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I found a similar question here but I still don't get it.

You see, I live in a small town and every time I check my IP location via online services or speed test websites, my location appears to be my ISP server location (which in my case is 250 miles away). But when I tried Google latitude, it pinpointed my exact location within less than 100 meters!

I use Windows Vista, Google Chrome, and when I got the message that "Google is trying to locate you", I agreed just to check what the result will be. It was scary, very scary!

What I've come up after reading the above link is that Google have a kind of extensive WiFi database locations. That could be understandable with the case of public and open WiFis that are used with a lot of people. Some of them might be using applications that could gather location data and somehow this information ends up in giant Google databases. From those, Google could pinpoint a WiFi location based on its MAC address along with these bits of info that have been gathered via various sources.

The issue here is that my WiFi is private, I don't even broadcast my WiFi name. So how on earth did Google find my exact PC location?

Please break down the answer in layman's terms as possible.

Update:

I think that I found how they did it. First, we don't have google street view in the whole country, so the possibility that google obtained wifi info through that mean is not there. Second, when I tried the latitude, I did it using Google accounts belonging to me (for experimenting how it work). The first account, I used it in my PC. The second account, I used it in my cellphone which has GPS and was connected to the same WiFi that my PC was connected to. When Latitude got the cellphone location, subsequently it got hold of the WiFi location with its MAC address, hence the PC location since it was connected to the same WiFi.

I just need a confirmation if what I think is reasonable, I'm just a novice guy. :-)

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2 Answers

First, just because your SSID is not broadcasting, that does not mean you are not emitting radio transmitter waves. That said, they do not seem to use that when you are doing it from a browser. Here is the exact explanation of how they do it when you use a browser:

http://en.wikipedia.org/wiki/W3C_Geolocation_API

Of course, when installed on a phone, I believe every phone today comes with a locator.

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When Google made pictures for "Street View" they also collected data about available wireless networks. Cellphones with the Android operating systems can use this data to determine their location via "Assisted GPS" (faster than traditional standalone GPS) and they also transmit information about available wireless networks back to Google.

Although you have hidden your SSID (="Wi-Fi name"), each Wi-Fi-router has a globally unique "hardware address" called the MAC address. MAC means Media Access Controller and is not related to Apple's "Mac" trademark. Each piece of information sent from/to your router contains the sender's and the receiver's MAC address.


How Google finds you even without GPS:
"Google is trying to locate you" means: "Do you want to tell Google that you are connected to a wireless network with the MAC 10:9a:dd:2b:49:4d and that there is another wifi device nearby with the MAC 10:9a:dd:3b:3d:5f?"

If Google knows where one of the two devices is, then it knows where you are.

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aGPS does not use anything from Wifi. Read the link for details. –  Kevin Panko Mar 13 at 0:21
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