Significant Location Changes API does not report promised locations

Number:rdar://19000450 Date Originated:17/11/2014
Status:Open Resolved:
Product:iOS Product Version:
Classification: Reproducible:
Working on an application for a client, we observed issues getting location points. The general goal is to use SLC to track how much kilometres a user do in order to offer vouchers in client application (1km = 1point). Also the tracking is not supposing affect too much the battery usage.

To analyse the problem, we have recreated a sample application logging only the locations reported using Significant Location Changes (SLC) - see

Steps to Reproduce:
1. Install sample app and grant location permissions
2. Driving in a city (i.e. Berlin, Germany, see attached data) where cell towers coverage is intense
3. Analyse logged data (locations reported, compare with actual run).

- 2 Devices (SIM card with data plan)
/ same Urban track around Berlin
- Around 40 Km
- One device Standalone in background (Device 541, device locked, no power supply...)
- One device Standalone killed within the app switcher before starting the test run (Device 497, device locked, no power supply...) 

Expected Results:
We expected to get more and close location points (500m interval as documentation states) to determine the number of kilometres done.

Actual Results:
A map of presenting real drive done (GoogleEarth.kmz)
Each device folder contains the following data:
/ The app from the device (.xcappdata)
/ The log from the app (.log)
/ The console log (console_log)
/ An info summary ("Info.txt")

Only a hand full of locations have been logged on all devices. Even on the one which has been killed before test run.

iOS 7.x, see test data for accurate version

iPhone 5s



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