Tracking multiple (20+) locations with iOS geofencing

Question

An iOS application uses the geofencing for notifying the user about predefined nearby locations. The application is allowed to miss some location (the user is not getting a

Answer 1

If you are concerned about performing the proximity check on each significant location change, you could use a spatial indexing/search method like R-trees or R*-tree to reduce the number of comparisons needed for each location change, as those search algorithms will filter out (possibly large) spatially irrelevant regions. That should reduce the time/battery power needed to perform the proximity checks.