How to navigate a GPS purchase

location based services

Driving cross-country or across town has never been easier. Once rare luxury items, navigational systems that use the Global Positioning System, or GPS, are increasingly affordable, but do your homework before buying. A GPS unit displays maps and step-by-step driving instructions, so you don't have to fight with a foldable map. As long as you're on roads in its map database, it always knows your exact location, so you're never lost. If you make a wrong turn, you'll know precisely how to correct it as long as it has the roads in its database. The companies that provide the mapping software used in GPS units send teams out on the road to keep abreast of new roads and other road changes. Caught in a traffic jam? Some models will suggest an alternate route, and some models incorporate up-to-the-minute traffic data that can help you avoid slowdowns from accidents or road closures. Traffic help sometimes means buying additional equipment or paying to subscribe to a traffic update service, however. Expect to pay as little as $100 or more than $1,500 for a portable GPS device. You'll find offerings from Garmin (www.garmin.com), Lowrance (www.lowrance.com), Magellan (www.magellangps.com), Navman (www.navman.com) and TomTom (www.tomtom.com). This is one gadget you'll want to try at a store so you don't get stuck with a model that is difficult to operate.Lately, GPS manufacturers have added extra features, such as the ability to play MP3, video and picture files. Don't be snagged by the bells and whistles. Here are some features worth considering: Portability. How you use your system should determine the model you buy. If you only want a GPS for one vehicle, a professionally installed model might be best. They're more expensive, but they look nicer; you won't have ugly wires all over your car's dash. If you own more than one vehicle or use rentals, a portable GPS can be quickly installed and removed using brackets with suction cups.There are even units for motorcyclists. The Garmin Zumo ($1,050) and TomTom Rider ($900) are designed specifically for two-wheeled vehicles. Display. You'll want a good color display easily visible in bright conditions. You want your eyes on the road, not concentrating on a screen.Screens 2 1/2-inches to 5-inches make for comfortable viewing. Larger screens are ideal for recreational vehicles. Smaller ones are fine for bicycles and motorcycles. Maps. Maps must be loaded into the GPS unit's memory. Some models store the information on a hard drive. You connect the unit to your computer through a USB cable and download the maps. Other units use memory cards. The maps are preloaded onto the card. Or, they can be downloaded to your computer and then inserted into the unit. Over time, maps need to updated. Check the cost. Updates can run as much as several hundred dollars.Directions. As the display gives a visual reference, GPS units announce when to turn. Some announce generic phrases such as, "in point two miles, turn left." But those instructions aren't too helpful. You have to look at the display to read the street's name. Units with text-to-speech technology are better. You'll hear the more specific instructions, "in point two miles, turn left onto 24th Street." The audio comes through speakers built into the units. Some models include FM modulators. This allows you to listen to the instructions over your car's stereo system. Software only. A personal digital assistant (PDA), Windows Mobile smart phone or a laptop can be turned into a GPS with the right software.Delorme (www.delorme.com) offers a variety of software packages bundled with a Bluetooth GPS receiver. Prices range from $150 to $1,000 and will run on Windows-based laptops and Palm and Windows Mobile PDAs and smart phones. The TomTom Navigator 5 is a Bluetooth GPS receiver and map bundle that retails for $300. It runs on Palm and Windows Mobile PDAs and smart phones.Microsoft Streets & Trips 2006 with GPS Locator (www.microsoft.com) combines Microsoft's mapping software with a GPS receiver. It retails for $130 and runs on Windows-based laptops. Contact Kim Komando at gnstech@gns.gannett.com.