CLLocationManager - Monitoring regions vs. Significant Location Changes

Question

I am currently using significant location change updates to monitor whether or not the user has entered a particular area of interest (my definition of an area of interest is more broad than can be defined simply by geographic regions). My requirements are that my app should be woken up periodically to check if the user is said defined area (if it is not currently running).

My question is: would registering for region updates (since I have a number of regions that are known to fit my area of interest), provide me with more updates than simply listening for all significant lcoation changes, or would they simply be duplicate updates? The reason I ask this question is to clairify whether or not region monitoring is simply a filter on significant location change updates (since neither are documented as powering the GPS), or if region monitoring somehow is able to be more specific (maybe it powers the GPS, but with more specificity). In particular, I would be interested to know if anyone has seen data or documentation on this issue.

Thanks.

Answer 1

Region monitoring seems to pull from more specific location signal changes than the significant location change service. I say this because I've defined small regions (~100 m radius) that region monitoring picks up in the background, but that Significant location change does not. However please remember that the two events are triggered on different types of user actions.

Region monitoring - triggered on boundary crossings only. So a user must have two location update events on either side of the boundary. If you define large regions and the user walks around inside of them you will get no updates.

Significant location change - Seems to be triggered on the phone switching cell towers and the Location Awareness docs seem to suggest that. Here is some great data on general accuracy of these updates that suggests about 500 m between notification.