If you want to learn how to use a compass, then you need to know how a compass works and learn to trust your readings. I have taken orienteering classes in the past and researched for 2 days to learn some more information to help you learn how to use a compass.
This article will cover the parts of a compass, maps, declination, how to navigate obstacles, how to find yourself with a compass, and more!
Baseplate: These compasses are clear so you can see the map underneath your compass. These compasses are also useful for aligning your orienting lines which I will cover soon.
Travel arrow: This arrow will be your guide. It will show you which direction to go when finding a bearing. You can also call this arrow D.O.G. Direction of go.
Rotating bezel/Azimuth ring: The circle of the compass dial with numbers and little lines. The azimuth can rotate up to 360 degrees.
Cardinal directions: North is tricky, it is 0° and 360° degrees. East is 90°, South is 180°, and West is 270°. If you know these degrees then you are less likely to make mistakes when navigating
Index line: Usually says Read bearing here with a straight dark line.
Fixed Bold line: Below it you can usually see a bold line, which aligns with the index line. This is where you put the smaller lines into.
Dial lines: Each small line represents two degrees. Count evenly, 2,4,6…
Declination marks: Red marks on the inside of the bezel, designed to help adjust for declination.
Magnetized needle: Always points to magnetic north, and is either a red or white-tipped needle.
Orienting arrow: Helps orient the bezel, and has a precise red outline that fits the end of the magnetized needle.
Orienting lines: Vertical lines that move with the bezel, align them with the north-south lines on your map. This aligns your orienting arrow with north on the map.
True north always points to the north pole, but magnetic north (where the red arrow points) differs from true north. The difference in degrees between true north and magnetic north is known as the declination.
A degree or two off from declination can bring you miles away from your destination. To travel safely it’s important to know how to factor in declination.
To further complicate matters, declination changes over time. If you look in the legend of your map you will see something like this.
Mapbuilder Topo Openstreetmapcontributors (what declination looks like)
Always make sure your map is up to date. A great way to find your declination is by using this site. https://www.magnetic-declination.com/
The way you adjust for declination varies depending on your compass. Most have a small tool to set it up, but some don’t, follow the instructions for your compass. Once the declination is set, you won’t have to worry about it unless you travel farther away.
You can account for declination by calculating it in your head. When do you add, and when do you subtract declination? Answer…Always subtract a positive declination and add a negative one.
Another key to remember is West is best, and East is least. Add to the West which is a larger number. Subtract from East which is a smaller number. This makes more sense if you look at this chart.
I do not recommend using a compass without a declination adjustment. I would recommend investing in a compass that accounts for declination because a compass can theoretically last for life.
Also if you find yourself in an emergency scenario, you want to be thinking about as little as possible. Many people panic and behave irrationally in intense situations. Declination is just one more factor you will have to think about in this context.
Orienting a map
Mapbuilder Topo Openstreetmapcontributors
How do you orient a map? It’s quite simple actually. Place it so the arrow that says N (true north) faces up. Now to involve the compass. Don’t worry, orienting a map with a compass is a lot easier than declination which trips most people up.
Simply place your compass on your map with the travel arrow pointing towards the top of the map.
Rotate your bezel until N is aligned with your travel arrow.
Slide your compass until the edge of it is aligned with either the right or left edge of your map.
Last step. While holding both map and compass, carefully rotate your body until the magnetic needle (red-tipped) is inside the red outlined arrow. Think of it this way, red in the shed. The shed is a red outlined arrow called the orienteering arrow.
Pro tip: Make sure North is on Top! Important information if you are heading in the opposite direction from where you came. Remember that the top of your map always points north.
Remember this because it’s easy to line up your orienteering lines while south is at the top because it’s quicker. But you have to turn the bezel 180 degrees, here’s why.
With South at the top of your compass instead of North, you would actually be going in a complete 180 from your intended direction.
Turn the bezel all the way around until north is on top, then align your orienteering lines. It’s very easy to mistakenly leave South at the top when you’re going in the other direction.
Finding a bearing
Put your compass on the map so the edge of it lines up between your current location and your intended destination.
The travel arrow should be pointing towards your destination, not towards you. (Make sure it’s not upside down)
Look at your map. Do you see small lines forming squares? These are the north-south grid lines I mentioned before. Your orienting lines should be aligned with these grid lines.
Be careful when aligning these lines, and double-check to make sure they are aligned well. If not you can end up more than a mile away from your destination.
Read the index line which has the bearing to your destination
Hold the compass close to you if you have no metal which will interfere with the magnetic needle. Hold it away if you have something metal on you.
Rotate your body until red is in the shed. Now the travel arrow is facing your captured bearing, follow this arrow to reach your destination.
Dead reckoning: Do not keep your eyes glued to the compass, Instead find a bearing, and double-check which tree or rock you are walking towards. Now put away your compass and walk towards that bearing, repeat this process until you reach camp.
Taking a bearing
Mapbuilder Topo Openstreetmapcontributors
Finding a bearing and taking a bearing differ. Taking a bearing means you record an object’s location. This helps you find your current position.
Finding a bearing means you keep red in the shed and keep it pointing to the right degree until you reach camp. Simply put, finding a bearing helps you find your destination.
Find a landmark that is identifiable on a map, like a lake or peak. Hold your compass flat, with the travel arrow pointing at the landmark
Rotate the bezel until the magnetized needle is housed within the orienting arrow. Red in the shed.
Read the index line to capture your bearing.
Align one corner of the compass with the landmark on your map.
Align the orienting lines. After that, have north point up like the north on your map.
Now draw a line along the edge of your compass. Pay attention to where the line you draw crosses the trail that you are on.
Pro tip: If you are afraid of getting lost, have a backup plan. Use emergency satellite beacons like spot messenger or get download maps on your phone. Then use the GPS to locate yourself on a map (even without reception).
Mapbuilder Topo Openstreetmapcontributors
You can also find your location through triangulation.
Pick a second and a third landmark that are at least 60 degrees from your 1st landmark, and each other.
The lines you draw from those marks should meet at a single point and make a triangle. If your triangle is big, try making it smaller by correcting your measurements.
Pro tips: Compasses can be damaged by reversed polarity if they are stored near electronics.
What to do next?
Congratulations! You understand how a compass works, now you must trust your readings. Practice navigation in a familiar environment (house/trail).
Use your phone’s compass to double-check yourself as you learn. Just don’t rely on electronics as your fail-safe.
Now that you know a little bit about compasses consider joining a navigation class, they are cheap to join.
You can also join an orienteering group. Navigation can be satisfying once you get the hang of it and it’s a great survival skill that can save your life. Compasses are one of the ten essentials, so don’t forget to bring it!