Learn old school methods for using a traditional map and hand-held compass
Handheld GPS devices and GPS-equipped smartphones are invaluable navigation tools for outdoor enthusiasts, however, they shouldn’t be relied on when your life is at stake. Plastic cracks, glass screens shatter, circuit boards fry, batteries lose their charge.
That’s why anytime you’re heading off-the-grid to find solitude, a paper map and magnetic compass are absolute non-negotiables. But simply carrying these analog navigation necessities isn’t enough — you must also possess the skills and knowledge to figure out where you are, where you need to be, and how to find your way safely.
And it all starts by learning your way around what many might assume is an outdated technology: the humble paper map.
Getting the Right Map for Your Journey
Many varieties of hard-copy maps are produced, but the kind most applicable to hikers are called “topographic maps,” or “topo maps” for short. The most popular and reliable topographic maps are produced by the United States Geological Survey (USGS) and are available for practically every area of the United States, covering all the National Parks, National Forests, BLM lands, and anywhere else you might want to hike.
There are several great online resources for finding and printing official USGS maps or similar topographic maps for any area you’d like to hike. To start your search, check out caltopo.com or alltrails.com.
Understanding Topo Map Contour Lines
What makes topographic maps so helpful for hikers, mountaineers, or anyone navigating through varied terrain, is the addition of contour lines. By connecting all points on the map sharing common elevations, contour lines create a visual representation of real landscape features — peaks, valleys, lakes, etc. — on a flat piece of paper.
As you’ll see when we look at how to take bearings, using contour lines to identify landmarks is vitally important when pinpointing your exact location on the map, and is an essential component to successful navigation.
Other important things to know about contour lines:
- If you look closely, you’ll notice that every fifth contour line is thicker than the others — these are called index lines and each one is labeled with its corresponding elevation.
- A map’s contour interval is the amount of elevation change between individual contour lines. Most topographical maps (particularly the well-loved USGS 7.5-minute maps) have a standard contour interval of 40 feet which provides an adequate level of detail to identify prominent landscape features and make well-informed navigation decisions.
- Contour lines that are close together indicate a quick change in elevation implying a steep slope, whereas lines that are spread out suggest a more gradual incline. Contour lines that form rings represent peaks or hills, and those that form “V” shapes reveal the locations of valleys, gullies, or other drainage-type features.
Reading the Map Legend
A map’s legend defines all the colors, lines, and symbols used on the map. Since map legends are relatively self-explanatory, we won’t go into detail on them here. There are, however, two bits of information contained within a map’s legend that are often overlooked by casual map readers but are of extreme importance to backcountry navigators:
- Scale — A map’s scale describes the relative “real world” distance represented by the map. USGS 7.5-minute maps have a scale of 1:24,000, which means that one unit on the map is equal to 24,000 units on the real landscape. The unit of measurement you use can be anything, but for convenience, most maps provide a small diagram that shows how many miles on the ground are represented by one inch on the map. This provides valuable insight in the field when calculating distances and estimating travel times.
- Magnetic declination — USGS topo maps (and most maps in general) are printed so that true north — AKA the North Pole — is at the top of the page. But there’s a problem: your magnetic compass points to magnetic north which is actually on Ellesmere Island in Canada, roughly 310 miles from the North Pole. However, by calculating magnetic declination, which is the difference in degrees between true north and magnetic north from your current location on the globe (very important), you can adjust your compass to compensate for the difference, allowing you to follow the magnetic needle on your compass as if it were pointing to true north. Thankfully, most reputable topo maps have done all the hard math work for you, displaying the exact magnetic declination to use in a convenient diagram near the map’s legend.
And with that, it’s time to look at the tool that brings a topo map to life — the magnetic compass!
Meet Your New Backcountry Companion: The Compass
For serious navigation, you need a compass with a few important features that your run-of-the-mill compass might lack.
First, you must be able to adjust the declination of your compass. Most models with this functionality are known as “bezel compasses” and have a rotating ring on the face that’s used to take bearings, but can also be calibrated and locked in place with a set screw, according to the declination chart provided on the map.
Compasses lacking this feature can still be used for navigation, however, the magnetic declination must be compensated for manually each time you take a bearing — a very time-consuming process.
Compasses with clear base plates allow you to see the map through the compass, which helps you take more accurate bearings and plan better routes. At least one side of the base plate should have a straight edge for taking location bearings and tracing lines on the map when triangulating your location.
Most compasses also feature rulers on the base plate to help calculate distances by referencing the map’s scale, and some even have small built-in magnifying glasses to inspect diminutive map details.
Other important components of a proper navigation compass:
- Orienting lines — Help you align the compass bezel with your map when taking a bearing.
- Orienting arrow — Located within the bezel, the orienting arrow perfectly outlines the magnetic arrow when orienting the map.
- Direction of travel arrow — Indicates which direction to aim the compass.
- Index line/marker — This small but important mark along the edge of the rotating bezel that indicates the degree of your bearing reading.
Essential Map and Compass Skills
The skills we’re about to cover could potentially save your life in an emergency or at least make a rough weekend in the woods suck a little less.
1. Orient Your Map
Okay. You have the appropriate USGS topo map for the area you’re exploring and you have the proper compass with its declination adjusted according to the diagram on the map. But before you can start taking bearings, it’s important that you take a second to orient your map with your surroundings.
- While standing up, hold your map open flat and position your compass on top of the map so that one of its straight edges matches up with the edge of the map.
- Make sure the direction of travel arrow is pointing straight ahead toward the top edge of the map then rotate the compass bezel until the North marking is pointing the same way.
- Keeping the map and compass in the same position, slowly turn on your feet until you see the magnetic needle line up with the orienting arrow.
2. Take a Location Bearing
With your map oriented, you should be facing true north and ready to cut tracks to your next destination — an alpine lake you want to check out, a new campsite, the nearest road, etc. But in order use your compass for guidance, you must first take the bearing of your destination, a process that involves a small learning curve at first, but becomes second nature with practice.
In simple terms, a bearing tells the direction of travel to reach a specific destination. A location bearing (AKA “map bearing”) is used when you can identify both your current location and your chosen destination on the map.
- With your map properly oriented, position your compass on the map with the straight side of the base plate touching both your current location and destination location. The direction of travel arrow should be pointing toward the destination — this is how you’ll be holding the compass while following the bearing.
- Keep the compass in position and rotate the bezel so that the orienting lines inside the bezel are running north/south, parallel with the edge of the map. Double check that the “N” on the bezel is pointing toward the top of the map.
- To “capture the bearing,” simply look at the index line to and read the degree marking next to it — that’s your bearing.
To follow that bearing to your destination, simply leave the bezel at the bearing mark, keep the direction of travel arrow pointing straight ahead, then spin your body until the magnetized needle is framed by the orienting needle. Time to start hiking!
3. Take a Bearing from Landscape Clues
Beyond basic point-to-point navigation, the real value of bearings comes to light when you need to figure out where you are on the map. This is done by taking a bearing from a real landscape feature — the more prominent the better.
- Choose a landscape feature — let’s say a snow-capped peak in the distance — you can easily see from your current location and find on the map.
- Point your compass toward the peak out in front of you with the direction of travel arrow straight ahead.
- While keeping the compass aimed toward to the peak, look at the face and rotate the bezel until the orienting arrow frames the magnetized needle.
- Capture your bearing by reading the degree number marked by the index line.
- To transfer this bearing to the map for interpretation, place the compass on the map with the front edge of the base plate touching the peak location on the map.
- Then, pivot the entire compass to bring the orienting lines into north/south alignment.
- Draw or trace a line along the edge of the compass, intersecting the peak location on the map — your position is somewhere along this line.
If you’re on a marked trail you can identify on your map, you can often pinpoint your location by finding where the line you drew intersects the trail.
4. Triangulate to Pinpoint Your Location
If you’re off-trail, however, additional bearings are needed to hone in on exactly where you are on the map. This is called Triangulation and is one of the most important skills to know when the chips are down and it’s up to you navigate to safety.
To triangulate your location, you simply repeat the process above for taking a bearing from a landscape feature and repeat it two more times with other features. The peaks, lakes, or whatever landmarks you choose to reference should be at least 60-degrees apart, but closer to 90-degrees is preferred for accuracy.
After capturing the bearings, transferring them to the map and drawing their corresponding lines, a small triangle will be have been formed by the intersecting lines. If your readings were correct, your location should be somewhere inside that triangle.
Know Where You Stand and Trek with Confidence
If you take these old school navigation skills to heart, you’ll head out on your next wilderness adventure knowing that if you do get turned around, a little time with the map and compass is your ticket home.
But don’t reach for your compass only when emergency strikes — if you take bearings frequently and plot your course carefully as you go, you’ll know where you stand on the map at any given time so “totally lost” is never an option.