GPS makes all sorts of navigation easier. When you have a GPS unit and an unobstructed view of the sky, you'll never be lost again. There are a variety of GPS devices for sale, and purchasing the right one that fits your needs will help guarantee that you get the most out of your GPS unit. A device that does not work well for your requirements will usually stay at home and not be used. This guide will help you pick out the right type of GPS for you so that you'll get years of employment from your GPS.

Step 1: Picking the correct type of device

To start, you need to know about the various types of GPS devices out there and how each can meet your requirements. The primary types of GPS devices are: vehicle, handheld, and PDA attachments. The type of GPS device you buy will vary dependent upon your requirements, and the features you should consider will vary based on the type of device you are purchasing.

Vehicle GPS devices are a lifesaver if you drive for a living or make trips to lots of different locations with which you are not familiar. Vehicle GPS systems often come with features that help make operating them in a car much easier: features like automatic route finding which tell you when and where to make turns so that you can keep your eyes on the road. Some vehicle GPS devices feature technology that makes them aware of real-time traffic-reports so that your route can be recalculated based on traffic conditions. If you plan on using your GPS primarily in your vehicle, you should consider a device designed specifically for this sort of usage as these units usually have larger, easier-to-read, screens than most handheld systems.

Handheld GPS units tend to be the most versatile type of GPS units available. They can be used when camping, walking, driving, really any place you can go. But, this versatility commonly results in a device that has fewer advanced features. Since the entire system needs to be portable, the screen size is commonly limited and this can make many features of a GPS (such as map visuals, route marking, breadcrumb trails, etc) more difficult to use than in a device that is fixed in a vehicle or that makes use of a larger screen on a PDA or computer. If you intend on using your GPS mainly for driving, the small screen may make it harder to use. If you intend on using your GPS when hiking, camping, or fishing, this is probably the best type of GPS for you.

GPS units that plug in directly to a laptop or PDA commonly depend on the computer or PDA for all of the advanced GPS functionality except for the collection of the positioning data from the GPS satellites. Since a significant amount of the functionality is moved to the computer or PDA, the GPS unit itself is often much cheaper than a stand-alone GPS device. However, if you intend to use your GPS for camping, in marine conditions, backpacking, or walking, bringing your PDA or laptop may make using your GPS device more trouble than it's worth. As such, GPS units that connect to other devices are more commonly employed in cars and for folks who navigate by foot in cities. If you are looking for the lowest cost GPS device available and you already already have a GPS-compatible PDA or computer, this may be the right option for you.

Step 2: Selecting GPS Features

Based on the sort of GPS unit your are getting, here are some features you should look at.

Accuracy -- As a general rule, GPS units are accurate to within 50 feet. If accuracy is something you value (perhaps you are laying out a course for a race and you really want to make sure you get the 5K distance correct), consider a device with WAAS (wide area augmentation system) since this doubles the accuracy of your GPS unit. This feature tends to be most useful in handheld units.

Address Finding -- Some GPS devices let you to enter a target street address. This is very handy when driving and is a feature most often found in vehicle GPS devices or units used in vehicles.

Automatic Route Finding -- This is often used in tandem with address finding. This feature sets up the GPS to tell you precisely where to turn to get to a pre-programmed final destination. This is an incredibly useful feature for vehicle units, or devices used in vehicles, since it allows you to use the device without having to take your eyes off the road.

Built-in Maps -- Lots of GPS systems come with maps that are built-in; for example, all of the United States. If plan to purchasing a unit with a built-in map, be sure you get a GPS for your area, especially if you are shopping on-line. Also, make sure that the map can be upgraded.

Compass -- Believe it or not, there are GPS devices that do not include a compass except for when you are moving above some minimum speed (usually faster than a hiking speed). But there are GPS units that provide true compass functionality even when stopped. This feature is usually most useful in handheld GPS systems.

Computer Compatibility -- If you are considering a GPS unit that connects to a computer (which is most of them), and you are using a non-Windows computer (like a Linux machine or a Mac) be sure that the GPS unit is compatible with the type of computer you have. Every GPS unit that connects to a computer will support a Windows machine. But compatibility with other operating system varies.

Downloadable Maps -- Most GPS devices allow maps to be downloaded onto them. This is very convenient for users who travel far-and-wide. It also makes it easier to purchase a GPS that has less memory since you can easily swap out the map to fit the area you will be in.

Expandable Memory -- If you are using your GPS device with maps, you will want to make sure you have enough memory to hold the number of maps you will wanted loaded in your GPS. As it is with computers, the same is true with GPS units: the more memory the better. Another option is expandable/swappable memory so that you can be sure you'll never run out of space.

Extended Battery Life -- If you are going to be getting a PDA attached or handheld GPS device, look closely at the battery life as this may be the limiting factor in using your GPS.

External Antennas -- Some GPS units provide for an external antenna to be attached. This is very useful in vehicle units where the satellite signal may be degraded by the unit being in a car. It can also be useful in handheld systems as it allows you to keep the unit packed but still be operational for things like breadcrumbs.

Traffic Alerts -- Some GPS devices include the capability to download real-time traffic information. If you reside in an urban area, this is an incredibly useful feature even if you are familiar with the area you are in. This feature tends to be available in vehicle systems and in computer/PDA attached units.

Water-Resistant/Proof -- If you are purchasing a handheld GPS system and you intend to go hiking, camping, fishing, boating, or doing anything outside with your GPS system, consider getting a unit that has some level of resistance to water. Also, know the difference between waterproof and water-resistant. Water-resistant indicates that the system can be exposed to small amounts of water but it can't be submerged. If there is a probability your GPS will be completely submerged, you need a waterproof GPS, not one that is water-resistant.