GPS is amazing technology. Radio signals sent from a couple dozen Department of Defense satellites circling the earth at about 7,000 MPH are picked up by receivers in your car dashboard or portable GPS navigator. Triangulation of three signals allows the units to pinpoint your precise location on the planet. Cool.

Of course what many GPS users want to know is not their location on the Earth but rather their location on the human landscape. They want to find an address, or know whether to turn right or left at the next intersection. They want to know where the nearest gas station, restaurant or hospital is located, and the fastest way to get there.

GPS Map Updates

Getting there requries a map, or multiple maps with multiple layers of information. When you buy a GPS unit it comes with mapping software preinstalled. The geographic information stored in your unit probably wasn't collected yesterday, or even last year. In fact...well, when was it collected?

Remember, digital GPS maps have no way of updating themselves. They're created through on-the-ground surveys--people out actually driving the road network and collecting data. So while the helpful voice speaking to you from your car dashboard seems to know exactly where you are, remember that your navigator is "seeing" the world as it was at some time in the past--maybe five years ago, or whenever was the last time the guys in the van with the funny antenna passed through your area. That can sometimes cause problems.

The best you can do is to keep your dashboard or portalbe GPS updated with the latest maps available. Customers have been demanding more frequent and less expensive updates for a long time, and improvements have made. Garmin and the rest are putting out GPS update packageson a pretty regular basis, but there's always a significant lag period between changes occuring on the gound and your GPS navigator knowing about them. First a new survey has to be scheduled and carried out by the companies that do the actual mapping. Eventually he new data is acquired by GPS manufacturers, formatted according to their specific requirements, and made available for distribution.

To keep up with the latest GPS map updates, check first on your manufacturer's website, but also check GPS forums and information sites such as GPS Update Center. And don't forget sites like Ebay and Amazon where you can sometimes find GPS update maps on DVD at discount prices.