Adel Youssef

First, what is GMM? Maps for mobile phones.

“My Location” shows blue dot with big circle giving idea of how accurate your location is.

Not GPS accurate, but very useful.

Why is “My Location” useful?

GPS free service, Free! Saves battery. no problem with line-of-sight. Many applications benefit from thie accuracy. No waiting for first fix. Works across many carriers and network types.

  • Collect geocontextual information along with a cell-id
  • Cell Tower Identifier (cell-id)
  • Location: GPS vs center of the map

Difficult to make it work across platforms and carriers, there is no unique ID across techs/carriers. How do we get location? If you have GPS cell phone, we collect that and the cell ID. We can also benefit from geo info like where you look at. Anonymous, just stores cell tower and location information, GPS or non-GPS.

We store this in our platform and run algorithms to figure out the location.

  • 100s of different platforms - causes many issues
  • Area of interest vs actual location
  • Noisy data
    • Oklahoma points
    • GPS errors
  • Towers in the water!

This approach can cause problems, if we’re all looking at SF maps the Burlingame cell tower will be identified as SF. Wherever you are, we often think you’re in Oklahoma because that’s the “center” of the US on google maps. GPS points can also be wrong if you have bad signal. Sometimes we find we have towers in the center of the ocean due to averaging, can be due to cell towers on oil platforms, which alters the accuracy. Sometimes that’s right.

Clustering Algorithm

  • GPS Clustering vs non-GPS
  • Use data diversity to calculat accuracy

Have invested more time in analysing the data. Data collection has been growing exponentially, working around the world, including the himalayas. Shows that this can work, non-GPS data is providing large amount of the data, more than GPS.

“Why doesn’t it work on my cellphone?”

We’re trying to get it working on as many as possible, some platforms don’t provide API to get cell ID. Some give part, so we do smart techniques to partly work it out. Some give multiple cell IDs. Others give full information.


  • A balance between respecting user privacy and providing good useful functionality to the user
  • How does My Location do this?
    • Anonymous: No PII, no session id
    • User has full control, can disable or enable it.

What next?

  • Improve accuracy and coverage
  • Continue improving security
  • Enabling location for 3rd parties via Android, Gears (browser)

Can use gears to enable it for your website or application. Build innovative location-based applications

Google Maps for Mobile with My Location - Behind the Scenes

Technorati tags: google, mobile, map, my-location, where, where2.0, where2008