Test your cell phone geolocation accuracy

[Joseph Elfelt]

FindMePro is a browser app that anyone can use to find out which settings on their cell phone or tablet produce the most accurate latitude longitude coordinates showing their location. I produced this browser app after discovering that my iPhone 4s sometimes produces coordinates with a good accuracy value but which in reality are wrong by several miles.

While you can try FindMePro on desktop and laptop computers, typically the accuracy will be very poor. FindMePro is intended to run in browsers on cell phones and tablets.

This app lets you:
1. Ask your browser to keep giving you your location coordinates while improving the accuracy.
2. Display the details for each set of coordinates on your screen.
3. Display each location on the Google aerial. Smaller circles indicate more accurate coordinates than bigger circles.
4. Adjust certain settings that are used by the app. For example, you could ask your browser to give you just a single coordinate instead of a stream of coordinates.

FindMePro browser app:
http://www.mappingsupport.com/p/findmepro.html

Typically when you tell this app to start collecting data the first locations returned are not very accurate and result in big circles on the map. Fairly quickly the accuracy should improve until the circles have a 5 meter radius.

About button
The app’s "About" button has more information on how you can test your cell phone to find out which settings on your phone produce the best and worst coordinate data.

Crowd sourced buttons
The two "Crowd Sourced" buttons have information on sharing your results so we all learn how to get the most accurate coordinates from our phones and how to recognize bad coordinates.

Two reasons for poor coordinate accuracy
First, certain settings on your phone can influence the accuracy of the coordinates your phone produces. Please read the text under the "About" button for suggestions on which settings you might want to test. Second, FindMePro tells your browser to only report coordinates for your current location and to *not* report any cached coordinates for any prior location. Some (all?) browsers ignore this instruction and sometimes report cached coordinates that can be wrong by several miles. For more information tap the "Crowd Sourced Results" button.

How to compare coordinates produced by other apps
1. Use FindMePro to collect coordinate data and display the map.
2. Tap Menu ==> Search
3. Enter coordinates from any other app into search bar at the top of the screen.
4. Tap Go
The map will center at the coordinate you enter. You can see how, that location compares to the green circles (last three coordinates) produced by FindMePro.

Offline use
Currently FindMePro only works if you are online. The browser technology needed to implement offline use is currently undergoing a major change (from 'appcache' to 'service workers'). After most browsers implement this new technology and it is stable, then support for offline use will be added to FindMePro.