How To Buy Guide - GPS Guide

Like we mentioned before, combined with the right software, a GPS receiver can be a very powerful tool. Most GPS units use virtually the same basic technology – it's what they do with it that makes them different.

No matter which type of GPS device you're shopping for, you want to be sure it has features you find useful. Do you really need a fish-finder if you never go fishing? Here's a checklist of features to look out for:

Chipset – The best receiver on the market is currently the SiRF Star III chipset. It boosts GPS signal performance, making it possible to get better reception under trees, behind tall buildings, and sometimes even indoors. Also, make sure your GPS is WAAS (Wide Area Augmentation System)-enabled. This will help pinpoint your location to within 10 feet of where you're actually standing.

Display/Screen Size – Look for a GPS that has a bright, high-resolution screen (you want to be able to read it in sunlight without having to shade it). Most vehicle GPS devices feature 3.5- or 4.3-inch LCD touchscreens. Screen sizes on other GPS types vary.

Battery Life – Most GPS units ship with rechargeable batteries – a welcome change from the days of AA's. Some of them don't hold much of a charge, though. Be sure and plan according to what you'll be using your GPS for – if you're using it in the car, you might not need as long a battery life, but if you're hiking, you need a unit that will hold a charge for more than a couple of hours.

Maps – Make sure to get a GPS that has the proper maps installed. Most GPS units come with North American maps, and if you travel abroad, many come equipped with maps of different countries. Be sure to look for a unit that has the maps pre-installed on internal memory, so if the device has an SD card slot you can use it for other things.

Points of Interest – Also called a "POI," a Point of Interest is a location placemarker on a GPS. Most vehicle GPS units (and some others) come pre-loaded with a POI database, allowing you to find nearby hotels, gas stations, restaurants, and more. The least-expensive units ship with as few as 750,000 POI's, and the more expensive units can have databases holding up to 9 million POI's.

Text-to-Speech – This incredibly useful feature allows your vehicle GPS to read street names out loud. Most basic GPS units don't have this feature, and it's sometimes confusing to know when to turn (they tell you "Turn right in 500 feet," instead of "In 500 feet, turn right on Curtiss Place"). If you plan to use your GPS often, we'd highly recommend you look for a unit with Text-to-Speech.

Traffic – One of the best new features to come about in recent years. For a small subscription fee, many GPS units can now track traffic delays and direct you to a shorter route when necessary. If you drive in a city, you'll be glad to have this feature.

MP3 Player & Image Viewer – If you'd like to listen to music or view pictures on-the-go, this feature is for you. Most people already have an MP3 player that stores their music and images, so it's largely unnecessary to many users, but some people love it. An alternative is to look for a GPS receiver that integrates with your MP3 Player, so you can control everything from one place.

Bluetooth – If you have a Bluetooth-enabled GPS unit, you can pair it to your cell phone for a hands-free speakerphone when driving.

FM Transmitter – Some vehicle GPS units will transmit their audio through your FM stereo. While it sometimes makes it easier to hear the directions, it can be really tough to find a radio frequency with no interference in urban areas.

Built-In Compass – Most GPS units have a built-in compass. This is particularly useful in active and handheld/outdoor units.

Carrying Case/Dashboard Mount – Some GPS units come with a free carrying case; others make you purchase it separately. Most car GPS receivers come with a mount for your car. There are lots of different types, but most mount the unit to your windshield via suction cups. Be sure to investigate your state's laws – if they don't allow suction cup mounts, you might have to purchase another "bean bag"-style mount.

There are also a lot of fun "nice-to-have" features that are out there. Some units let you record your own voice, or choose celebrity voices, for directions. Others show you 3D images of complex interchanges. Still others offer "Where did I park?" features that help you locate your car in a crowded parking lot. While none of these are essentials, keep your eyes open when shopping for a GPS unit – you might find you can get cool features like this for only a little bit more.

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