Navigation is an essential feature of any hiking trip and, while you should certainly master the old-fashioned skills of working with a map and compass, modern hand-help GPS systems, which no longer cost and arm and a leg, can also come in very handy.

The Global Positioning System (GPS) is fast becoming very much an everyday navigational tool and is commonly seen fitted into cars these days. It is also now available in a simple hand-held form, similar in size to many cell phones.

A GPS unit can be loaded with map data for just about any area of the world and, by using a series or satellites, it can pinpoint your position with remarkable accuracy. Indeed, many units can not only indicate your position on the ground, but can also provide you with an altitude reading.

Like most things, GPS units are priced at a reasonably low level for a basic unit which will simply give you your latitude and longitude, to extremely expensive units which are packed with more features than the average hiker could ever possibly use. For this reason it's important that you decide just exactly how you want to use a GPS unit before you go shopping.

The world's leading manufacturer of GPS is Garmin and you will certainly find a range of Garmin units on sale in just about every outlet, including of course outlets online. There are also other brands of course and, whichever brand you choose, you'll find a bewildering range options available in different shapes and sizes.

For the hiker it's particular worthy of note that some models are waterproof, which can come in very handy if you're likely to be crossing rivers and lakes or if you get caught out in a storm.

Different models also offer different numbers of waypoints. A 'waypoint' is simply another term for terrestrial coordinates such as latitude, longitude and altitude. For most hikers these basic waypoints will be sufficient but, if you're into gadgets, you might like to check out the variety of other waypoints that can be used to indicate your position on the ground.

You will find that when talking about GPS units the term 'waypoint' is also used to describe the number of landmarks shown on the display. This will vary depending on the map that is loaded into the unit and the amount of information displayed can be both good and bad as far as the hiker is concerned. While it might seem that 'the more information the better', too much information can simply become confusing and actually make the job of navigation more difficult rather than easier.

One popular Garmin model with hikers is the eTrex which is lightweight, waterproof and displays up to 500 waypoints. It also has a number of controls along the side which allow you to control the size of the display, including such things as zoom.

The majority of units fall into the $100 to $300 price range, although units can of course be purchased at well in excess of $300. In the GPS arena, like most others, you often get what you pay for and you're probably looking at somewhere around $200 for a good unit that is suitable for hiking.

One thing to look for is a unit that will work in a 'static' environment, as some units require movement in order to give you a reading. It can also be useful to buy a unit which provides an altitude reading as this can be very useful in hilly areas when contour lines on the map can be confusing.

The secret to buying a GPS unit is to think carefully about how you will use the unit and then to do some research and look at a lot of models before making any purchasing decision.