Google Web Geo Locations - How?

[Willie Trombone]

Following from this thread
http://mybroadband.co.za/vb/showthread.php?t=187972&page=2
I thought I'd open up a seperate discussion with the web dev gurus...

Ok, so Google employ wardrivers?
How do they know where my personal Wifi point is? I know I have done some wardriving for fun using free apps on the G1 Android - works great and outputs kml format showing all the points you passed along the way...

But how do Google get that info? At first I thought they might have access to the location of public Wifi points but it seems they actually know where my personal home wifi router is... here is how I came to that conclusion:

My LAN setup is simple:
http://mybroadband.co.za/photos/show...=12062&cat=500

When I click 'where am I' on PC1, it shows me a very general map of the whole town and estimates I'm in town somewhere.
With PC2, Google pinpoints me to my house - 1m accuracy. If I connect PC2 to the CAT5 LAN and do the same, it shows the general location again. Back on Wifi it's the specific location.

PC2 uses the same ADSL router and LAN setup (double Nat'ed) except that it uses Wifi to connect to the LAN. My access point is not setup to broadcast the SSID but somewhere down the line, Google knows where I am...

For the record I am in the Eastern Cape and not Port Elizabeth, so it's not exactly JHB CT or DBN...

Anyone care to explain how??

 

[dequadin]

Very interesting topic! I did a bit of quick research and I think I've figured it out.

So how does it work? When you activate the My Location feature, Google Maps asks your web browser for your location. Typically, your browser uses information about the Wi-Fi access points around you to estimate your location. If no Wi-Fi access points are in range, or your computer doesn't have Wi-Fi, it may resort to using your computer's IP address to get an approximate location. As you'd expect, the accuracy of My Location varies with your location, and in some cases, Google Maps may not be able to provide a location at all.

Full article here also look here and here.

Basically what they do is they use the known location of WiFi howspots to triangulate your position. Beause a WiFi signal only travels a small distance, they can get a very accurate estimate of your location, as apposed to using cell phone towers which gives a more general estimate.

 

[Willie Trombone]

Very interesting topic! I did a bit of quick research and I think I've figured it out.


Full article here also look here and here.

Basically what they do is they use the known location of WiFi howspots to triangulate your position. Beause a WiFi signal only travels a small distance, they can get a very accurate estimate of your location, as apposed to using cell phone towers which gives a more general estimate.

I can only assume that it is using Wifi to determine my location... but here is the problem...
The wifi points within my reach are not exactly hotspots...
there are one or two other points within range of my house, but all of them are private - i.e. neighbours / home use etc. As for triangulation - AFAIK while I am connected to my LAN, my wireless card is locked to the frequency of my access point. In my area, I am the only one operating on channel 6. Therefore I don't think triangulation is used at all - and as mentioned before, it would only work if the private hotspots in the area are on some sort of database.

I can only assume that Google have my personal Wifi point on the map.

New question for the community - is wardriving and posting the results on your website illegal or just considered unethical? How do you feel about it? Of course your point is broadcasting for the world to see, but how legal or ethical do you think it is to share this as public knowlege?

 

[dequadin]

As for triangulation - AFAIK while I am connected to my LAN, my wireless card is locked to the frequency of my access point. In my area, I am the only one operating on channel 6. Therefore I don't think triangulation is used at all - and as mentioned before, it would only work if the private hotspots in the area are on some sort of database.

Yes it is part of the algorithm

everal years ago, Skyhook developed a browser plugin called Loki that taps into a computer’s Wi-Fi chip, takes a reading of all nearby Wi-Fi access points, and uses Skyhook’s proprietary database of access point locations around the world to triangulate the device’s location. The Apple iPhone uses this Skyhook technology whenever its Safari browser or its built-in Google Maps application request location data.

<snip>
Google’s geolocation technology is similar in principle to Skyhook’s—it also depends largely on information about nearby Wi-Fi access points

Full article here SkyHook info here

Note how you can still get a list of available wireless network even though you are connected to a completely different network. You can also see this behavior in Windows, if you goto you wireless network screen, you can still see all available wireless networks even though you are connected to a different one...

I can only assume that Google have my personal Wifi point on the map.

Yes they probably do,

For information about the locations of access points, Google relies on crowdsourcing—it quietly gathers local readings every time someone uses a Google app on an iPhone or a Blackberry, or some other mobile device

They probably use this in addition to wardriving.

How do I feel about it, not really bothered at all.

 

[Willie Trombone]

Thanks dequadin - that last bit prolly did the trick to solve it for me... heh, so when I was wardriving with my Google Android mobile, I wasn't just satisfying my own curiosity but Google's too

Same for when I was on my run with my GPS cardio software.
Who would have guessed that when you use your smartphone for GPS / wifi you are sharing that kind of info!?