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We experience some weird issues on the locations from CCLocationManager starting from iOS9. iOS 7-8 has no issues. The weird locations cause errors in the app. The app is used while driving a car and we have about 50 test users in TestFlight and some of them are reporting these issues.
The app reacts on location updates, each location update, each 25m and each 50m there is something to do. For test I've stored all these locations in an array. Our test users have a button which will send the history in GPX format to me by mail.
For example the following 12 locations where send to me:
<?xml version="1.0" encoding="UTF-8"?>
<gpx xmlns="http://www.topografix.com/GPX/1/1" version="1.1" creator="flitsmeister-ios-app-test" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
<wpt lat="51.28165091" lon="5.77329012">
<datetimegps>2015-09-29T04:36:55.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:55.460</datetimeprocessed>
<course>61.5</course>
<speed>13.3</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.1</altitude>
<sequencenr>0</sequencenr>
</wpt>
<wpt lat="51.28138654" lon="5.77244497">
<datetimegps>2015-09-29T04:36:55.506</datetimegps>
<datetimeprocessed>2015-09-29T04:36:55.523</datetimeprocessed>
<course>69.3</course>
<speed>13.5</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.7</altitude>
<sequencenr>1</sequencenr>
</wpt>
<wpt lat="51.28171319" lon="5.77345935">
<datetimegps>2015-09-29T04:36:56.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:56.441</datetimeprocessed>
<course>61.2</course>
<speed>13.2</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.0</altitude>
<sequencenr>2</sequencenr>
</wpt>
<wpt lat="51.28138654" lon="5.77244497">
<datetimegps>2015-09-29T04:36:56.562</datetimegps>
<datetimeprocessed>2015-09-29T04:36:56.571</datetimeprocessed>
<course>69.3</course>
<speed>13.5</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.7</altitude>
<sequencenr>3</sequencenr>
</wpt>
<wpt lat="51.28177064" lon="5.77362548">
<datetimegps>2015-09-29T04:36:57.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:57.440</datetimeprocessed>
<course>60.1</course>
<speed>13.4</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>32.9</altitude>
<sequencenr>4</sequencenr>
</wpt>
<wpt lat="51.28138654" lon="5.77244497">
<datetimegps>2015-09-29T04:36:57.541</datetimegps>
<datetimeprocessed>2015-09-29T04:36:57.558</datetimeprocessed>
<course>69.3</course>
<speed>13.5</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.7</altitude>
<sequencenr>5</sequencenr>
</wpt>
<wpt lat="51.28182383" lon="5.77380183">
<datetimegps>2015-09-29T04:36:58.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:58.438</datetimeprocessed>
<course>61.2</course>
<speed>13.7</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.3</altitude>
<sequencenr>6</sequencenr>
</wpt>
<wpt lat="51.28138654" lon="5.77244497">
<datetimegps>2015-09-29T04:36:58.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:58.491</datetimeprocessed>
<course>69.3</course>
<speed>13.5</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.7</altitude>
<sequencenr>7</sequencenr>
</wpt>
<wpt lat="51.28188803" lon="5.77398322">
<datetimegps>2015-09-29T04:36:59.371</datetimegps>
<datetimeprocessed>2015-09-29T04:36:59.431</datetimeprocessed>
<course>61.5</course>
<speed>14.4</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.4</altitude>
<sequencenr>8</sequencenr>
</wpt>
<wpt lat="51.28202386" lon="5.77435235">
<datetimegps>2015-09-29T04:37:01.371</datetimegps>
<datetimeprocessed>2015-09-29T04:37:01.432</datetimeprocessed>
<course>61.2</course>
<speed>14.9</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.5</altitude>
<sequencenr>9</sequencenr>
</wpt>
<wpt lat="51.28188803" lon="5.77398322">
<datetimegps>2015-09-29T04:37:01.444</datetimegps>
<datetimeprocessed>2015-09-29T04:37:01.454</datetimeprocessed>
<course>61.5</course>
<speed>14.4</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.4</altitude>
<sequencenr>10</sequencenr>
</wpt>
<wpt lat="51.28208027" lon="5.77454128">
<datetimegps>2015-09-29T04:37:02.371</datetimegps>
<datetimeprocessed>2015-09-29T04:37:02.430</datetimeprocessed>
<course>61.9</course>
<speed>15.1</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.3</altitude>
<sequencenr>11</sequencenr>
</wpt>
<wpt lat="51.28188803" lon="5.77398322">
<datetimegps>2015-09-29T04:37:02.513</datetimegps>
<datetimeprocessed>2015-09-29T04:37:02.521</datetimeprocessed>
<course>61.5</course>
<speed>14.4</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.4</altitude>
<sequencenr>12</sequencenr>
</wpt>
<wpt lat="51.28217918" lon="5.77472677">
<datetimegps>2015-09-29T04:37:03.371</datetimegps>
<datetimeprocessed>2015-09-29T04:37:03.434</datetimeprocessed>
<course>61.5</course>
<speed>15.2</speed>
<accuracyhorizontal>5.0</accuracyhorizontal>
<accuracyvertical>3.0</accuracyvertical>
<altitude>33.5</altitude>
<sequencenr>13</sequencenr>
</wpt>
</gpx>
If I print these location on a map (geoplaner.com is my friend), I will see this:
Remark: Points B D F H are on the same location, but for the illustration of the problem I have put those on 1 row next to each other.
As you can see if you follow the sequence A,B,C you will see that point B is not on the right location.
Starting from iOS9 build almost every test user has experienced this situation once or two times in a week.
Following some code we use:
CLLocationManager (on the mean thread):
_manager = [[CLLocationManager alloc] init];
_manager.delegate = self;
_manager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
_manager.activityType = CLActivityTypeAutomotiveNavigation;
_manager.pausesLocationUpdatesAutomatically = TRUE;
if([_manager respondsToSelector:@selector(allowsBackgroundLocationUpdates)])
_manager.allowsBackgroundLocationUpdates = TRUE;
[_manager requestAlwaysAuthorization];
In another method I call the start (also when app starts and stop it when it terminates). (main thread)
[_manager startUpdatingLocation];
Code for working with Locations (I've removed some code to keep the example clean):
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
CLLocation *lastLocation = [locations lastObject];
// test that the horizontal accuracy does not indicate an invalid measurement
if (lastLocation.horizontalAccuracy < 0)
return;
// test the age of the location measurement to determine if the measurement is cached
// in most cases you will not want to rely on cached measurements
NSTimeInterval locationAge = -[lastLocation.timestamp timeIntervalSinceNow];
if (locationAge > 5.0)
return;
NSDate *dateLocationArrived = [NSDate date];
CLLocation *beforeLocationRealtime = [self.LastLocationRealtime copy];
CLLocation *newLocation = [lastLocation copy];
//Realtime location.
[self setSpeedForLocation:[newLocation copy] withOldRealtimeLocation:[beforeLocationRealtime copy]];
[_delegateKaart updatedRealtimeLocation:newLocation fromPreviousLocation:[self.PreviousCurrentLocation copy]];
self.BeforeLastLocationRealtime = [self.LastLocationRealtime copy];
self.LastLocationRealtime = [newLocation copy];
if([self.CurrentLocation distanceFromLocation:newLocation] < 50) //Less then 50m?
{
if([_locationEach25m distanceFromLocation:newLocation] > 25)
{
//Nieuwe last 25m.
_locationEach25m = [newLocation copy];
//Each 25m do
[_delegateDashboard updatedLocation:[newLocation copy]];
[_delegateSignalering locationUpdated:[newLocation copy]];
[self holdLast200LocationsAndAddLocation:[lastLocation copy] withLocationArray:locations AndArriveDate:dateLocationArrived AndVerwerkt:TRUE];
}
else
[self holdLast200LocationsAndAddLocation:[lastLocation copy] withLocationArray:locations AndArriveDate:dateLocationArrived AndVerwerkt:FALSE];
return;//Stop
}
//Each 50m
[self holdLast200LocationsAndAddLocation:[lastLocation copy] withLocationArray:locations AndArriveDate:dateLocationArrived AndVerwerkt:TRUE];
_locationEach25m = [newLocation copy]; //Also new last 25m .
self.PreviousCurrentLocation = [self.CurrentLocation copy];//50m back.
self.CurrentLocation = [newLocation copy];
[_delegateDashboard updatedLocation:[newLocation copy]];
[_delegateSignalering locationUpdated:[newLocation copy]];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[_delegateCountryDetector locationUpdated:[newLocation copy]];
[self setHuidigeWegForLocation:[newLocation copy]];
});
[[SignaleringController sharedInstance] runSignaleringCheckForLocation:[newLocation copy]];
}
It feels like an iOS9 bug in the locationmanager which is giving me incorrect results on the whereabouts of the user. If I search Stackoverflow.com it seems Im the only one.
<wpt lat="52.32835728" lon="5.05861943">
<datetimegps>2015-10-01T06:27:29.905</datetimegps>
<datetimearrivedincode>2015-10-01T06:27:30.196</datetimearrivedincode>
<datetimeprocessed>2015-10-01T06:27:30.205</datetimeprocessed>
<c>138.4</c>
<s>26.5</s>
<accuracyhorizontal>10.0</accuracyhorizontal>
<accuracyvertical>6.0</accuracyvertical>
<al>5.9</al>
<nr>95</nr>
</wpt>
<wpt lat="52.32813366" lon="5.05927501">
<datetimegps>2015-10-01T06:27:31.905</datetimegps>
<datetimearrivedincode>2015-10-01T06:27:32.275</datetimearrivedincode>
<datetimeprocessed>2015-10-01T06:27:32.301</datetimeprocessed>
<c>119.5</c>
<s>26.0</s>
<accuracyhorizontal>10.0</accuracyhorizontal>
<accuracyvertical>4.0</accuracyvertical>
<al>5.7</al>
<nr>96</nr>
</wpt>
<wpt lat="52.32835728" lon="5.05861943">
<datetimegps>2015-10-01T06:27:33.196</datetimegps>
<datetimearrivedincode>2015-10-01T06:27:33.203</datetimearrivedincode>
<datetimeprocessed>2015-10-01T06:27:33.275</datetimeprocessed>
<c>138.4</c>
<s>26.5</s>
<accuracyhorizontal>10.0</accuracyhorizontal>
<accuracyvertical>6.0</accuracyvertical>
<al>5.9</al>
<nr>97</nr>
</wpt>
<wpt lat="52.32802075" lon="5.05960610">
<datetimegps>2015-10-01T06:27:32.905</datetimegps>
<datetimearrivedincode>2015-10-01T06:27:33.246</datetimearrivedincode>
<datetimeprocessed>2015-10-01T06:27:33.283</datetimeprocessed>
<c>119.2</c>
<s>26.3</s>
<accuracyhorizontal>10.0</accuracyhorizontal>
<accuracyvertical>4.0</accuracyvertical>
<al>5.3</al>
<nr>98</nr>
</wpt>
On the map:
Note: A and C are on the exact location, I changed them manually to show A is behind C.
The following is weird:
Point 3 means I cant just fix it by holding the last GPS date and skip everything earlier then the last one.
Total GPX file:
Zoomed-in at the problem:
Moved the double and incorrect order points next to each other:
Just reloaded the points im interested in with ABCD notations.
The GPX file from the above screenshot:
<?xml version="1.0" encoding="UTF-8"?>
<gpx xmlns="http://www.topografix.com/GPX/1/1" version="1.1" creator="flitsmeister-ios-app-test" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
<wpt lat="51.89792674" lon="4.54830456">
<tgps>2015-09-29T15:23:40.999</tgps>
<tv>2015-09-29T15:23:53.850</tv>
<c>131.8</c>
<s>13.1</s>
<ah>5.0</ah>
<av>3.0</av>
<al>2.0</al>
<nr>464</nr>
</wpt>
<wpt lat="51.89745789" lon="4.54927853">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:23:53.910</tv>
<c>125.9</c>
<s>8.6</s>
<ah>5.0</ah>
<av>6.0</av>
<al>5.4</al>
<nr>465</nr>
</wpt>
<wpt lat="51.89745789" lon="4.54927853">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:23:53.929</tv>
<c>125.9</c>
<s>8.6</s>
<ah>5.0</ah>
<av>6.0</av>
<al>5.4</al>
<nr>466</nr>
</wpt>
<wpt lat="51.89745789" lon="4.54927853">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:23:53.932</tv>
<c>125.9</c>
<s>8.6</s>
<ah>5.0</ah>
<av>6.0</av>
<al>5.4</al>
<nr>467</nr>
</wpt>
<wpt lat="51.89762654" lon="4.54890185">
<tgps>2015-09-29T15:23:44.999</tgps>
<tv>2015-09-29T15:23:53.933</tv>
<c>128.0</c>
<s>13.4</s>
<ah>5.0</ah>
<av>4.0</av>
<al>0.6</al>
<nr>468</nr>
</wpt>
<wpt lat="51.89745789" lon="4.54927853">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:23:53.965</tv>
<c>125.9</c>
<s>8.6</s>
<ah>5.0</ah>
<av>6.0</av>
<al>5.4</al>
<nr>469</nr>
</wpt>
<wpt lat="51.89755810" lon="4.54904694">
<tgps>2015-09-29T15:23:45.999</tgps>
<tv>2015-09-29T15:24:02.016</tv>
<c>126.9</c>
<s>12.5</s>
<ah>5.0</ah>
<av>4.0</av>
<al>0.2</al>
<nr>470</nr>
</wpt>
<wpt lat="51.89800163" lon="4.54815385">
<tgps>2015-09-29T15:23:47.731</tgps>
<tv>2015-09-29T15:24:02.068</tv>
<c>132.9</c>
<s>12.8</s>
<ah>5.0</ah>
<av>4.0</av>
<al>2.3</al>
<nr>471</nr>
</wpt>
<wpt lat="51.89800163" lon="4.54815385">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:24:05.832</tv>
<c>132.9</c>
<s>12.8</s>
<ah>5.0</ah>
<av>4.0</av>
<al>2.3</al>
<nr>472</nr>
</wpt>
<wpt lat="51.89749909" lon="4.54917803">
<tgps>2015-09-29T15:23:46.999</tgps>
<tv>2015-09-29T15:24:05.842</tv>
<c>126.9</c>
<s>10.8</s>
<ah>5.0</ah>
<av>4.0</av>
<al>8.4</al>
<nr>473</nr>
</wpt>
<wpt lat="51.89800163" lon="4.54815385">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:24:06.289</tv>
<c>132.9</c>
<s>12.8</s>
<ah>5.0</ah>
<av>4.0</av>
<al>2.3</al>
<nr>474</nr>
</wpt>
<wpt lat="51.89745789" lon="4.54927853">
<tgps>2015-09-29T15:23:47.999</tgps>
<tv>2015-09-29T15:24:06.307</tv>
<c>125.9</c>
<s>8.6</s>
<ah>5.0</ah>
<av>6.0</av>
<al>5.4</al>
<nr>475</nr>
</wpt>
<wpt lat="51.89732735" lon="4.54958171">
<tgps>2015-09-29T15:23:52.999</tgps>
<tv>2015-09-29T15:24:06.339</tv>
<c>121.6</c>
<s>2.9</s>
<ah>5.0</ah>
<av>4.0</av>
<al>-2.3</al>
<nr>476</nr>
</wpt>
</gpx>
In this file the problem occurred a couple times but seems to locate at 2 problem locations. After that no problems more but the user killed the app after a some KM.
Don't set pausesLocationUpdatesAutomatically to FALSE. It's default TRUE and for a navigation app it should stay TRUE. You will get a lot more locations when you set this to FALSE, locations that are no different to another one.
Set properties on the CLLocationManager once, when you change properties to often weird and more locations will arrive at the delegate. In example: if you set these properties in the delegate method didUpdateLocation you will end up with 4 locations on the exact same millisecond.
_manager.desiredAccuracy = kCLLocationAccuracyBestForNavigation; _manager.activityType = CLActivityTypeAutomotiveNavigation;
753
I finally figured it out. The following things where wrong:
I had another CLLocationManager in my project running this code each second:
[locationManager startUpdatingLocation]; if([locationManager respondsToSelector:@selector(allowsBackgroundLocationUpdates)]) { locationManager.allowsBackgroundLocationUpdates = TRUE; }
I was setting properties on the CLLocationManager more than once. When you change properties too often, weird and extra locations will arrive at the delegate. For example: if you set these properties in the delegate method didUpdateLocation you will end up with 4 locations on the exact same millisecond.
_manager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
_manager.activityType = CLActivityTypeAutomotiveNavigation;
We have found out that one test user had his GPS chip broken or something. For some reason his device reported wrong GPS coordinates occasionally. Make sure at least two users are reporting an error! At some point when we fixed point 1 and 2, this user had this error but all other users were OK. Later on he also reported errors with the store version (which was build with iOS8).
Don't disable pausesLocationUpdatesAutomatically (set it to false). It defaults to enabled and for a navigation app it should stay enabled. You will get a lot more locations when you disable this, locations that are no different to another one.
So yes, there is a big difference between iOS8 and iOS9. If you experience weird locations check these points above.
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