An exclusive look inside Ground Truth, the secretive program to build the world's best accurate maps.

Behind every Google Map, there is a much more complex map that's the key to your queries but hidden from your view. The deep map contains the logic of places: their no-left-turns and freeway on-ramps, speed limits and traffic conditions. This is the data that you're drawing from when you ask Google to navigate you from point A to point B -- and last week, Google showed me the internal map and demonstrated how it was built. It's the first time the company has l