CLLoacationManager class returning cached data - iphone

Question

How to remove cached data which is sent by CLLocationManager and how to increase its accuracy.Every time i launch the app it gives me cached data and updates it after some time.I have seen several threads but i am not able to get a concrete sol .can anybody provide me the code?
I am using the following method to get position data....
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
I have set the delegate and accuracy here.....
- (void)viewDidLoad {
[super viewDidLoad];
bestEffortAtLocation = nil;
latLocationArray = [[NSMutableArray alloc]init];
longLocationArray = [[NSMutableArray alloc]init];
locationManager =[[CLLocationManager alloc]init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager startUpdatingLocation];
}
Also can i use CLLocationManager to compute the distance travelled by person?

Answer 1

There doesn't seem to be a way to dump the cached data. The docs recommend using the timestamp property of the CLLocation object to determine how recent the data is, which is what I do.
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
//wait until we get a recent location, no more than 2 minutes old
if([newLocation.timestamp timeIntervalSinceNow] <= (60 * 2)){
DLog(#"New location:\n\tLat: %f\n\tLon: %f", newLocation.coordinate.latitude, newLocation.coordinate.longitude)
//turn off location updates
[self.locManager stopUpdatingLocation];
DLog(#"Stopping Location Updates");
//Do stuff
}
}
In my testing I haven't had to wait more than a second or two before I get new data.
On your second point, you could have a variable that you add to whenever you get a location update. The distance between updates can be pretty easy to get using CLLocation's distanceFromLocation: method.

Answer 2

Instead of set the distanceFilter to kCLDistanceFilterNone
i.e. locationManager.distanceFilter = kCLDistanceFilterNone;
You may give some value to distanceFilter and check
For e.g. locationManager.distanceFilter =0.5f;
And to calculate distance travel you have to implement the didUpdateToLocation: fromLocation:
where you have to find the new latitude and longitude
Finally
CLLocationObject = newLocation;
CLLocationDistance yourdistance = [newLocation getDistanceFrom:CLLocationObject];
NSString *distance = [[NSString alloc]
initWithFormat:#"%gm", yourdistance ];
NSLog(#"you have travel=%#",distance);