Logging into Google Maps builds more of a complete travel landscape than one might think. After checking this article and logging into the google maps chart, you will see Google Maps and logged in users are certainly tracked.
You can see a day by day chart of your location history with google by logging into said location history page on Google. This has been one of those theories I had for some time, but seeing the charts vividly prove the suspicions is really surreal. It also appears that some triangulation occurs by cellular towers, as I keep my GPS function off most often to preserve battery.
Interesting stuff indeed. Lots of power and money in that tracking data, I am sure. Please give these charts a read, if you doubt the level of tracking in the world today. Because the proof is in the pudding.