Hi everyone,
I’m encountering a strange issue with GPS tracking in my app, and I’m hoping for some insights.
I’m developing an app that records users' GPS activities (walking, biking, etc.) with app in the foreground and/or background. Most activities are outdoors, sometimes in areas with poor GPS reception, such as mountains.
To track user location, we’re using:
locationManager = CLLocationManager()
locationManager.distanceFilter = 3
locationManager.activityType = .fitness
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.allowsBackgroundLocationUpdates = true
The Issue
In certain scenarios, the GPS behaves unexpectedly.
For example (see attached image below):
A user followed a normal route (brown line), then reached an intersection and turned right (blue arrow). However, the GPS continued straight for about 200 meters (brown line) before correcting itself and resuming accurate tracking.
Here’s a snippet of the recorded coordinates during this misbehavior:
time,latitude,longitude,elevation,verticalAccuracy,horizontalAccuracy
10:17:17,47.92408,7.10438,950.82375,4.74865,4.80005
10:17:33,47.92410,7.10435,950.14966,4.74865,4.10799
10:17:44,47.92412,7.10431,943.63913,4.74865,4.46287
10:17:53,47.92413,7.10427,939.51380,4.74865,4.60644
10:17:59,47.92415,7.10424,934.82986,4.74865,4.52599
10:18:02,47.92417,7.10420,932.53145,4.74865,4.823035
10:18:05,47.92418,7.10416,927.84917,4.748655,4.59619
10:18:09,47.92420,7.10413,924.89886,4.748655,4.50172
10:18:13,47.92422,7.10409,923.35354,4.74865,4.77356
10:18:18,47.92424,7.104055,920.16327,4.74865,4.78286
10:18:22,47.92426,7.10400,915.23174,4.74865,4.66226
10:18:28,47.92427,7.10397,906.08626,4.74865,4.97331
10:18:31,47.92429,7.10394,903.25157,4.74865,4.81649
10:18:35,47.92431,7.10390,895.27948,4.74865,5.15392
10:18:38,47.92433,7.10386,889.71076,4.74865,5.25283
10:18:42,47.92435,7.10382,881.74041,4.74865,5.49089
10:18:46,47.92437,7.103785,874.34945,4.74865,5.55564
10:18:49,47.92439,7.10374,869.63184,4.74865,5.37537
10:18:53,47.92441,7.10370,861.26690,4.74865,5.39344
10:18:57,47.92443,7.10366,854.67646,4.74865,5.30404
10:19:01,47.92445,7.10362,848.48881,4.74865,5.59742
10:19:06,47.92447,7.10359,836.48915,4.74865,5.65666
10:19:08,47.92449,7.103555,835.72566,4.74865,5.54957
10:19:10,47.92450,7.10352,834.41579,4.74865,5.63540
10:19:13,47.92452,7.10348,830.17080,4.74865,5.65795
10:19:16,47.92454,7.10344,828.17052,4.74865,5.72169
10:19:19,47.92456,7.10340,824.93658,4.74865,5.62606
10:19:24,47.92458,7.10337,818.40503,4.74865,5.23265
10:19:34,47.92460,7.103335,804.42539,4.74865,4.683855
10:19:38,47.92462,7.10329,799.51747,4.74865,4.47590
10:19:48,47.92464,7.10324,784.97044,4.74865,4.59459
10:19:50,47.92466,7.10320,782.04750,4.748655,4.71036
10:19:57,47.92468,7.10317,777.49314,4.74865,4.60504
10:20:05,47.92469,7.10313,771.30168,4.74865,4.35574
10:20:09,47.92472,7.10308,766.64446,4.74865,4.94510
10:20:13,47.92474,7.10304,757.33384,4.74865,5.39175
10:20:15,47.92476,7.10300,753.52157,4.74865,5.442045
10:20:20,47.92477,7.10297,742.66179,4.74865,5.52391
10:20:23,47.92479,7.10293,735.38369,4.74865,5.44657
10:20:25,47.92480,7.10290,732.19367,4.74865,5.519945
10:20:28,47.92482,7.10286,725.15380,4.748655,5.58173
10:20:31,47.92484,7.10282,717.08813,4.74865,5.37805
10:20:34,47.92486,7.102785,710.35208,4.74865,5.27918
10:20:37,47.92488,7.10274,706.16774,4.748655,5.53270
10:20:40,47.92490,7.10270,702.84802,4.74865,5.71088
10:20:41,47.92648,7.10356,940.27115,6.600805,10.78768
10:20:43,47.92651,7.10355,940.24665,6.61807,10.45243
At 10:17:44, the location data was correct.
Shortly after, CLLocationManager started returning inaccurate coordinates. Despite the system reporting good horizontal and vertical accuracy, the altitude readings drop progressively from 940m to 702m, even though the user remained at 940m in reality. (We also recorded barometric elevation, which confirms that he stayed around 900m)
Then, at 10:20:41, the GPS corrected itself.
Questions
Is it possible that GPS could "lock onto" the wrong path, generating valid-looking but incorrect coordinates?
Can we force CLLocationManager to use GPS exclusively (disabling other sensors like Wi-Fi)? I assumed that setting activityType = .fitness would prioritize outdoor tracking, but I’m still being located indoors.
Could adjusting the activityType improve this behavior?
Could having multiple CLLocationManager() instances in our app cause issues? (We use one to save the GPS coordinates, but MapBox also creates a CLLocationManager with lower accuracy for its Telemetry framework, for example)
Thanks in advance for any help or suggestions!
Maps & Location
RSS for tagLearn how to integrate MapKit and Core Location to unlock the power of location-based features in your app.
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Hello.
I’m trying to use Core Location Service on any application in Mac (Safari, Maps, Weather, Chrome with Core Location configuration, or just trigger the API with a standalone app) and it seems that all of them constantly fail to provide the geolocation of my device because of the same error (kCLErrorLocationUnknown).
I'm using MacBook Pro (M3 Max) with Sonoma 14.7.
I’m sure the apps have access in the settings and everything is in order except the Core Location response.
I’ve tested the issue on multiple MacBooks and it reproduced 100% of the times on all of them.
Did anyone encounter a similar issue?
Hi,
Where can I get more information on expected behaviour for the liveUpdates() configuration options, .default, .automotiveNavigation, .fitness, .automotive, .otherNavigation?
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Thanks
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This is a standalone SwiftUI app w/ watchOS 11.
To make things simple, I'm using the new concurrent API, like that:
for try await update in CLLocationUpdate.liveUpdates() { … }
watchOS is supposed to show the auth dialog, but it doesn't show up, even though update.authorizationRequestInProgress is true.
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Hello everyone,
I’m facing an issue with my iOS app where the GPS/location services icon appears in the status bar immediately when the app is launched, even though I’m not intentionally accessing location services at that point.
Issue Summary:
• GPS Icon Activation: When I launch my app, the GPS icon turns on. It turns off when the app is minimized or closed.
• No Intentional Location Usage at Launch: I have ensured that no instances of CLLocationManager are created when the app is launched.
What I’ve Tried So Far:
1. Checked Controllers and Related Classes:
• Reviewed all the code for the controllers that are active at launch.
• Verified that none of these controllers create instances of CLLocationManager or call location-related methods.
2. Commented Out startUpdatingLocation:
• Commented out all calls to startUpdatingLocation throughout the entire project.
3. Ensured No CLLocationManager Instances at Launch:
• Searched for any code that might instantiate CLLocationManager during app launch.
• Confirmed that no such instances are being created.
4. Commented Out Google Maps SDK Configuration:
• In AppDelegate, commented out the Google Maps SDK configuration, so it’s not initialized with the API key.
• No map views (GMSMapView, MKMapView) are initialized or used when the app is launched.
5. Tested Location Permissions:
• When I change the location permission for the app to “Never” in the Settings app, the GPS icon does not appear upon app launch.
• This suggests that the app is accessing location services when it has permission, even though I haven’t explicitly requested it at launch.
Objective:
• Control GPS Activation: I want to ensure that the GPS does not turn on when the app is launched. I intend to activate location services only when needed later in the app.
Request for Assistance:
I’m seeking guidance on the following:
1. Debugging Techniques:
• How can I trace the code that’s causing the GPS to turn on at app launch?
• Are there tools or methods to identify hidden or indirect calls to location services?
2. Forcing Location Services Off at Launch:
• Is there a way to programmatically prevent location services from activating during app launch?
• Can I defer any implicit location service initialization until I explicitly enable it?
3. Potential Hidden Triggers:
• Are there known scenarios where location services could be activated without direct use of CLLocationManager?
• Could frameworks like Google Maps SDK trigger location services even if not fully initialized?
4. Additional Suggestions:
• Any other insights or suggestions to prevent the GPS icon from appearing on app launch.
Additional Information:
• Third-Party Frameworks:
• I have not removed third-party frameworks yet, as I wanted to check other possibilities first.
• Open to the idea that a third-party framework might be causing this, but need guidance on how to confirm.
• Code Availability:
• I’m happy to provide specific code snippets if that would help diagnose the issue.
Environment:
• Xcode Version: Xcode 15.4, Xcode 16.0
• iOS Deployment Target: iOS 15.0
• Devices Tested: iPhone SE 2nd and 3rd gen, iPhone 15, iPhone 15 pro, iPhone 11
• Programming Language: Swift
What I’m Looking For:
• Assistance in tracing the cause of the GPS activation on app launch.
• Suggestions on how to prevent location services from starting until explicitly needed.
• Insights into any hidden triggers or indirect usages that might cause this behavior.
Thank you for your time and assistance. Any help to resolve this issue would be greatly appreciated.
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Hello,
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CLLocationManager:
let manager: CLLocationManager = {
let manager = CLLocationManager()
manager.distanceFilter = kCLDistanceFilterNone
manager.desiredAccuracy = kCLLocationAccuracyThreeKilometers
manager.pausesLocationUpdatesAutomatically = false
manager.activityType = .other
manager.showsBackgroundLocationIndicator = true
manager.allowsBackgroundLocationUpdates = true
return manager
}()
Thank you!
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I'm encountering an issue when using MKLocalSearch to search for cities. Here's my setup:
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I've set the resultTypes to .address to focus on address results.
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When I receive the search response, it includes the locations as expected. However, these locations don't have an identity or alternative identities.
Questions:
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Without an identity, how can I uniquely identify and store these city results in my database?
Would it be appropriate to store the city name, country, and coordinates instead?
Thanks in advance!
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I created a navigation app that uses a map overlay for finite spaces such as a zoo. I get these overlays created by a designer in .PNG - the designer creates the overlays and then puts a square or rectangle box around the overlay because it needs to be placed in 9 pieces making it easier to render when user zooms in/out...
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Alternatively, if you pass the coordinate in via Apple Maps URL (https://maps.apple.com/?daddr=49.110,-112.110) it will route but the route is no longer to those specific coordinates, Apple Maps alters them to some nearest known entity (in this case, the RM of Warner County). If you compare the suggested route end destination with the search results for specifically entering the coordinates, you will see they are different locations and mapping routes are not actually taking you to the coordinates anymore.
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If I visualise a generic map I have the scale in km.
When I change the MKMapRect using visibleMapRect, the scale doesn't change.
If I use setVisibleMapRect(_ mapRect: MKMapRect, animated animate: Bool), the scale change but not to the correct one. For example, it shows a scale saying one inch corresponds to 250 m while it is 150 m.
The same issue of I use MKCoordinateRegion.
Instead, if I zoom in or zoom out pinching on the map, the scale updates correctly.
Am I doing something wrong? How can I fix this?
Sample code:
import UIKit
import MapKit
let CORNER_RADIUS: CGFloat = 8.0
let METERS_PER_MILE: Double = 1609.344
class PIAnnotation: NSObject, MKAnnotation {
var coordinate: CLLocationCoordinate2D
private(set) var title: String?
private(set) var subtitle: String?
init(location: CLLocationCoordinate2D,
title: String? = nil, subtitle: String? = nil) {
coordinate = location
self.title = title
self.subtitle = subtitle
}
}
class PISimpleMapView: MKMapView {
private let HALF_MAP_SIDE_MULTIPLIER: Double = 1.4
private let pinIdentifier = "pinIdentifier"
private var scaleView: MKScaleView?
typealias PinAnnotationView = MKMarkerAnnotationView // MKPinAnnotationView
required init?(coder: NSCoder) {
super.init(coder: coder)
inizialize()
}
override init(frame: CGRect) {
super.init(frame: frame)
inizialize()
}
func inizialize() {
layer.cornerRadius = CORNER_RADIUS
register(PinAnnotationView.self,
forAnnotationViewWithReuseIdentifier: pinIdentifier)
addScale()
}
private func addScale() {
let scale = MKScaleView(mapView: self)
scale.translatesAutoresizingMaskIntoConstraints = false
scale.scaleVisibility = .visible // always visible
addSubview(scale)
let guide = safeAreaLayoutGuide
NSLayoutConstraint.activate([
scale.leftAnchor.constraint(equalTo: guide.leftAnchor, constant: 16.0),
scale.rightAnchor.constraint(equalTo: guide.centerXAnchor),
scale.topAnchor.constraint(equalTo: guide.topAnchor),
scale.heightAnchor.constraint(equalToConstant: 20.0)
])
scaleView?.removeFromSuperview()
scaleView = scale
}
func displayPinOnMap(location: CLLocation) {
let annotation = PIAnnotation(location: location.coordinate,
title: "Sample", subtitle: nil)
addAnnotation(annotation)
// Position the map so that all overlays and annotations are visible on screen.
visibleMapRect = visibleArea(from: annotation)
// setVisibleMapRect(visibleArea(from: annotation), animated: true)
// region = MKCoordinateRegion(visibleArea(from: annotation))
}
private func visibleArea(from annotation: PIAnnotation) -> MKMapRect {
let annotationPoint = MKMapPoint(annotation.coordinate)
return MKMapRect(x: annotationPoint.x - HALF_MAP_SIDE_MULTIPLIER * METERS_PER_MILE,
y: annotationPoint.y - HALF_MAP_SIDE_MULTIPLIER * METERS_PER_MILE,
width: HALF_MAP_SIDE_MULTIPLIER * 2.0 * METERS_PER_MILE,
height: HALF_MAP_SIDE_MULTIPLIER * 2.0 * METERS_PER_MILE)
}
}
It’s taking longer to get direction after you put the addres.