Some of my users ran into an issue where they couldn't fetch the location using Location Service.
In the screenshots they sent me, i noticed that the battery level was really low, like 2-5%.
My question is, does iOS stop the location service when the device is running out of battery?
Thanks
Enabling Low Power Mode (the one that turns the battery icon yellow) does several things to reduce the battery usage of your device. This probably includes the accuracy and refresh rate of the GPS.
If you're requesting a location with a high level of accuracy, the system might either take too long and timeout or just decide not to fulfill that request since the hit on the battery would be too much.
does iOS stop the location service when the device is running out of battery
It certainly might. The GPS is one of the highest power draws of all the sensors. Turning it off would make a lot sense. See also Apple's own statements about low power mode:
https://support.apple.com/en-us/HT205234
Note that if this is the case, it would hardly be an issue with your app. Your app might use a lot of battery, which could be a problem; but if location services itself is affected, all map/navigation apps would be affected.
Related
I would like you to give me your feedback on which method consumes less battery.
My app will run in the background and will wake up with location changes, so I would like to use the method that consumes less battery.
Any ideas on which one it is?
Thanks
Neither of these choices is responsible for more or less battery consumption.
In order for your app to be notified of any location update, regardless of whether it is for a region change or a significant location change, you must specify in your app's Info.plist file that you will require location-services in the background.
There are actually two relevant choices for location services: location-services or gps.
In order NOT to drain the user's battery, choose location-services. If you say your app needs gps background services, you WILL drain the battery because this will cause the GPS hardware (assuming it is present) to be enabled, and THAT is the cause of battery drain. When you specify location-services, the device uses the cellular radio (which is on anyway, assuming you have an iPhone) to pinpoint the location instead. Not as accurate as gps, but most apps don't need GPS accuracy. (If you do, then use gps, of course, but know the consequences vis a vie battery life.)
I recently wrote a test app all about this (and I wrote about it last week here) and what I found was there was no significant battery drain when I had several regions setup for monitoring and I specified location-services as a required background service.
I want to create an (game based) iPhone application which sends your GPS location on a specific time (like 3-5 times a day) to a server. I found an apple page explaining some functionality to run in the background like location, music and VOIP.
I need the GPS to be accurate on the meter.
Can someone help me with a small example?
It really depends on your usage of the location. If you monitor actively, kiss the battery of your user goodbye. Very detailed accuracy, even bigger hit to battery. The backgrounding of location is all or nothing as far as accuracy goes.
Less hit, less accuracy is -startMonitoringForSignificantLocationChange. May not be accurate enough for you.
Better depending on usage, region monitoring. Triggers event on entry or exit of defined region.
You don't have the benefit of accuracy and timed location based events. You can do it, but is going to require a lot more effort on your end.
While this is untested, I am planning an app with a similar need. My solution is that on a significant location change, the app will determine what interval exists between the update timestamp, and when I care to know the users location (5pm for instance). If that's below some threshold, it will go into startUpdatingLocation mode (full power, battery draining, which is why that threshold is important) and then, on each location update, check if that target time has passed. if SO, send the update to your server, and go back to monitoring for significant changes. The catch is that if it still requires some movement to trigger the significant change update...so it isn't a perfectly reliable solution, but it may work depending on how you're using the data
You can't "schedule background work". iOS doesn't allow it.
The solution is to set yourself up for notification on significant change (which is some hit to the battery, but it's not horrible), and then only DO anything with that at occasional intervals.
Question: Does the Significant Location Change background service drain battery easily? I'm trying to track longitude latitude readings when the there is a Significant Location Change. However, before starting, I just want to make sure that this doesn't drain the battery.
If the Location service described above does not drain battery, can someone recommend a way to store the location changes that would be battery efficient. My initial thought was to store the longitude latitude points locally on iPhone and then send the information to the server on a much less frequent basis (2 hours). Anyone have a better approach?
I'm trying to build a simple location tracking app that is battery efficient. Thanks all.
Significant location changes do not take any extra battery draining because the device uses information that the GSM system is working with anyway. It has to keep track of signal strength readings of multiple cell towers all the time anyway. Your app is only started/woken when certain criteria are met.
To conserve battery you have to watch two subsystems:
make sure that CoreLocation is turned off when you don't need it, GPS takes the most
make sure that you send location data to your server in bursts, to allows the transmitter to power down.
2 hrs might be too much because the user might be terminating the app and then the updates would never be made. Or if you implement an offline queue, they would only be sent next time the app is started. But that depends on your specific scenario.
It should be cellular tower triangulation, and not GPS location, which is more than enough for your needs. It shouldn't be battery heavy at all.Same with uploading the location, do it rarely and you are fine.
Edit: Confused Core Location with Significant Location.
I have developed an application for iPhone that runs in the background with GPS mode on. I need to ask the server if there are any new tasks for the user? Fir this purpose, I have added the code in the didUpdateToLocation method. Now the problem is that it consumes the battery very fast. Please guide me how to avoid the battery consumption. Also, I need to keep the location accuracy at best.
Also, is there any other way where I can communicate to the server even while the app is running in the background. Please help me, I will be really grateful.
It is impossible to get accurate location without using internal GPS in the current state of iPhone. Since essentially you are keeping the GPS alive during the running of the app (not sure if Multitasking API allows GPS calling in background though), it would consume lots of battery power without doubt.
In this case, you either have to avoid calling GPS as much, or live with coarse locations from the cellar towers. You can't have both frequent GPS results and nice battery consumption.
I'm looking into the new background location service options in the iPhone 4 SDK. It allows an app to run in the background and receive location updates from the device.
There are two methods offered. One is a battery intensive mode that continuously gets location updates. The second recommended method sends the app location updates when there has been a "significant location change".
Does anyone know what a significant location change might be? Is a 30 foot walk considered significant, or is a 10 block walk considered significant? I imagine it also depends on the accuracy of the location mechanism being used at the time.
I've recently done some field testing of the new background location service to get an idea of what constitutes a significant location update, what kind of accuracy to expect for the location hits and our general experiences using it.
The results are detailed in a fairly lengthy blog post:
iPhone Background GPS: Accurate to 500 meters, not enough for foot traffic
As Steve Jobs mentioned in the OS 4 introduction, the low power mode uses cell tower triangulation and does not activate GPS unit. Since the iPhone phone module needs to keep a connection to the cell network anyway, there should be no impact on battery life.
Since the precision of a location fix with cell tower triangulation is anywhere between a few dozen meters (in dense city locations) and a few miles, I think 30 ft is not a significant location change. I don't know the specifics, though (and as mentioned by the commenters, the Apple dev forums are the right place to talk about those).