CLLocationManager weird issues

Question

I have a MKMapView whereby I drop an annotation everytime the view loads, or when showLocation custom class method is called.

I need the accuracy to be the best

-(void)viewDidLoad {
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.distanceFilter = kCLDistanceFilterNone; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
    [locationManager startUpdatingLocation];
}
-(IBAction) showLocation:(id) sender{
    [locationManager startUpdatingLocation];
}
- (void) locationManager:(CLLocationManager *) manager
     didUpdateToLocation:(CLLocation *) newLocation
            fromLocation:(CLLocation *) oldLocation {
// start geocoding with newLocation coordinate which will automatically set annotation.
SVGeocoder *geocodeRequest = [[SVGeocoder alloc] 
                                      initWithCoordinate:CLLocationCoordinate2DMake(newLocation.coordinate.latitude, newLocation.coordinate.longitude)];
        [geocodeRequest setDelegate:self];
        [geocodeRequest startAsynchronous];
        [geocodeRequest release];
            [locationManager stopUpdatingLocation];
}

My question is when will the didUpdateToLocation method be called? Only after a new location is found when I perform [locationManager startUpdatingLocation]?

I am facing some weird issue when the user is travelling and on stationary. Say the user is travelling from point A->B->C->D with 1 min intervals between points. When I call my method at point C, sometime it returns the coordinates of point A, sometimes point B and sometimes C. It's just random.

It's even more weird when I am on stationary. I get different coordinates when I calls showLocation method even though I am hooked up on my house WiFi.

I was thinking of implementing the didUpdateToLocation to get the best result it can within 5secs. If within the 5secs, it finds a particular location of an accuracy I had defined, then use the coordinate. If not, use the best it has found within the 5sec time frame. But as I am new I am not sure how to code something like that. I read up NSTimer and it seems like it might work.

Any advices guys?

Thanks a lot in advance!

score 1 · Accepted Answer · answered Sep 05 '11 at 11:58

One of the reasons you are receiving the location from point A is that CoreLocation is returning the last valid location it had first until it can obtain a more accurate location. When you call [locationManager startUpdatingLocation]; it will return the -didUpdateToLocation over and over until you are statisfied and finally call -stopUpdatingLocation.

I think you just need to allow a bit of time for it to get a better location fix before you stop updating your location. I would consider moving the stop updating location from your -didUpdateToLocation to a different method.

score 0 · Answer 2 · answered Sep 05 '11 at 11:43

0

Remove [locationManager stopUpdatingLocation]; from your code and try .

answered Sep 05 '11 at 11:43

Narayanan Ramamoorthy

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CLLocationManager weird issues

2 Answers2