I noticed that Frequent Location on iPhone seems to use much less battery than an app monitoring iOS Visits (https://developer.apple.com/reference/corelocation/clvisit).
Frequent location on iPhone can be viewed on the phone via Settings -> Privacy -> Location Services -> System Services -> Frequent Locations.
I would like to know if Visit monitoring service from CLLocationManager is the same as iOS Frequent location or is it on different system used by Apple. If Apple is using the same service why it does not have any impact on the battery?
The two APIs are intended for different purposes.
CLLocationManager API
This API is designed to inform your application of location information based on requirements which are indicated by your app. You may choose some specific conditions when your app receives location data, and your app will continue to receive that data until it is no longer desired. Think for example, the Uber app would request location data when opening the app so you can schedule a ride, and would keep requesting it as your ride approaches.
Frequent Locations / CLVisit API
By contrast Frequent Locations is different in that it does not consistently report location data to your app. Instead apps can indicate they want to know if a user visited a specific location, and if the user does then iOS will inform the application. Locations tend to be somewhat rough. This would be used in the example of the StarBucks app, when you arrive near a StarBucks the app may tell you about the nearby shop with a limited time sale to encourage you to stop in. For many of these apps, the user will generally select a pre-defined list of locations which they will mark as their "favorite" locations/stores and the app will use that data to notify the user.
Battery Life
Due to the difference in how both of these APIs operate the difference in battery usage becomes apparent. With CLLocationManager we begin and continuously report either an accurate/rough location to the app. GPS is normally used here in addition to cellular triangulation and wifi hotspot location data.
But with CLVisit, we typically only notify the app a single time upon the initial visit (or departure) of a desired location. Due to this iOS doesn't need to wake the app and do any additional processing if the current location isn't roughly gotten closer or farther away from where we are interested in reporting. The device can get a rough location using cellular triangulation and wifi hotspot location data. GPS is not generally needed for this level of location detail. Since your cellular radio and wifi are usually "always on" it doesn't drain any additional power to use these two methods for location detection.
But how can it use cellular and wifi to determine where I am?
Explaining how your device derives it's location from cellular or wifi signals is beyond the scope of this question. But here is an excellent post explaining a little about how that information is derived. How does Google know where I am? - security.stackexchange.com
Related
I'm getting current location,
In my app I want to know my location is from GPS or WIFI or cellular data. How do I check that ?
Is there any way to determine location source ?
Apple iOS uses
Assisted Global Positioning System (A-GPS)
Crowdsourced Wi-Fi
Cellular network search
to determine your location:
These three stages are used in descending order of priority. In other words, iOS first attempts to fix your location by using a GPS satellite link. If it is unable to acquire a satellite, iOS fails over to Wi-Fi. If you are not connected to a Wi-Fi local area network (WLAN), then iOS uses cell tower data
Apple uses all the non-GPS systems simultaneously with GPS, as part of A-GPS. To say it's falling back is not really an accurate description. Rather, while trying to get a GPS lock, it will use the other systems to get a rough idea of your location. Only if no GPS lock can be obtained, will the phone simply report what it knows from the other sources.
CoreLocation does not provide its source (or sources), but you can use some heuristics to guess.
Check the accuracy reported with location updates. A large range (e.g. 500+ meters) would indicate it's not a GPS fix.
Check which radios are available. If there's no cellular radio in the device, fixes must come from Wifi.
Check if the cellular radio is active. The device does not need service with available providers to use towers for a fix. Don't filter on that.
Those are my best guesses. If you really want this feature, you'll have to experiment.
Is it possible to get access to the frequent locations recorded on iOS devices, I'm trying to figure out where the user's home is without using backgrounding services in my own app itself.
You may not access frequent locations already recorded on iPhone. The basic rule is whenever you want to learn something about a user, you had to obtain an explicit permission first. And that makes a perfect sense to me, as a user.
This rule is equally applicable to all the bits and pieces of personal info like photos, address book records and locations. You have to initiate visit monitoring from your app, and you will have to obtain a permission to always use location services to initiate this kind of monitoring.
I am looking on developing a tourist application for a city, where when the user is near to a "place of interest" he could get a push (local) on his device.
For example, I would add 100 POIs on my app, and a 100 messages for every POI to show when the user is in range, e.g. "You are close to the Cathedral of.."
Is this scenario possible? Is it possible to check the users position e.g. every 10 minutes even when the application is killed, and when in range fire a local push? How much battery would it drain? If the user closes the GPS would it try to use 3G/wifi signal to get the position?
If yes could you guide me the right way on what I should read on the subject maybe some tutorials and articles?
that's indeed possible. You could use the aforementioned technique outlined in this post. You can extend this with using CLLocationManager:: startMonitoringSignificantLocationChanges to restart the process of listening to locations after the app has been killed. Depending on your accuracy needs there are many other optimizations that can be done regarding battery life, like checking more frequently when a user speeds up etc.
I have developed a library that handles these details for you (for both Android and iOS). The download includes an example application that demonstrates how to use it. Feel free to check it out.
Yes,that is possible.you need to have some "places" (co-ordinates or addresses) stored on theapp locally. Proximity to a stored "place" can be checked by Reverse geocoder.
Check this Wonderful SO Question , very similar to yours
This might be too late for your question, but for anyone else that needs it. GeoFencing is a good option.
Here is a video explaining what geofencing is http://academy.pulsatehq.com/7-things-about-geofencing
And if you are using Ionic platform, here is the link to the plugin
https://github.com/cowbell/cordova-plugin-geofence
GeoFencing will solve exactly your problem. Just create a bunch of geofence located at these tourist sites and when user enters within certain radius of these locations, user will get a notification.
Good luck
When the app is killed, what exactly would be receiving the location updates?
When in the background though, you can set up location updates based on both proximity and time.
Check How do I get a background location update every n minutes in my iOS application?
As for GPS vs. 3g/wifi, the user has the ability to either allow location services for an app, or not. iOS will then handle whether GPS or cell signal will be used to determine position. Read about the significant-change location service here. Using the significant-change service will use more cell location than GPS lock to determine position, and vice-versa for the standard location service. Also look at location accuracy to learn more about conserving battery.
How would I go about figuring the position of someone inside (or outside) of a given area (such as a building) using assisted GPS with IOS app?
Is it possible to have it accurate enough withing a few feet?
Is this the right way to go about it?
Is it possible to utilize more than one wifi connection in the calculation?
Your app can use the Core Location framework to determine the device location. Core Location will use whatever hardware is at its disposal to determine the device location to the degree that you request. For example, some devices have WiFi but no GPS; others have WiFi, GPS, and cellular radios. Future devices may have other location technologies built in.
The point is that as an application programmer, you don't worry about that. Instead, you say: "give me a location that's accurate to 100 meters" or "let me know when the device has moved from the current spot by more than 10 meters" or "give me the location with the best accuracy you can manage."
Again, take a look at Apple's Core Location documentation to get a better idea of how it all works.
If you're looking to track a device with, say, 1-meter resolution inside a building, you're not likely to get that from Core Location. There's been research on triangulating position using known locations of WiFi transceivers, but nothing that's implemented in any commercial smart phone that I know of. I don't believe that iOS gives you easy access to the data you'd need to do this, so it's probably not a possibility. You could, however, go the other way: program several WiFi receivers around the building to listen for any nearby devices, use that information to triangulate the devices' positions, and then make that information available via some web service.
I want to build an application that can set up a set amount of geo-fenced square regions across town, I know I could achieve this by enabling location in the background, and check those coordinates to determine if they are in my area of interest.
But that would mean receiving many notifications from the system and would hit the battery performance.
Instead I wondered if there was a new API or possibly an upcoming one that would let you set a geo fence and only be notified by the system if you're inside of that or close by, rather then monitor your location constantly.
Is that possible ?
I found the following question, but I can't find much else:
http://www.quora.com/Is-the-geo-fence-functionality-built-into-iOS5s-Reminders-application-available-as-a-public-facing-API
It would seem to me that there is something more to geo fencing then tracking the GPS and comparing to an array of points of interest. If I set the reminders app to remind me that I have to walk my roommates dog tonight when I get in, then I can see the location icon at the top of the screen.
If I open the multitasking bar and remove reminders, the location icon persists, indicating the phone is tracking me, but it's an independent task to the reminders app.
If I set up an application with background location tracking, and remove from multitask bar, the location icon disappears with the application. This makes me believe that there is or will be an API for geo fencing coming for iOS 5.x, this would allow apps to post an array of coordinates to the system and receive local notifications based on the proximity to those points.
Does something similar exist or not yet ?
Thanks
UPDATE FOR FUTURE USERS
There seems to be a limit of 10 regions per app that can be monitored at any time (my personal testing), as this is a shared resource.
Apple Documentation extract:
You should always be judicious when specifying the
set of regions to monitor. Regions are a shared system resource and
the total number of regions available systemwide is limited.
You should look at the startMonitoringForRegion:desiredAccuracy: method on CLLocationManager.