The authors wrote a client to ask Apple’s WiFi Positioning API for the locations of random AP addresses. Enough of the random addresses were known to Apple’s lo

The authors wrote a client to ask Apple’s WiFi Positioning API for the locations of random AP addresses. Enough of the random addresses were known to Apple’s location database that it returned real location data. Apple’s API also returns the addresses and locations of 400+ other nearby APs. That enables iOS devices to do faster and offline content geolocation in the same region. > Apple’s API will return the geolocations of up to 400 hundred more BSSIDs that are nearby the one requested. It then uses approximately eight of those BSSIDs to work out the user’s location based on known landmarks. > In essence, Google’s WPS computes the user’s location and shares it with the device. Apple’s WPS gives its devices a large enough amount of data about the location of known access points in the area that the devices can do that estimation on their own.