Under the streets and satellite images there are layers of information that we don't see, but that make Google the giant to beat in the map business
There is much more behind Google maps than what you see. Streets, house numbers, intersections, satellite images are only the superficial layer of what its new satellites and the Google Car scattered around the world see on our streets: our American cousins tell us that they peeked at Atlas, the software through which the company's engineers put together the enormous amount of information gathered from the sky and from the roadway.
The Ground Truth project brings together fine algorithms and manual work, contributions from Waze users and traffic information inferred from the load on telephone cells, aerial images and Street View data. Through the information recorded thanks to this last service, for example, Google knows the location of the house numbers or the shops even when they have not registered in the database: the text recognition software reads numbers and signs and translates them into geolocated data on maps.
Not only that: also road signs as stops and one-way streets are extrapolated from Google Car photographs and integrated into map layers, invisible to ordinary users but useful in Mountain View for navigation directions. And when the algorithms alone do not make it (as in this case: turns and signals of precedence are often painted on the road surface and easy that an electronic eye if you let them escape) intervenes a team of operators trained. Google does not reveal the number, but thanks to them if all the pieces of the puzzle are in place.