This article is our ultimate guide on how to use a compass.
Do you know how to use a compass in the field?
Trust me. You should.
For many newbie adventurers, the age-old art of map-and-compass navigation is extinct. After all, with the GPS offering detailed navigational information without the need for thorough knowledge, who needs a compass?
But is it really so?
Using a map and a compass delivers a more organic experience. They are a pair of reliable tools you can use anywhere without the risk of running out of power.
There’s no denying the ease of use and functionality of a modern GPS. But even so, every outdoor lover should be well-versed with the hands-on technique of compass reading.
Now, that’s not to say learning to use a compass is easy. In fact, you may find some steps listed below to be somewhat difficult to grasp for the first time.
That’s why we’ve included the best video we found on each topic. They are inserted right after the written instructions on any particular topic.
Let’s get started.
How Can You Use The Compass?
The primary purpose of the compass is to point you in the right direction. Once you align the compass with a topographical map, you can match your location with the surroundings. This way, you can head in the right direction.
This involves the following steps:
- Fixing your exact position in the wild from the compass and map.
- Fixing a direction or bearing from the map and moving towards it.
- Matching the features between the map and the ground as you move along.
- Identifying your location with respect to known objects at a distance.
Before we get into the details, let us look at a fundamental question. What is a compass bearing?
Basically, the compass face has four cardinal directions, north, south, east, and west. This circle is divided into 360 degrees.
The compass bearing is the direction given by the compass towards an object in terms of angles. It always indicates the straight-line direction from one point to the other.
In theory, there are 16 standard bearings in a compass. Each of them is 22.5 degrees apart from the other There can be other non-standard bearings as well.
You can take the bearing N25W as an example. The standard practice is to start at north or south and then rotate by the given angle towards east or west.
The Anatomy of a Compass
The magnetic compass is one of the oldest navigational tools. By principle, any magnet allowed to rotate freely will align itself with the earth’s magnetic field. In a compass, a lightweight magnet forms the needle, which pivots around a frictionless point.
The basic field compass is also called the baseplate compass. This is so because it’s mounted on a base plate with markings. The following are the main parts of this compass.
- The base plate or the clear flat plat over which the compass is mounted
- The edge of the baseplate can have scales and numbers marked on it. This can allow users to place it on the map and calculate the distance between two points.
- The travel arrow is an arrow that points forward. It is always pointed towards the direction you are moving.
- The degree dial is a circular bezel on the compass housing that is rotated around the compass. The 360 degrees of the circle are marked on it.
- An index line or pointer on the top of the bezel which helps to read the bearing.
- The magnetic needle is the needle spinning in the center. The red end of the needle always points towards the magnetic north, which is… not the true north.
- The orienting arrow is another non-magnetic arrow inside the dial. You can align this arrow with the compass needle to help maintain the right direction while moving.
- Orienting lines are the parallel lines on the compass face that rotate with the bezel.
Adjusting for Declination
If you think that the compass needle always points towards the North, think again.
Actually, that isn’t so simple.
The fact is, there’s a big difference between the true geographic north and magnetic north.
The true North Pole is the point where all the longitude lines meet and it’s in the middle of the Arctic ocean. Likewise, the true South Pole is located in Antarctica at the exact opposite end of the earth.
However, the northern magnetic lines of attraction converge on the North Ellesmere Island in Canada. The magnetic needle of the compass will always point to the magnetic north.
Due to the fluid molten core of the earth, the magnetic north keeps on shifting position. While the present difference between the two poles is around 500 kilometers, it changes every year.
The difference between the magnetic and the true north is termed declination. This value will be different at different locations on the planet.
In other words, if you draw two lines from your current position to these two different poles, declination is the angular difference between them. So if you don’t adjust your compass to account for declination, you will be heading in the wrong direction.
While it may not be significant for small distances, it can have a major impact when it comes to long cross-country hikes.
The good news is, all the latest maps come with declination diagrams for your area to help you out. Each map also comes with a date. So it’s best to use the latest maps for the most updated diagrams.
You can also use the NOAA website to find out your declination. Once the declination is set for a trip, you don’t need to worry unless you move over to another distant location.
Hold tight here… We are about to get technical.
If you trace the line of zero declination in the United States, you’ll find it passing through Alabama, Illinois, and Wisconsin. This is where the North Pole and the magnetic pole are aligned with each other.
If you move to the east of that line, the magnetic north shifts to the west of true north. The reverse is true if you move to the west.
Keep in mind, each time you take a bearing in the field, you need to add or subtract the declination to get the true bearing. In case of a negative declination, the compass needle will point west of the north mark. For positive declinations, it will point to the east of the north mark.
I know what you’re thinking. When to add or subtract the declination value?
For a west declination, you need to add to the original degree reading. In case your area has an east declination, you’ll have to subtract that from the original reading.
Also, while transferring a magnetic bearing from the field to the map, add the magnetic declination. While transferring a bearing from a map to the field, subtract the declination value.
We know that was a lot, and it can be challenging to follow for the first time. So below is an excellent video demonstration:
Note, some compasses from the top brands like Brunton and Suunto have adjustment keys for declination adjustments. Here, the declination correction can be fixed or adjustable.
The process of fixed declination correction uses an additional scale under the compass. The declination is to be adjusted each time a compass reading is taken.
In the case of adjustable declination correction, the declination is set once when you start navigation. Unless the declination value changes, no more adjustments are needed for the readings.
Navigating With a Compass – The Basics
Check the Direction You Are Facing
Before we go into the details, here’s the first basic exercise to do with a compass. This is to check the direction you are facing. Here are the steps that you need to follow for that.
- Hold the compass flat on your palm at chest height. The direction arrow should be pointed outwards.
- Unless you are facing north, the magnetic needle should be pointing at one side or the other. Now rotate the dial, until the orienting arrow matches with the magnetic needle.
- Next, check the position of the direction of the travel arrow. If it is between north and west, you are facing northwest.
- Check the degree at the point where the direction arrow intersects the dial. It will give the exact degree of the direction you are facing.
Note, you can use the same method in a different form to find out a particular direction in the outdoors. That’s a simple but vital purpose a compass can serve during an emergency.
Determine the Compass Bearing of a Distant Object
Next, we look at how to determine the compass bearing of a distant object. We have already explained what a compass bearing is. You can do it in three simple steps.
- Hold the compass at chest height with the base plate straight.
- Mark a distant object. Turn your body so that the direction arrow is pointing towards the object.
- Rotate the compass dial till the magnetic arrow matches with the N mark on the dial.
- Note the degrees at the index line. This is the required compass bearing.
It is best to navigate based on smaller objects like trees or telephone poles. Large and distant objects like mountains are not precise enough for accurate navigation. A video demonstration is included in the next section.
But that’s not all…
Orient Your Map
A compass can also help you in setting the map. That means you can orient the map with the surrounding landscape. When this is done, the north of the map matches the direction of the actual geographic north from your location.
Once the compass and the map are oriented, matching the features you see on the ground with the map gets easier.
To do that, place the map on a flat surface and put the compass above it. Align the compass base with the gridline. Then, turn the map and compass till the compass needle fits in the orienting arrow. Now, your map is oriented.
Again, we’ve found the most helpful video on this topic. Check it out below:
How to Use a Compass to Find Where You Are?
Before you start using your compass with a topo map, make sure that you know the basics of reading a map.
The main feature of these topographic maps is the contour lines that allow you to visualize the geography of the terrain. They can also come with key features of a trail that are highlighted to help you find directions more easily.
Now, the first step for figuring out your location with a map and compass is to locate two or three known landmarks that can be marked on the map. These can be mountain peaks, lakes, or any specific landmark. Now follow these steps.
- Orient your map in line with the compass so that the map north points towards the true north.
- To take a bearing for the first landmark, line up the direction of the travel arrow towards that landmark.
- Next, rotate the compass bezel until the compass needle matches with the orienting arrow.
- At this position, the index line will tell you the bearing.
- Now place the compass on the map with one straight edge aligned with the landmark and pointing at your trail.
- Next, rotate the bezel till the orienting lines are parallel with the north and south of the map. Also, the north marker of the bezel should align with the north of the map.
- At this position, you can draw a line between the landmark and your trail. The point at which the line crosses the trail is your position.
You can repeat the steps for the other two landmarks. Finally, the three lines will intersect and form a small triangle. This is the method of triangulation. Your location is somewhere in that triangle.
If the triangle is too large, there are chances that you have made an error. In such cases, you need to redo the entire process.
At times the lines can also meet in a single point to give your exact position. Ideally, the landmarks should be at least 60 degrees away from each other for the best results.
What about a digital compass?
When you are using a digital compass in a wristwatch, you need to check the manufacturer’s instructions related to aligning the compass with the map and using declination correction.
Some compass watches also come with a bearing memory function. The memorized direction to the destination is displayed in the 12 o’clock position of the watch face.
How to Take a Bearing From a Map With a Compass?
While taking a bearing from sight is simple, you can also use a topo map to take the bearings. Here are the steps that you need to take to trace a path from your location to a distant object.
- Mark the two points on the map and set up the compass frame between the two points. The direction of the travel arrow should point towards the destination.
- Rotate the compass bezel till the orienting lines are parallel to the grid lines of the map.
- Read the bearing at the index pointer. Then add or subtract the declination value and adjust the degrees accordingly.
- Congrats! Your bearing is ready.
How to Follow a Bearing With a Compass?
Once you have taken a bearing, the next step is to follow the bearing until you reach your destination. For that, note the following steps.
- Remove the compass from the map and hold it on your palm. The direction of travel arrow should be pointing ahead.
- Rotate your body and the compass till the red needle is aligned with the orienting arrow.
- At this point, the directions of the travel arrow should point towards the landmark you will be traveling towards. In other words, you are facing the exact degrees that are your bearing.
- Now you can walk in the direction towards which the direction of travel arrow points.
With these basic steps, you can use a compass to find a route around in most situations.
Using your Smartphone as a Compass
Since a smartphone contains a magnetometer, you can use an app that works as a digital compass. There are a wide variety of apps available in the stores that you can pick.
However, the accuracy of digital compasses can be affected by the presence of electromagnetic fields, electronic objects, and metallic objects. So make sure you calibrate the compass at regular intervals.
In the case of iOS, you can go to location services and turn on compass calibration under system services. On an Android device, you can move the phone in a figure of eight fashion a few times after launching the compass app.
Note, you don’t get the usual direction of travel arrows and orienteering lines with a smartphone compass. But an IOS compass can be combined with Apple Maps for navigation. In the case of Google maps, you can use the embedded compass in it to find your direction of travel.
But the thing is, you will be dependent on the limits of the smartphone battery for the compass to function. Also, in the wilderness, you can’t depend on cellular signals for finding directions.
Tips to Follow While Using a Compass
There are a few points you need to keep in mind while navigating by using a compass.
- While following a bearing towards distant objects, it’s best to divide the journey into small sections. You can also check your bearing at each interval to ensure that you stay on track. This is more important in wild terrains like forests or places with varying altitudes.
- Do not take a compass reading near ferrous objects. This can be your belt buckle or a survival machete hanging from your hip. Also, spreading the map and using the compass on a car hood can spoil your bearings. Other than that, power lines can also affect compass readings. It’s best to be aware of your surroundings before using a compass.
- Make sure to keep the compass level as best as possible when taking a bearing. This will improve the accuracy of the readings.
- The direction of your heading should always match with the direction of travel in the compass.
- Before you head out to the field, use the compass in your neighborhood to test your skills. Practice will make you perfect.
- Even if you are not carrying a map, using a compass to direct yourself towards the north can help you in a survival situation. This can also help you to reorient yourself after losing your bearings.
- Store a magnetic compass away from computers, cell phones, or pocket radios. Also, keep them away from hot objects.
Types of Compasses
Before buying a compass for your next adventure, you need to know the type that will serve you best. Here’s a look at the various types of compasses.
This is the most common form of compass used by outdoor lovers and was developed in the 1930s. We have already discussed the various parts of this compass.
Since the compass casing is mounted on a protractor base, transferring bearings from the compass to the map is easier.
A baseplate compass is also an affordable option. In some cases, it comes with luminous components for night use and a magnifying lens for map reading.
This compass makes use of multiple devices to function. They usually include a magnetometer and tilt sensors. In addition, accelerometers and gyroscopes can also be used.
They are used in the navigation of unmanned aerial vehicles and deep-sea vessels and also in the positioning of geostationary satellites. However, they require a power source to run.
Keep in mind, an electronic compass is not the same as a GPS unit. A GPS unit is dependent on satellite signals and needs movement to determine your direction. Combining a GPS with an electronic compass will demand a higher price and also drain the battery life faster.
On the other hand, digital compasses used in wristwatches have a direction sensor that detects the subtle changes in the earth’s magnetic field.
A microprocessor converts these changes into the compass display of the watch. Some of these watches also come with features like declination correction and bearing indicator.
This is a compact version of the baseplate compass where the baseplate is redesigned to fit the thumb.
These compasses are mainly used by competitors participating in adventure sports contests. The advantage is, you can use the compass and the map with the same hand while continuing to run.
With a thumb compass, you don’t need to stop and place the compass on the map either. Thus you can move faster and change directions quicker.
The card compass is used in marine vessels and boats. Since they are usually mounted near the steering, they are also called steering compasses.
Here, the compass needle is fixed and the compass card is placed on a fluid. The readings between 0 to 360 degrees are marked on the card.
The card is mounted on a fluid and it absorbs the rolling and pitching motions of a ship more effectively. That makes taking readings easier.
Basically, the gyrocompass is a type of gyroscope with an electrically powered gyroscope wheel and a non-magnetic compass.
It is used in most merchant ships or naval vessels as it can point towards the true north with high accuracy. Moreover, it remains unaffected by external magnetic fields- a drawback that most magnetic compasses suffer from.
The gyroscope can freely rotate along any of the three mutually perpendicular axes and uses the rotation and gravity of the earth to point towards the true north.
Most ships use data from a GPS receiver to feed the gyrocompass. This results in eliminating any errors due to the ship’s movement or latitude.
Fact is, learning how to use a compass is a necessary skill for all outdoor lovers who frequently travel in remote areas. Compared to other camping essentials, a compass doesn’t take up much space. Is lightweight and consumes no power. Frankly, they are almost indestructible.
Most importantly, a compass can be a lifesaver in case of an emergency.
We have shared the basics of compass-based navigation with you. The secret to perfect compass navigation is practicing and developing your skills.
It’s all in your pitch.