A compass is such a simple, yet effective device. It is one of those revolutionary inventions that has changed or accelerated the course of our history. Everyone knows what it is, but do you know how to use a compass? Truth be told, we live in a modern era and we don’t need a compass to navigate in normal circumstances. We have GPS, Google Maps, satellites, and other wonders of the modern world. Nevertheless, more than 2,000 people get lost in the woods each year. If it happens to you, your smartphone should be enough to call for help and read your favorite survival book while waiting for a rescue. Unless your battery runs out and leaves you on your own. In this scenario, you would be very happy about packing this ancient, but precise device. Not to mention any kind of disaster event accompanied by a power outage.
The compass was invented around 2,000 years ago in China. For centuries, it was mainly used for divination ceremonies and fortune-telling. However, between the 9th and 11th century it became a common navigating tool, spreading from China to Europe and the Islamic world. While it changed its purpose, the basic principle of working remained the same.
This miraculous device is basically a magnetic metal needle. If it can spin freely it will respond to Earth’s magnetic field. As a result, one end will always point to the north magnetic pole, while the other end will point to the south magnetic pole. It was so 2,000 thousand years ago, and it is so today.
Parts of a Compass
While the principle behind a compass is as simple as it gets, you need to know all basic parts of your compass to read it correctly. So, here they are:
Baseplate. It’s usually a plastic flat base on which the rest of the compass lies. It has straight edges to provide an easier alignment with a map. There’s also an arrow in the middle of the baseplate – direction-of-travel arrow.
Direction of travel arrow. When you use your compass properly it always points the way you will travel.
Index pointer. This is the rear part of the direction-of-travel arrow that points to the dial. This is where you take degree readings.
Magnetic Needle. It always points to the north. Most commonly, the part of the needle that shows north is red, while the other part can be black, white, metallic, or else.
Housing. Usually, it is a plastic container. Inside of it, there’s a magnetic needle, orienting arrow, and orienting lines.
Bezel or dial. The dial is a rotating ring around the housing. It has 360-degree markings as well as N, E, S, W letters.
Orienting arrow. It is drawn on the floor of the housing. It rotates with the dial.
Orienting lines. These lines are parallel to the orienting arrow. Their function is to simply provide a better view of the direction.
How to Use a Compass – Step by Step
A compass can show you which way to go or to establish where the cardinal directions are (or anything in between the cardinal directions). Cardinal directions are north, east, south, and west. I’ll use examples to make it more clear and understandable.
Let’s say you lost your track in the woods. However, you know that there’s a vast wilderness to the northwest, and civilization and the nearest road is somewhere to the southeast. Before you even start make sure that there are no metal objects in very close to the compass. Metal objects such as a gun, knife or even key chains can cause false readings.
Step 1 – So, you want to determine where the southeast is. First, find out SE marking on the compass dial. Now, turn the dial so that SE comes exactly where the index pointer and direction-of-travel line meet the dial.
Step 2 – Hold your compass steadily and flat in your palm. The direction-of-travel arrow should point straight away from you. Turn around slowly. Make sure that you don’t rotate the compass. As you spin the magnetic needle will move. Keep spinning yourself until the north (red) end of the magnetic needle is perfectly aligned with the orienting arrow and north (N) mark on the dial.
Step 3 – That’s it! You can start walking. Just follow the direction of the direction-of-travel arrow, and you’ll be heading southeast. However, be careful not to make some common mistakes. Make sure that you’re aligning the red end of the needle or you might head in the opposite direction. Also, the magnetic needle tells you where the north is and not where you want to go. That’s what the direction-of-travel arrow is for.
You are heading to the mountains and you want to determine your direction.
Step 1 – Face the mountain top you want to reach. Hold your compass in your palm so that the direction-of-travel arrow points to the designated mountain top.
Step 2 – Turn the bezel to align the magnetic needle, north (N) mark, and orienting arrow. Now, take a look at the place where the bottom of the direction-of-travel arrow (index pointer) meets the dial and read your bearings. The number or mark indicates your direction.
How to Use a Compass with a Map
Previous examples show the basic way compasses work. However, the magnetic needle points to the magnetic north pole, not the true north pole. So, it might be precise, but usually, it is not. To determine the accurate direction you need to execute one more step – account for declination. It is the angle between magnetic north and true north. I didn’t mention it earlier because it is connected with the use of maps. You should have a modern map because magnetic poles wander over time, so the declination changes.
Step 1 – Put your map on a flat surface. You need to travel from point A to point B. You know exactly where your starting point is. Use the side of your compass to line up points A and B. The direction-of-travel arrow should point towards point B. Turn the dial so that the north (N) mark points north on the map. The place where the index pointer and dial meet shows your heading. Almost.
Step 2 – Now, it’s time to add or subtract declination. Your map should show the declination of your location or you can calculate it online on the NOAA website. Add a negative declination and subtract the positive one on your dial.
Step 3 – Now you know your bearing, so you just have to determine which way to go. Repeat Step 2 from Example 1 and the direction-of-travel arrow will show you the way.
A compass is one of those cool things that you hope you’ll never have to use except for fun. But in case of disaster, you’ll be thankful. With the ability to navigate you’ll feel more confident and more relaxed. It is helpful to keep your head clear and avoid mistakes such as hasty decisions or normalcy bias. A compass, weapons, IFAK, space blanket and the rest of your gear are helpful, sometimes even necessary if you get lost. But, making the right calls is the most important thing to keep you safe.