newLocation);
CLLocation* lastKnownLocation = NULL;
if ([self.locationPoints count] > 0) {
lastKnownLocation = [self.locationPoints objectAtIndex:[self.locationPoints count] - 1];
}
else {
lastKnownLocation = newLocation;
self.bottomLeft = newLocation.coordinate;
self.topRight = newLocation.coordinate;
}
// Check for new boundaries
CLLocationCoordinate2D coords = newLocation.coordinate;
if (coords.latitude < bottomLeft.latitude || coords.longitude < bottomLeft.longitude) {
self.bottomLeft = coords;
NSLog(@"Changed bottom left corner");
}
if (coords.latitude > topRight.latitude || coords.longitude > topRight.longitude) {
self.topRight = coords;
NSLog(@"Changed top right corner");
}
double speed = fabs(newLocation.speed);
double deltaDist = fabs([newLocation distanceFromLocation:lastKnownLocation]);
double newAvgSpeed = (self.totalDistance + deltaDist) / ((double)[self getElapsedTimeInMilliseconds] / 1000.0);
double accuracy = newLocation.horizontalAccuracy;
double alt = newLocation.altitude;
NSLog(@"Change in position: %f", deltaDist);
NSLog(@"Accuracy: %f", accuracy);
NSLog(@"Speed: %f", speed);
NSLog(@"Avg speed: %f", newAvgSpeed);
self.totalDistance += deltaDist;
self.currentSpeed = speed;
self.avgSpeed = newAvgSpeed;
self.altitude = alt;
NSLog(@"Delta distance = %f", deltaDist);
NSLog(@"New distance = %f", self.totalDistance);
// Add new location to path
[self.locationPoints addObject:newLocation];
// Update stats display
[self.first.start1 updateRunDisplay];
// Update map view
[self updateMap:lastKnownLocation newLocation:newLocation];
}
}
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I faced the same issue in my current Pedometer app. I stretched, hit my head for a couple of days. Then I found out that I was CLLocationManager
not able to track distance up to 5 meters and location. I saved self.locationManager.distanceFilter =2.0;
and it gave me location updates, even the device was stationary. So I just changed the distance format to 5.0 meters and it started working fine. Try to take 5 meters, it should work, I tested and all my wrong notification questions disappeared:
self.locationManager.distanceFilter =5.0;
You take self.locationManager.distancefilter=0.0001
, which, I believe, is not capable of CLLocationManager
tracking such minor movement. Also you need to filter out old locations, i.e. cached location updates, as mentioned in Apple's Location Awareness Guide . I used this condition in my code to filter all events that are older than 5 seconds.
- (void)locationManager:(CLLocationManager *)manager
didUpdateLocations:(NSArray *)locations
{
CLLocation *currentLocation=[locations lastObject];
NSDate* eventDate = currentLocation.timestamp;
NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
if(abs(howRecent)<5.0 && self.currentLocation.horizontalAccuracy<=10 && self.currentLocation.horizontalAccuracy>0)
{
//you have got fresh location event here.
}
}
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I find the distance filter is effective with this
self.locationManager.distanceFilter = kCLDistanceFilterNone;
and you can start updating the location method, but also try this method, both methods are needed to get the exact location
[locationManager startMonitoringSignificantLocationChanges];
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