My Location WiFi

[Guest Chris Jenx]

I'm not sure how much this has been discussed and I couldn't find a definitive answer on-line.

Does anyone know how My Location works from WiFi?

We all know how it uses mobile masts to guess your location from its footprint and distance.

When at home with no GPS signal My Location is spot on even though I barely have a 2G signal.

If I physically turn off WiFi the 'Location' goes miles away from my house.. So it is defiantly using my / surrounding access points to determine my location (and fairly accurately at that).

I can take a good guess at when 'Connected' to my AP it will use its IP address to determine an location... Which is fine, but those Geo Locations are normally City based and not very accurate?

But if I disconnect from the access point its still within about 5 meters of my house, which is what I don't get, Because surely that means either my phone or Google is storing the relative locations of the WiFi point I was connected too and now it can see it, it can produce more accurate results?

Am I missing something here?

I suppose the real question is how do the WiFi points broadcast and know there own locations? (even when not connected to one)

[Guest Webreaper]

It's all based around a big DB of publicly accessible Wifi hotspots. A reasonably good explanation here:

http://forums.macrumors.com/archive/index.php/t-680122.html