Have you ever wondered where all the detailed information in GPS navigation systems comes from? So did we: So we took a ride out with Fred and Enrique, two field analysts for Navteq, who gave us insight into how they collect data to keep their maps up to date. Check out our slide show on cartography in the digital age.
The data collected by the Navteq analysts is used to supply and update mobile navigation device manufacturers, such as Garmin, Dell, and Thales, as well as vehicle navigation device manufacturers, including Alpine and Siemens, who in turn supply automakers such as Audi (pictured). Maps are updated every three months, with the latest version of each map database supplied to automakers and GPS device manufacturers for use in their latest products. Customers with older devices can receive map updates by DVD or through Web downloads.
Navteq has around 600 analysts scouring the nation's roads looking for updates and changes to existing maps. The company is in the process of switching all its surveillance vehicles to hybrid-engine cars like our Ford Escape Hybrid ride-along car.
Navteq uses a GPS satellite receiver, which is accurate to a range of three to five meters, and software from SAP Mobile Engine to plot road details. A PC in the trunk of the car is supplemented by a cabin-mounted computer, enabling the analysts to make changes in real time as they drive around.
Analysts are on the lookout for any of 200 road attributes, as well as any road work or related turn restrictions. They also monitor routes for any recently added points of interest. Navteq's POI database contains more than 14 million entries.
Navteq assigns an individual ID to each segment of road. In the city, each block has its own designation. As well as noting new roads, the Navteq crews are on the lookout for details such as speed limits, road dividers, turn restrictions, and speed bumps.
Analysts usually work in pairs: the driver takes voice notes using a microphone mounted above the driver's seat, while the front passenger uses a Pentab PC Tablet to note down changes directly on the existing Navteq maps.
Roads are classified according to their "function class" (FC), with each one given a rating from 1 to 5. Major roads, such as interstate freeways, are classified as FC1, while residential streets in suburban neighborhoods are classified as FC5. Typically, only FC1 to FC4 roads are considered by a GPS navigation device when plotting the fastest route. FC5 roads are used only if users wish to reach a destination by the shortest--rather than the fastest--route.