PDA

View Full Version : How does location function in Google Maps work with WiFi?




iwannamac
Apr 3, 2009, 07:41 AM
When I press the location feature in the Google Maps app on my 1st gen touch while at home, it is able to pinpoint my location correctly at an accuracy down to my address (based on the "sight" that appears). How does this feature work? I've traced my IP before, and it's only accurate to the city next door. Just curious.



edesignuk
Apr 3, 2009, 07:43 AM
It "knows" the location of fixed public wifi points and figures it out from there....I think.

iwannamac
Apr 3, 2009, 10:13 AM
Interesting. I'm not aware of any public wifi areas near me. It works like a charm, though.

goosnarrggh
Apr 3, 2009, 11:23 AM
Interesting. I'm not aware of any public wifi areas near me. It works like a charm, though.

The service used by the iPod touch is powered by a company called SkyHook.

SkyHook does not restrict itself to "official" public WiFi hotspots. Instead, it sends a fleet of vehicles down every navigable street within a covered area, scanning ALL of the WiFi access points in the vicinity (both private and public) and recording their unique signatures (called a MAC address, but it has no relation to the popular computer platform) along with their signal strength at various latitudes and longitudes.

Whenever the WiFi radio is turned on and CoreLocation is in use, the iPod touch continually scans the MAC addresses and relative signal strengths of all the WiFi access points in the vicinity (not just the one it happens to be connected to), and queries those MAC addresses in SkyHook's database. It can then use those results to triangulate your approximate location.

If SkyHook's database doesn't contain an entry for the WiFi access points nearest you, or if the WiFi access point has moved since the last time SkyHook refreshed its database, then the iPod touch will provide incorrect location information. In that case, it is also possible for operators of WiFi access points (including owners of private home networks) to submit new information to SkyHook in order to help them improve their coverage.

sandman42
Apr 3, 2009, 05:18 PM
The service used by the iPod touch is powered by a company called SkyHook.

SkyHook does not restrict itself to "official" public WiFi hotspots. Instead, it sends a fleet of vehicles down every navigable street within a covered area, scanning ALL of the WiFi access points in the vicinity (both private and public) and recording their unique signatures (called a MAC address, but it has no relation to the popular computer platform) along with their signal strength at various latitudes and longitudes.

Whenever the WiFi radio is turned on and CoreLocation is in use, the iPod touch continually scans the MAC addresses and relative signal strengths of all the WiFi access points in the vicinity (not just the one it happens to be connected to), and queries those MAC addresses in SkyHook's database. It can then use those results to triangulate your approximate location.

If SkyHook's database doesn't contain an entry for the WiFi access points nearest you, or if the WiFi access point has moved since the last time SkyHook refreshed its database, then the iPod touch will provide incorrect location information. In that case, it is also possible for operators of WiFi access points (including owners of private home networks) to submit new information to SkyHook in order to help them improve their coverage.

This is the best and most accurate explanation I've seen. Well done.

indy42
Apr 3, 2009, 07:22 PM
SkyHook? Hey, me and Batman got something in common!

Brewerpaul
Apr 5, 2009, 08:27 AM
Pretty cool, but note that keeping location ON uses up battery power more quickly, so you may want to keep it OFF unless you really need that feature.

iwannamac
Apr 5, 2009, 08:29 PM
The service used by the iPod touch is powered by a company called SkyHook.

SkyHook does not restrict itself to "official" public WiFi hotspots. Instead, it sends a fleet of vehicles down every navigable street within a covered area, scanning ALL of the WiFi access points in the vicinity (both private and public) and recording their unique signatures (called a MAC address, but it has no relation to the popular computer platform) along with their signal strength at various latitudes and longitudes.

Whenever the WiFi radio is turned on and CoreLocation is in use, the iPod touch continually scans the MAC addresses and relative signal strengths of all the WiFi access points in the vicinity (not just the one it happens to be connected to), and queries those MAC addresses in SkyHook's database. It can then use those results to triangulate your approximate location.

If SkyHook's database doesn't contain an entry for the WiFi access points nearest you, or if the WiFi access point has moved since the last time SkyHook refreshed its database, then the iPod touch will provide incorrect location information. In that case, it is also possible for operators of WiFi access points (including owners of private home networks) to submit new information to SkyHook in order to help them improve their coverage.

Wow, awesome reply. Thanks much!

cmichaelb
Apr 5, 2009, 11:38 PM
The service used by the iPod touch is powered by a company called SkyHook.

SkyHook does not restrict itself to "official" public WiFi hotspots. Instead, it sends a fleet of vehicles down every navigable street within a covered area, scanning ALL of the WiFi access points in the vicinity (both private and public) and recording their unique signatures (called a MAC address, but it has no relation to the popular computer platform) along with their signal strength at various latitudes and longitudes.

Whenever the WiFi radio is turned on and CoreLocation is in use, the iPod touch continually scans the MAC addresses and relative signal strengths of all the WiFi access points in the vicinity (not just the one it happens to be connected to), and queries those MAC addresses in SkyHook's database. It can then use those results to triangulate your approximate location.

If SkyHook's database doesn't contain an entry for the WiFi access points nearest you, or if the WiFi access point has moved since the last time SkyHook refreshed its database, then the iPod touch will provide incorrect location information. In that case, it is also possible for operators of WiFi access points (including owners of private home networks) to submit new information to SkyHook in order to help them improve their coverage.

Thanks for the info...I knew some of this but still learned something.