Passbook location services clarification (battery life)

Discussion in 'iOS 6' started by jonahsaltzman, Oct 5, 2012.

  1. jonahsaltzman macrumors newbie

    Jul 29, 2011
    Is having a location-aware pass the same as leaving the maps application open 24/7...? The solid location services icon seems to indicate that.

    After trying to figure this out in other threads, I think we need a thread where someone can clarify how the location-based feature of passbook - where your starbucks card shows on the lock screen when you're near a starbucks, etc. - works. Apple lists two kinds of location services: geofencing, shown as an outline of the location services icon, and regular, shown as a solid icon.

    Passbook does not seem to use geofencing - under the privacy/location services menu, apps like Reminders have the outline icon (geofence) but passbook definitely has a solid icon.

    I'm not sure about anyone else, but when I have a pass in passbook using location services (starbucks, in my case), whenever I wake the phone up from standby, there is a solid location services icon at the top. It stays there for ~10 seconds, then goes away. I checked the list of apps that use location services, and the only one with a purple arrow (meaning used found location services) was passbook, so I know that the icon I see when I wake up my phone is due to passbook.

    My question is this: do you think that location services is ALWAYS on while the phone is locked? Won't that be terrible for battery life? I suppose it's possible that it only checks your location when you wake from standby, but then you'd have to wait a minute after you take out your phone for the pass to show up.

    Are there different resolutions of location awareness that are all represented by a solid location services icon? Because maybe passbook uses a less accurate (and less power-hungry) service just to tell if you are within, say, a block or two of a starbucks.

    Does anyone know how this works?
  2. Rigby macrumors 601

    Aug 5, 2008
    San Jose, CA
    Well, only the developers know for sure. But based on my highly scientific analysis ;) I believe Passbook only checks the location when you actively turn on the device. Evidence: Differently from location-based reminders (which use the iOS geofencing mechanism), location-based Passbook notifications do not light up the screen on their own. Also, it takes a moment after turning on the phone in the tagged location until the Passbook notification pops up.

    But more importantly, I've had the Starbucks card active for a day now and I do not see decreased battery life. I'll keep an eye on it for a while, but I think it's just fine.
  3. xraydoc macrumors demi-god


    Oct 9, 2005
    I've had the Starbucks pass in my Passbook for the last couple of days. 6 favorite locations are set in the pass. I do not have a solid nor outlined Nav indicator in my status bar at all. And battery life appears to be unaffected.
  4. waw74 macrumors 68030

    May 27, 2008
    I believe the phone always kinda knows where it is, based on cell towers, not to a high degree of accuracy though. not sure if cell towers are broadcasting coordinates or not.

    I live in NYC, i'm about 100 yards in a straight line from my starbucks, it's usually on my home screen when i'm in my apartment.
    tonight i was at a bar, and was about 250 yards from another starbucks i go to if i'm on my way to work, and that was on my screen.

    my friend who lives about 250 yards from the same starbucks, said it was on his screen while he was at home also.

    if i turn on maps and find my location which activates the GPS, it goes away for a while.
  5. Rigby macrumors 601

    Aug 5, 2008
    San Jose, CA
    Turning on Wifi should give you much better accuracy. The GPS chip is useless indoors unless you sit directly by a window.
  6. waw74 macrumors 68030

    May 27, 2008
    i have wifi on

    I'm talking about when the phone is sitting there in you pocket or on the table or if you're using it, but not actively requesting location information.
    The GPS isn't active, but the phone is aware of it's basic location.
    once you do things that request location, like launching maps, the GPS turns on and gives you a more accurate location.

    the post is about location services drain on battery, the GPS isn't active normally, so it's not draining the battery. It's using basic communication with the cell towers, which the phone is already doing in the background to keep the telephone part working. which is much less accurate than GPS.
  7. Rigby macrumors 601

    Aug 5, 2008
    San Jose, CA
    What I was trying to say is this: As soon as you wake up the phone, Passbook checks the current location to see if it is in one of the activation areas defined by the location-based Passbook cards. From what we can tell it uses the regular iOS location service for that (indicated by the icon), which uses all available means to do that (known cell towers and wifi hotpots, and GPS if you have line of sight to the sky). If you have Wifi on and a known access point near you, you should quickly get an accurate location and thus no misleading Passbook notifications when you are far away from the activation area. The fact that you do seems to indicate that the phone cannot get an accurate location fix in your case for some reason.
  8. urkel macrumors 68030

    Nov 3, 2008
    Maybe it's using Apple Maps. </zing>
  9. kas23 macrumors 603


    Oct 28, 2007
    Yes, maybe it is just checking your location during the first few seconds of you waking your phone. If this is so, then I really can't see this having any noticeable effect on battery life.
  10. philip in al macrumors regular

    Jun 23, 2010
    But if you look at my other thread, you'll see that it actually checks your location every single time the lock screen comes on. This means every time an email alert or any other alert makes your screen come on.

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