Carrying a compass on a hiking trip is already a good start. Knowing how to use it and find your bearings is even better! A compass is a simple tool that works in all conditions and, used alongside a map, will get you out of most navigation problems. Here are some basic tips for using a compass effectively when hiking or trekking, as a complement to the other navigation advice already published on this site.
Compass guide
A compass has at least 3 components:
– A mobile magnetic needle, whose red tip points to Magnetic North.
– A direction-of-travel arrow, a fixed arrow on the compass baseplate that you point towards the direction you want to follow or towards a landmark; the direction-of-travel arrow can also be the edge of the compass baseplate ruler.
– A graduated rotating bezel.
It is worth noting that the needle indicates Magnetic North. There is a difference between Magnetic North and True North: this is called magnetic declination (magnetic declination is indicated on IGN maps). At our latitudes, it is relatively small and can be disregarded over walking distances. In regions closer to the poles, it is essential to correct your bearing for magnetic declination and to use a compass specifically designed for that purpose.
Compasses can also be fitted with a mirror sighting bezel, making them easier to use and allowing for more precise sighting.
A compass is sensitive to magnetic fields: do not use it too close to a phone battery, and certainly not under power lines!
A compass will allow you a few basic uses: locating yourself on a map and following a bearing to reach your destination.
Using a compass to orient your map
Orienting your map is essential before any other use of the compass, and also before reading the map. Every time you take stock of your position, this is the first step to carry out. Of course, you can orient your map using a few landmarks or your own sense of direction, but using a compass will be more precise and free from errors of judgement.
Place the compass on the map and position it so that the direction-of-travel arrow points towards the north of the map and is parallel to the north-south axis of the topographic map. Depending on the map brand, north may be indicated differently, but generally it is the top of the map or the grid lines.
Once the compass is correctly placed, rotate the whole "map + compass" unit in the horizontal plane until the magnetic needle aligns with the direction-of-travel arrow. At that point, your map is correctly oriented towards North. Any direction on the map corresponds to a direction on the ground.
Using a compass to locate yourself on the map
Imagine you are on a path marked on the map but you don't know exactly where you are on that path.
First, orient your map to North as described above. Then identify a prominent high point in the landscape that you can clearly recognise on the map: a church steeple, a distinctive summit, a radio transmitter mast, a peak, a water tower… and so on.
Without moving the map, but only by moving the compass, point the direction-of-travel arrow or the right edge of the baseplate towards the identified landmark on the map while sighting it in the field. The line thus drawn will cross your path at the point where you are standing.
You can repeat the process for greater accuracy, or carry out a triangulation (sighting 3 distinct landmarks) to pinpoint the zone you are in with reasonable precision.
Using a compass to follow a bearing
Imagine the following situation: you know where you are (point A) and you want to reach a hamlet you can see in the distance (point B), but you know that as the terrain folds you will lose sight of it.
– First, point the direction-of-travel arrow of the compass towards your target — point B on the map or in the field: the compass is then aligned along the straight line connecting point A to point B.
– Rotate the rotating bezel until the North mark on the bezel coincides with the North indicated by the magnetic needle.
– Read the azimuth (bearing to follow): this is the value displayed in the direction of the magnetic needle.
Keeping your compass horizontal and with the north of the magnetic needle always aligned with the north of the graduation, you can walk in the right direction by following the indicated bearing. Make corrections whenever point B reappears in view, and adjust your direction if you need to go around an obstacle or make a lateral move.
Using a compass isn't complicated, but it does take a little practice. Don't hesitate to practise on familiar terrain or to run small navigation exercises on a hiking route you know well. This will build your confidence for the moments when you find yourself on unknown ground and need to rely on a compass. Carrying a compass on a hiking or trekking trip is essential — and so is knowing how to use it! You now know the basics, and we'll be back soon with a new article covering more advanced techniques.
