Despite the digitization of maps and the satellites circling the earth, the cartographic revolution still relies heavily on fresh test observations made by people.Navteq, like Prince Henry, produces updates periodically (usually four times a year for its corporate 30 clients. Its explorers are its geographic analysts These people go onto the roads to make sure everything that the satellite data says about those roads is true to check the old routes and record the new ones. The practice is called ground-truthing. The analysts drive around and take note of what they call "attributes which are anything of significance to a traveler seeking his way. A road segment can have one hundred sixty attributes, everything from a speed limit to a drawbridge, an on-ramp, or a prohibition against U-turns.