polyline on the google map in realtime not working - ios

Question

I'm trying to draw polyline in realtime to show users the route they have taken so far. I use google map api, and so far, it shows users' current location with no problem. But polyline doesn't work though (It doesn't draw polyline at all). I call startMonitoringSignificantLocationChanges after I check for authorization and draw the polyline inside didupdatelocations. Here's an relevant part of my code :
extension MapViewController: CLLocationManagerDelegate {
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
if status == .AuthorizedAlways {
locationManager.startUpdatingLocation()
mapView.myLocationEnabled = true
mapView.settings.myLocationButton = true
locationManager.startMonitoringSignificantLocationChanges()
}
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let location = manager.location {
mapView.camera = GMSCameraPosition(target: location.coordinate, zoom: 15, bearing: 0, viewingAngle: 0)
path.addCoordinate(CLLocationCoordinate2D(latitude: location.coordinate.latitude,
longitude: location.coordinate.longitude))
let polyline = GMSPolyline(path: path)
polyline.strokeColor = UIColor.redColor()
polyline.strokeWidth = 3
polyline.map = mapView
locationManager.stopUpdatingLocation()
}
}
UPDATE-1
After commenting out stopUpdatingLocation line, it does draw the line. But the line is mangled mess.
UPDATE-2
I figured out why the line is a mess instead of one straight line. It's because iphone is changing current location consistently(even though it is stationary), therefore, drawing multiple lines in a small area. How do I stop iphone from doing that?
UPDATE-3
I just found out that "Jumpy" current location does not only happen in my app. It also happens in GoogleMap app. So this is probably Iphone/ios GPS issue.

Answer 1

You just need to ignore invalid location updates or the updates with low accuracy.
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
CLLocation *location = [locations lastObject];
NSTimeInterval age = -[location.timestamp timeIntervalSinceNow];
if (age > 120) return; // ignore old (cached) updates
if (location.horizontalAccuracy < 0) return; // ignore invalid updates
if (location.horizontalAccuracy <=10) //you can change 10 to 20 if you want more frequent updates
{
// this is a valid update
}
}
Hope this helps.