Allessandro,
Did you click on that link he gave you in his post? If you zoom in on KORD, it shows the gate numbers painted on the ground, and the layout for the taxi lines leading into the gates crystal clear...better than Google Earth or anything else...very nice tool to use, yes? Also, click on the Bird Eye tab once you zoom into the airport and see how clear the photo's are...its like your standing in the control tower snapping pictures.