Fell Walking - Navigation Equipment
Map and compass
Without any doubt, the most important navigation equipment you can carry is a map and compass.
The map must be detailed enough for walking - the OS Explorer Map series is ideal as its 1:25000 is ideal for walking.
The compass needs to be of the 'Silva' type - it works in conjunction with the map.
You then need to learn how to use these! And this is something you should do before setting out on the hills!
An excellent resource for learning all aspects of Mountain Safety, including navigation, is Hill Walking: The Official Handbook of the Mountain Leader and Walking Group Leader Schemes .
Alternatives to buying OS maps
Buying and carrying a large number of maps can be expensive and often the maps cover a far larger area than you need. One alternative is to purchase computer software that can be used to display and print the maps you need. In addition, the software can be used to create routes which can be uploaded to a GPS.
For Windows users, Memory-Map is an excellent piece of software which, when combined with Toughprint Waterproof Paper, can be used to print durable A4 sized maps that are far easier to carry than a full sized one. The paper is waterproof and tear resistant, which means it can be folded and stuffed in a pocket without fear of damaging it.
The main drawback of this is that the grid references may not be shown on the map. It is essential to write these onto the map as you'll need to supply a grid reference in an emergency.
GPS units are very useful, especially ones that display OS walkers maps. Many Smartphones have a built in GPS receiver and apps such as Viewranger make excellent use of them.
The only drawback with electronic devices is that they can (and do) fail or the battery may run low when you need it the most! Therefore, never rely on a GPS and always carry spare batteries or an external power source, such as a Powermonkey