I am a mobile app developer developing a pair of iOS apps that use device location for search, and I’m trying to put constraints on the dimensions necessary for a cells in a quadtree-based location mapping system. The minimum cell size should roughly coincide with the margin of error for an iPhone or iPad with “use precise location” turned off.

Yes, I realize this likely varies by iPhone and iPad model, so if you can answer this question, please let me know which model(s) the statistics are for. I am interested in finding this information about models from the last 5 years or so. And I’m mostly interested in the margin of error for when precise location is turned off.

Does anyone know or know where I can find data on the precision of iPhone/iPad locations (i.e. a margin of error, as a range, in meters), for both precise location turned on and precise location turned off?