About location precision or accuracyDepending on your device and available services, Location Services uses a combination of cellular, Wi-Fi, and GPS to determine your location. If you're not within a clear line of sight to GPS satellites, your device can determine your location using crowd-sourced Wi-Fi3 and cell tower locations.
Apps that display your location on the screen, including Maps, indicate your current (approximate) location using a blue marker. If your location can’t be determined precisely, a blue circle also appears around the marker. The size of the circle depends on how accurately your location can be determined—the smaller the circle, the greater the accuracy.This is from an I-phone website.
That's what it says on this website.