Being able to confidently use a compass and a map is one of the best ways to guarantee that you’ll never get lost in the outdoors nor fail to find a pirate’s buried treasure. If you’ve been wanting to gain this helpful and important adventurer’s skill, read on. You’ll learn the different parts of a compass as well as how to get to destinations on a map. When you unearth that mysterious crinkled map in your grandmother’s attic promising riches untold, you’ll want to be ready to grab your gear and go.
Parts of the Compass
The very first part of learning to read a compass is to learn the many parts that make up this tiny contraption. Each one serves a unique and important function. Let’s jump in!
The base plate is the (usually clear) plastic piece that lays flat. At least one side of it will have a flat edge and a ruler to help you measure.
Direction of Travel Arrow
This is the large arrow painted onto one end of the baseplate. Later, it will point in the direction that you want to go.
The compass housing is the circular part of the compass with the following pieces found inside of it:
- Compass Needle – The needle that floats and spins when the compass moves. The red end always points to Magnetic North.
- Rotating Bezel – The circle with numbers 0-360 all around the edges representing degrees. You can spin it so that the numbers line up in different areas.
- Orienting Arrow – This is an arrow painted onto the plastic that moves when you rotate the bezel.
- Orienting Lines – These lines are also painted onto the glass inside under the compass needle and rotate when the bezel does.
- Index Line – This is a line or dot just above the rotating bezel. When you have finished rotating the bezel to find your direction, the number lined up with the index line tells you your direction of travel.
What is declination? It is the difference between Magnetic North and True North, represented in degrees – east or west.
What’s difference between True and Magnetic North? Everyone knows a compass arrow points north, right? Surprisingly, that’s not quite true. Compass arrows point towards Magnetic North, which is the Earth’s magnetic pole. It’s a point somewhere in northern Canada that actually moves about 35 miles per year. That means that the angle the arrow points towards in California will be very different from where it points towards in New York, and it was very different in 1960 than what it is today.
To account for this, check the declination diagram at the bottom of your map. There will be a number in degrees. If your map doesn’t have this or it’s a fairly old map, look up the correct number online.
Once you have the number, turn your compass over and, using the little “key” tool that came with it, turn the tiny knob that rotates the orienting arrow (remember, the one that spins along with the bezel?) until it points to the number corresponding to your declination degrees. Remember: keep in mind east vs. west while doing this! In addition, be sure to change the declination if you take a hiking or seafaring vacation far from home.
Then, flip the compass back over, hold it flat on your hand, and turn your body until the red compass needle is lined up inside of the orienting arrow. Once those parts are laid out in the right way, wherever the north marker is pointing will be True North.
Take a Bearing from a Map
A bearing refers to the direction something is in, in relation to you. For example, if you want to accurately describe where the mountain you’re going to hike to is from your campsite or where the treasure chest is from the tallest palm tree, you might say, “Its bearing is 36° east.” Let’s learn about how to look at a map and figure out how to find an object in the field.
To start with, you need to know where you are already, so find your location on the map. Set your compass on top of the map on a flat surface (like a smooth rock or the ground) so that the straight part of the base plate lines up with your position.
Next, find the object or location you want to go to on the map and rotate the entire compass so that the edge of the compass touches both your position and the destination. Now turn the bezel until the orienting lines are lined up with North and South on the map (make sure North is pointing North and South is South!). You can now look at the index line and see what number is lined up next to it. That number is your bearing!
To put it into use, pick up your compass and hold it flat with the direction of travel arrow pointing out from your body. Spin your body slowly until “Red Fred is in the Shed”, or the magnetized needle is inside of the orienting arrow. Now, wherever you are facing is the direction of your destination. Good job! If you start walking in that direction, you should stumble upon the waterfall or doubloons within no time!
Compasses in a Nutshell
Did you love learning how to use a compass to find a destination on a map? Good, because there are lots of other ways to use a compass as well! With a slightly different set of skills, you can figure out where you are, based on landmarks, or you can pick a peak in the distance and figure out which one on the map it is, and more! Again, you will never be able to get lost – never!
Whether your plan now is to organize a backpacking trip or hire a scurvy crew of buccaneers for your quest, you’ll be ready to use a compass to get you pointed in the right direction.
See our Intro To Map Reading Page to learn more about maps.