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Why do I need to turn on WiFi to determine my closest location?

For some reason, my mac won't get the latest time from the NTP server if I am plugged into Ethernet. What could possibly be different between my wireless and my Ethernet? Date & time window in OSX

Update: I let my Mac sit for 30 seconds with this window open, wifi off, and ethernet plugged in. The location and date would not update. Turning on wifi caused the location and date to be determined within seconds.

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I think you may have misread what the UI was trying to communicate. Turning on Wi-Fi is not mandatory just to get NTP working. All you have to do is select a time zone manually. Turning on Wi-Fi will allow your Mac to triangulate its location from nearby Wi-Fi APs in Apple's location database, which will allow it to set your time zone automatically based on your geographic location. It's just a helper, not mandatory. – Spiff Aug 26 '13 at 23:53
@spiff that was my though too. Even after letting the mac sit for a while, the location & time would not update. Immediately after I turned on wifi the time and location updated. – spuder Aug 27 '13 at 0:28
up vote 6 down vote accepted

Apple uses a database of WiFi network locations to determine your Mac's approximate location.

Quoting Apple's support article on Location Services:

Location Services allows applications and websites to gather and use information based on the current location of your computer. You have to give your permission before the application or website can use your location data.

Your approximate location is determined using information from local Wi-Fi networks, and is collected by Location Services in a manner that doesn’t personally identify you.

They used to rely on the Skyhook Wireless database, but since 2010 Apple runs their own, based at least in part on data gathered from iPhones (which have both GPS and WiFi and can therefore assign approximate physical locations to WiFi access points).

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Can you expand on this? Why does my home wifi device which is connected to my cable allows it to work but not being plugged in to the same network with an ethernet cable? I always assumed it was based on IP geolocation until I tried to use Yosemite maps on ethernet but this sounds like my wifi router is doing something else. – Yashua May 23 '15 at 1:48
@Yashua It's not clear what you're asking. If you have enabled Wi-Fi on your Mac, it knows about your own and neighboring Wi-Fi networks, and can match this with a database of known Wi-Fi networks and their physical locations. – Daniel Beck May 23 '15 at 10:26
So it's not my wifi router but my apple device that directly scans? But still, at some point we need an actual geo location - perhaps it eventually connects to a phone with wifi? And if I am alone in the woods connected to my wifi router would it fail? Curious about the specs/protocols. – Yashua May 23 '15 at 14:46
@Yashua Actual GPS or similar is not a feature of any Mac I'm aware of. That said, the density of iPhones and similar devices with Wi-Fi and GPS that send that data to Apple (and Wi-Fi networks themselves) is probably enough for a 90+% success rate by checking for Wi-Fi SSIDs from your Mac alone. – Daniel Beck May 25 '15 at 0:02

Not sure, but from the sound of what they are saying, you can choose an arbitrary location by nearest city - but this becomes static so if you move around, it may not be accurate. Alternatively, you can use Wi-Fi and it will appear to triangulate you. It is known that Google maps wi-fi routers to geographic locations and can use them to locate you. Not sure if Apple is doing the same.

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