Question on iOS geofencing implementation



Had a question regarding how Canary is implementing geofencing. This is sort of technical, so I’m not sure if I’m posting in the right part of the forum. Also, I am a little familiar with the iOS technical docs but I am by no means an iOS developer (though I am a software developer by trade, just not iOS specifically).

In the iOS settings screen for Location Services, there is a reference to “geofencing” at the bottom, where an app that has been using geofencing shows a purple outlined (but not filled in) icon. On the other hand, an app that has been using just plain “location services” will have a filled in purple icon.

I know that Canary says their app uses “geofencing”, but I have never seen the location icon in the Location Services screen displayed as the purple outlined version; it is always the filled in purple icon.

The reason I ask is that it appears the Canary app is constantly polling for a location in the background, and causing a slightly increased, but noticeable battery drain for me. I believe (but not 100% sure) that the iOS API allows an app to use “geofencing” instead of “regular” location services. Again, I am not an iOS developer and by no means an expert in their location services API’s. I am also not 100% sure if the API’s distinguish between “geofencing” and “regular” location services (along with any potential power usage differences), but this is just something that I noticed and was wondering about the implementation details, due to the battery drain I am experiencing.

Auto switching without GPS?

Hey @DualShock,

I think you might find this article on our Help Center useful to answer some of your questions:

How does Canary know when I’m Home or Away?

This articles goes into more detail about the various services we use to pinpoint your location for auto-mode switching. Feel free to ask any additional questions you may have beyond what is covered here!


Thanks @angie, that actually does help a lot!

The only other question I have is related to the location services icon in the Location Services screen in the iOS Settings app. I am just curious as to why the icon is always solid purple, as opposed to the purple outline used for geofencing, as shown below:


Hi @DualShock,

While we do primarily look at geofencing, this is just one of several Apple location “sensors” we’re using to determine your location. We also use active monitoring and look at significant location changes, which would cause that arrow to show solid purple as we would be using your location quite frequently.

Basically, the more of these sensors we look at the more accurately we can track when you enter and exit your home. If geofencing is failing to get results, we still have these other sensors as back up to make things as smooth and accurate as possible.

I hope that helps clarify things a bit!


Thanks @angie, that was a great explanation!


I read that the Canary will detect if your device is on the network and so will know if you’re home or not. Why do I need to keep GPS on my phone all the time which drains the battery very fast?


Hi @JoeyJoe,

I went ahead and moved your post to an existing topic we had about this. I think my answers to DualShock above also address your question, and will apply for both iOS and Android devices. If you have additional questions not addressed above definitely let me know!