Using sonar in apps is nothing new...I suppose they probably just make a rough map of the area you're in and note the lighting properties and whatnot...ultimate

Using sonar in apps is nothing new...I suppose they probably just make a rough map of the area you're in and note the lighting properties and whatnot...ultimately you have probably spent some time outside or on wifi so they know approximately where you are and can narrow it down based on observations from other users.