They can be set to receive data across varying number of channels, usually 12-16. The general rule is the fewer channels, the harder the unit has to work to find the satellites.  You can use them not only to help you navigate, but you can also store your favourites routesif your memory is sufficiently large. Many GPS units these days will plug into your PC at home to allow you to download routes from digital route mapping software such as Track Logs or Memory-Map.

There are a couple of things to look out for when choosing a GPS receiver, firstly, the screen quality, as the data you’ll be viewing might be quite small and detailed so the higher resolution and the larger the viewing screen the better. Secondly, the battery life. If you intend to take your GPS on a long hike you really won’t want it dying on you part way along.   You can get an external power unit with some receivers, but that’s an extra thing to carry.

A final tip is to check the receiver is set up to match the coordinates system that is on your map to avoid getting completely confused and lost!