Using A Compass

The compass is the most important piece of equipment when out walking or on expeditions, it can save your life. Obviously combined with a map, life can be made easier, but with a map you can stop going in the wrong direction or around in circles. Once you are used to them they are easy to use and in poor weather conditions or unfamiliar country they are a welcome addition to anyone's personal equipment.

Choosing your compass

A compass simply uses a magnetic strip, carefully balanced and separate, that will simply point to (Magnetic) North. You should choose your compass with care. The most appropriate and easiest for use is probably the orienteering compass. A good one will have a well balanced steel magnetic needle that settles into position quickly. The needle will normally be coloured red at the north end. Some will have illuminous spots that glow in the dark. The base plate and dial are usually strong plastic. The dial will have increments of around 2 degrees marked clearly. On the dial itself will be faint meridian lines (faint parallel blue lines pointing in the same direction as north on the dial). Some even have extra information such as magnetic variation or declination degrees marked on the dial. The dial also has an arrow marked on the bottom aligned with north on the dial.

The base plate should be transparent and have scales in both metric and imperial. A magnifying glass, clinometer, sighting mirror and adjustable declination screw are all welcome extras. Don't forget a strong strap attached to the base, which should be securely held at the other end to your shirt pocket buttonhole or around your neck.

Bearings

A bearing is a 3 digit angle measured clockwise from north. It is a way of indicating direction without ambiguity. We usually speak of taking a bearing between 2 points, or the bearing of the pub from the church. We may need to use a bearing when the weather conditions are poor, or the surrounding landscape is unfamiliar or featureless. Then navigating by the map alone may not practical, and we may have to rely on the compass to tell us the direction in which we wish to travel. You may also need to take bearings when trying to pinpoint your position on the map by triangulation. Either way the process is quite simple once you get used to it.

To take a bearing between two points follow these steps. Note the two alternative methods at steps 1 and 4.

1. Leave the map as it is (in any old direction) OR [Set up the map so that it is facing north.]

2. Locate the point at which you wish to walk from, point A, (i.e. usually your current location) and the point you wish to walk to, point B.

3. Align the compass edge (assuming it is rectangular) so that it forms a line between these two points. Note that the compass should be facing in the correct direction (the direction of travel arrow should be pointing towards the place you want to go, the bottom of the compass is placed at your current location). If the compass is not long enough to do this, use a ruler or similar to join the two points and place the compass alongside this. The compass does not have to have the direction of travel arrow touching the two points (i.e. parallel lines will have the same bearing).

4. Rotate the dial so that the faint vertical lines on the dial itself align themselves with the vertical grid lines on the map OR [Rotate the dial so that the red marker on the bottom of the dial matches up with the red end of the north-south pointer]

5. You can now pick up the compass if you wish. Read off the number on the dial against the direction of travel arrow (there will usually be a small black marker to help you in this). This 3 digit number is the bearing of B from A. As always be careful about how many degrees each line on your compass represents. There are many different types with different markings, but usually each small line is worth 2 degrees with intervals of 20 degrees marked on the dial in writing.

6. If you wish to walk in a straight line from A to B, simply keep an eye on the compass and follow the direction of travel arrow. You must take care to ensure that the two red pointers (north-south and red marker on the bottom of the dial) remain aligned at all times.

Important notes on using bearings

When following a bearing do not just try to look at the compass and walk in a straight line. Even when trying hard to walk in a straight line on flat ground there is usually a natural tendency to deviate slightly and in any case, the landscape is hardly ever nice and flat. There will always be reasons to deviate off your intended path, that clump of trees, those holly bushes, that mountain spur. Even with flat ground and good 'seeing' it is very tiring to continually check your progress against the compass.

The best thing to do is to look along your bearing and notice a landscape feature that lays along that path. Then you can effectively forget about the compass and just make your way to that feature along the best possible root. Take regular sightings of the feature in case you lose sight of it during your 'detours'. When you reach the feature, simply take the same bearing again, (i.e. sight along the compass again) and repeat, looking for a prominent feature. With practice this is a very quick, yet still accurate method of travel. Of course it is not very effective in very poor weather conditions, at night, or in featureless landscapes, and there you will have to rely on regular checks on your compass. But for most situations it is effective.

Using your compass

Because a compass is based upon a magnet the needle can be affected by magnetic fields and materials such as iron. For instance your belt buckle, a zip, caribiner. Even mineral deposits in the ground can offset your compass. Don't just look down either. Look around and above you. Sitting under a power line or near an electric motor will not do you any favours. Never leave your compass sat on anything metal, as this will deteriorate the magnatism in the compass.

There are usually 3 different types of arrow marked on the compass. The vertical arrow marked on the front of the plastic base is your direction of travel arrow. This is the only arrow you ever follow.

The arrow that spins in the middle of the compass always turns to point north (the red end is the end that points north). NEVER follow this arrow, unless you happen to be going north.

The third arrow is the one that will be marked upon the dial. It is usually a red arrow marked on the bottom of the dial. This is the one that will match up with the red and white pointer that spins. When you want to read a number off the dial, look at the point where it touches the line at the top, this is the number you want.

NOTE: There are 360 degrees in a circle. Be careful about how many degrees each line on the compass represents. Normally on compasses of this type each line is worth 2 degrees. This is important as a difference of 5 degrees over a walk of 6 miles will mean you will be about half a mile from where you should be!

Compass Points

All you have to remember is the four main points of the compass. All the other points are made by combining these four. Some easy ways to remember the order of the points are to recall the following phrases. The points start at the top and go around clockwise.

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If you wish to quote a more accurate direction you can either opt for a more complicated compass point;

North by Northeast is a position halfway between north and northeast. Note that the convention for naming points of this type is to quote the 'more important' compass point first. For example, halfway between southwest and west would be called West by Southwest. Or you can resort to quoting an angle measured clockwise from North (in degrees);

Recall there are 360 degrees in a circle. So North would be 0 degrees. East would be 90 degrees. South 180 degrees. West 270 degrees. The advantage of quoting in degrees is speed and accuracy. This is related to bearings.