I'm building an app that uses CoreLocation to get user's coordinates. After I start updating location, I'll get the coordinates in didUpdateLocations. Probably because of gps calibration, in didUpdateLocations I get 2 or 3 different coordinates, until it stops. How can I call a function after updating locations has stopped that uses the last founded coordinates?
Allow didUpdateLocations: to be called repeatedly, as you rightly say, until either you hit some kind of timeout or your get sufficient horizontal accuracy. Then, right from didUpdateLocations:, tell the location manager to stop, and call the function.
Related
For an app I am making I track the users location on a map. When outdoors, I am able to get the coordinates of the users position almost instantly and the app works great. Indoors, as expected, does not have GPS signal so I cannot get the location. That said, iOS uses Wifi and various other techniques to show my approximate location on a MapView still. However, I am unable to get the approximate coordinate while indoors even though iOS knows it (ie. didUpdateLocations is never called while indoors but is the second I walk out the door). I'm wondering if there is a way to get an approximate coordinate while indoors (I don't need exact).
I am using a CLLocationManager to get the location data in my ios app, I am using locationManager.distanceFilter method to update how often I want to update my location.
Does this method record the location every time the device moves at least that much of distance? and what happens if it is set to 0? will it update the location even if the location is not changing?
Any help would be appreciated.
With the distance filter set to 0 you should get new location about every 1 second. All of them will be slightly different even if you are not moving because GPS/GLONASS accuracy is not perfect. If you set it to some bigger value next location will be reported only when the distance between locations will be greater than specified value.
what's the efficient way to keep track user's location? I mean I do not care if the location has been change slightly, because it will waste the resources.
i used in my code: LocationManager.stopUpdatingLocation()
to stop every small changes in location...
is there a way to keep track the location only if it oldLocation and newLocation has big different?
Yes there are two ways you can achieve that. First way is to use
func startMonitoringSignificantLocationChanges()
startMonitoringSignificantLocationChanges starts the generation of updates based on significant location changes. Apps can expect a notification as soon as the device moves 500 meters when you are using startMonitoringSignificantLocationChanges. And if you want to use startUpdatingLocation then set distanceFilter to distance of your choice and it will report location only if location change is more than distance specified in filter. distanceFilter represents the minimum distance (measured in meters) a device must move horizontally before an update event is generated.
I am using CLLocationManager didUpdateLocations to get current location of device.
Its provide me the current location but after in few seconds I am getting different latitude and longitude for the same place with no movement in device.
I want to implement 5 metre distance check in my app, but due to frequently change in location provided by delegate method I always getting the more than 5 meter difference between old and new location.
Can anybody suggest what is the best way to find out accurate distance.
i use CLLocation for a app that record people's trace in map view when they are running or walking ,but i found when my device is still (not moved) ,the
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations is also get called frequently ?
currently ,my locationmanager's desiredAccuracy is 10 meters and distanceFilter is 10.
how to deal with this situation? I have tried use big distancefilter value(like 150) ,but I found if i do this, then i can't record exactly when people is running or walking
GPS is not exact. You can move around a few feet and get the same location. Or you can sit still and get told you have moved a few feet.
You might be able to combine measurements from the accelerometer to determine if you have really moved but this would only work if the device was sitting on a table not moving.
Have you called stopUpdatingLocation after the initial startUpdatingLocation? It will keep updating location if you do not call it.
How does system know whether or not you have actually moved? It MUST fetch your location to find out. The more accurate your desired accuracy is, the more vigorously and frequently it would look. By vigorous I mean if it's suppose to use cell-tower information then it would look into more cell-towers to better triangulate. Or simply put it, the interval between its fetches would be smaller. Concluding: OS would fetch data even if you don't move.
Additionally to triangulate your position the OS (depending on your desiredAccuracy and previous movements) would use a mix of GPS, wifi, Cell-tower. And because someone may all of sudden turn off/on their wifi, or satellite that you were using to get your location has moved a bit or the satellites have changed, or a cell-tower signal may become more or less accurate due to its bandwidth limitations then your calculated location may change which triggers a callback if it's more than your distanceFilter. ( I don't believe you get callbacks for less than your distanceFilter, but I may be wrong) This likely means your distanceFilter is set to very small number which depending on your business requirements may or may not be a good choice. Concluding: your location is never ever 100% accurate
The result of periodical fetching, possibility of error and small distanceFilters lead to possible incorrect locationChanges.