With the advancement of satellite communication and computerised technologies many hikers now carry a Global Positioning System (GPS) with them to aid them with accurate navigation. However, it is always worthwhile to have back-up knowledge and to understand how to navigate simply by using a compass.
Understanding the Basic Features of a Compass
Regardless of the cost and quality of a compass, they all come with 4 basic features.
The compass needle determines the direction of ‘magnetic north’ and it will always point in that direction. It’s usually red in colour to distinguish the north arrow from the south. The base plate contains a ruler and, used in conjunction with a map, it allows you to calculate your position and also to determine distance. The heading arrow is attached to this and it should be pointing in the direction you are heading so you always need to hold your compass so that this arrow is pointing in the same direction as where you want to go. The turnable housing on the compass contains north, south, east and west and the degrees. It is designed to be rotated so that you can alter your bearing to magnetic north.
How to Calibrate Your Compass
It is necessary to understand that ‘magnetic’ north and ‘true’ north are not the same. Magnetic north is where your compass will actually point to and true north is where north actually is. There is about 1000 miles between the magnetic north pole and the actual north pole itself but this distance between poles can vary depending on where you are located on the planet and is often referred to as the ‘magnetic declination’ so you need to adjust your compass depending on where in the world you are using it as the declination will vary from place to place and only through adjusting it can it be used accurately.
Most good topographical maps will tell you the magnetic declination by indicating both magnetic north and true north on the map in the form of two identifiable arrows. It will often also give you this information in degrees which makes it even easier to calibrate your compass.
You should place your compass on the map and line up the true north line with the heading arrow on the compass and then rotate the housing until it is in line with magnetic north. Then turn the map until the compass is pointing north along the magnetic north line. The map will then be aligned to true north.
Finding Your Location on the Map
Orienteering is the term used to describe the navigation from point A to point B using a map and compass and to determine your location, you have to perform what’s termed a ‘triangulation’. This involves identifying at least two recognisable landmarks that you can see in your location and which you can also identify on the map. You should firstly draw a line through and beyond the first recognisable landmark then, choosing a second landmark that is at least 45 degrees away from the first one, draw a similar second line on the map. Your position is, therefore, where both lines intersect. By following the same procedure with even more landmarks, your exact location can be pinpointed with an even greater degree of accuracy.
Now that you know your precise location, you can use your compass to keep you heading in the right direction. Place the base of the compass on the map with the heading arrow pointing in the direction in which you want to travel. Rotate the compass housing until the north line on the compass and the needle are lined up. The heading arrow will now point you in the correct direction and providing that you keep the north line and the compass needle lined up along the entire duration of your hike, you will be heading in the correct direction which will lead you to your chosen destination.