Wilderness Compass Navigation Primer

2018 UPDATE: Since this article was first written, many things have changed for reasons of simple improvement or ease of use. In fact, this material has matured greatly since the time of this writing and there have been dozens of refinements. Take my Wilderness Navigation Course if you want to get more detailed information (compasses also available for sale on the course page). For now, two of the more important changes are as follows:

  • Book time is measured using 3 minutes per 100 feet of gain, plus 3 minutes per tenth of a mile. This makes the math a lot easier.
  • I stopped recording a back-bearing in parentheses. Instead now relying on the sheer simplicity of using “black to get to back.”

Now, here is the original article:

Two of the best ways to ensure you don’t get lost in the woods is to always know where you are and where you’re headed. If you know those two things you’re not lost. It doesn’t even matter what basic tools you use to know these two bits of information. Knowing is knowing. You might be a GPS user, and that’s okay, or you might use a map and compass only, and that’s fine as well. Since the common argument is that a GPS might malfunction or run out of power, HikeSafe recommends using a Map and Compass combination as one of the ten essentials — items you shouldn’t be without in the mountains.

I always bring my map and compass, and you probably always bring yours, too. But do you know how to use them (and I don’t mean to stand there and locate your cardinal points)? If you don’t, fortunately it’s not difficult to learn to use them effectively. And hopefully I can teach you how. In this article I will explain how to use these tools to navigate a simple bushwhack starting from the south end of Mt Osceola Trail, across Tripoli Road at the height of land in Thornton Gap, and through the woods to a identifiable point on the Mt Tecumseh Trail, so as to shave off a bit more than a half mile and 400-feet of unnecessary elevation change from the on-road/trail route. This would be used if hiking a hit-and-run from the Greeley Ponds trailhead to the Waterville Valley Ski Area parking lot so as to bag East Osceola Mountain, Mt Osceola, and Mt. Tecumseh in one hike. I will also add some tips and tricks at the end of the article you can use to refine and perfect this know-how. But first let me introduce the tools you’ll use:

Tools of the Trade

Anatomy of a Compass

Anatomy of a CompassThe image to the right offers a visual breakdown of the major parts of a compass but I’ll offer a little more explanation of these parts herein (the actual how-to will be discussed later in the article). I’ll start with the Direction of Travel Arrow and Direction of Travel Lines. These are parallel to the edges of the compass, which can also be used, and are indeed the direction you are to travel, in the field as well as on paper. The Bearing Indicator points the same way, but is used to mark a direction (number) on the 360º bezel. Next are the Orienting Lines (inside the face). These align to the true north-south longitudinal lines on the map with the red lines pointing north. Also inside the face is the Orienting Arrow, also known as “The Shed” and this is essential for knowing which direction to turn your body when following a bearing, but more on that in a bit. Next is the Magnetic Needle. The red end will always point to magnetic north. The last part requiring an explanation are the three USGS Scales shown on the edges. These may correspond to the scale of your map facilitating easy distance measuring. Now it’s time to take a look at the map.

Anatomy of a Map

Anatomy of a MapThe image inset is a typical topographic map such as what you’ll find included with the AMC‘s White Mountain Guide. (The map used in this actual example, however, was published by Map Adventures. I used it because it is in better condition than my AMC maps.) As with all topographical maps, the following features are present: First the blue lines. These are the Lines of Longitude (north/south) and Lines of Latitude (east/west). For our purposes, for small scale navigation, only the vertical longitudinal lines are important. Next we have Contour Lines. These are the curvy brown lines and on this map, each is representative of 100-feet of elevation. If you study them you might be able to pick out summits, notches, and other terrain features. It might take a little effort to “see” this, but just keep trying. The darker/bolder contour lines are called Index Lines and represent a specific interval. On this map each of those is 500-feet. If you study those index lines you’ll notice they’re occasionally marked with an Elevation Number. Speaking of elevation numbers, you can also find Summit Elevations on the map (sometimes other points are marked as well, like AMC Huts). Next is the Compass Rose/Legend offering information such as the contour line intervals, scale (to measure distance), etc. Also marked, and of great importance, is the Map Declination. This is the difference between true north and magnetic north. In this case, and at this date, since it is continually changing, it is rounded to 16º — being on the east coast, we would add this number to a true north bearing. It is for this reason flat maps are always printed in a true north configuration. This map has one other important marking, the Map Scale Bar, which is used for measuring distances (shown later in this article).

Now that the Tools of the Trade have been briefly explained, using a compass, a map, and a little pre-hike homework, let’s tackle that bushwhack.

A Working Example

Step 1: Prepping the Map

Area of Bushwhack - Click for larger area view

Click for a larger area view.

Make a copy of your map so you can write on it, and trim it to a size than can be stored, ready-to-use, in a sealed plastic bag. If following along (recommended) you will need to find the area shown in the Sandwich Range. The waterproof map I’m using for this article is only ten bucks and is, again, published by Map Adventures. Click on the thumbnail (see inset) for a larger area view, in full color. Note: Again, the contour lines on this map denote 100-foot elevation intervals with the bolder/darker, occasionally marked index lines at 500-foot intervals.

Step 2: Marking the Map

Area marked, route from right to left - Click for larger view

Click for a larger map view.

On the copy carefully mark at least two points on your map and draw a Course Line between them. The line will be straight for some if not all of the distance between them, it all depends on terrain. In this example I’ve marked where Mt Osceola connects with Tripoli Rd and drew a straight, single leg line, to a point on the Mt Tecumseh Tr located on the north side of the mountain. Doing this bypasses a significant portion of road walk and eliminates a good 400-feet of elevation difference. It should be noted that this line starts in Thornton Gap at the height of land and according to the contour line marks (the bolder line is 3000-feet, but its label is not visible in this photo), that is around 2800-feet of elevation. And this is helpful information with the right tools.

Step 3: Noting the Elevation

The course line in this example climbs west-southwesterly side slope (slabbing) 200-vertical-feet to the aforementioned 3000-foot contour line and generally stays there for a while. It then climbs another 200-feet before hitting slightly northwest of a dog-leg or trail bend in the Mt Tecumseh Tr end-point (intentionally, for reasons I’ll get to). This elevation data is important. Especially if you have an altimeter (do note if it calculates the altitude using the barometric pressure, be sure it’s calibrated before starting the bushwhack). You don’t need an altimeter to still find this info useful, though. Knowing the difference between up and down and being able to estimate four hundred feet of elevation gain over this distance can help you guess where you are. Be aware.

Step 4: Measure the Distance

Compare course length to this bar. Measure down to two-tenths (0.2 mi).

Compare course length to this bar. Measure down to two-tenths (0.2 mi).

And speaking of distance, this route is right around a half mile. This can be determined by the scale of the map, 1:750,000 in this case as shown in the map anatomy image (above), and the scale markings on the compass anatomy image (also above), if the map’s particular scale exists. In this case it doesn’t, the compass I used offers only 1:24,000 and 1:62,500 scales. To accurately measure the distance I must employ an alternative method: I can simply measure it using the map’s scale bar located somewhere on the map (see inset). I can use the ruler printed on the front of the compass to do this, or — and this is better for larger distances, I can mark a piece of paper with a pencil so as to transfer the course line’s actual distance to the map’s scale bar by moving the paper and physically holding it next to it. Dead simple.

Step 5: Getting a Bearing

Click for larger map view, in full color.

Click for larger map view, in full color (showing red lines). Lines of Longitude in image are gray, not blue.

With the course line drawn and the distance noted, it’s time to obtain a bearing. To do this put the compass on the Course Line aligning it exactly to the Direction of Travel Arrow, Direction of Travel Lines, or the left or right edges of the compass. Which indicator you use will depend on the where the Lines of Longitude are in relation to the Orienting Lines inside the face of the compass. You need to align those Orienting Lines to the Lines of Longitude, by turning the 360º Bezel, being sure the red end of those lines are pointed north on the map. Be as precise as possible. Once you have the compass perfectly aligned, the Direction of Travel Lines/Arrow aligned to the Course Line on the map, and the Orienting Lines aligned to the Lines of Longitude, it’s time to make note of the bearing. This is done by looking at the Bearing Indicator on the 360º Bezel and noting the number. The accuracy of this number is very important, especially when distances are greater. In this case, the bearing number I originally recorded was 252º (the image shows 251º because the photo was taken in a separate photo session and the course line was added afterward).

This is not the number we follow, though. Remember Map Declination? We have to add 16º to correct for this. In this example, starting with 252º adding 16 gives us a bearing of 268ºM, the “M” for Magnetic. Record this number, preferably on the map copy you made so all of the info is located in one place: bearings, distances, elevations, and any other thing you want to make note of such as landmarks not shown on the map but described in a written trail description, if one exists, and even an estimated travel time (see next image).

Step 6: Estimating Travel Time

Before you go racing into the field, bearing in hand, you should approximate and record your estimated travel time for the course leg. Knowing this value can help you navigate since you’ll know roughly when to start looking for your end-point. Any and all tools help, and time is one. The estimated travel time for the example half-mile bushwhack is 54 minutes. I arrived at that number by applying the AMC’s guidelines for book time (30 minutes per mile, plus 30 minutes per 1000-feet of elevation gain). A half mile is 15 minutes, and 400 feet of gain adds 12 more minutes for a subtotal of 27. Since it’s a bushwhack, multiply that number by two: 54 minutes. Bear in mind this number will vary based on group speed, snow type and depth, terrain, and/or vegetation type and density.

Step 7: Study the Terrain

Be sure to study the terrain as defined on the map and in any descriptions you can find. Will you cross water? In this example you won’t, but you will climb side hill 200 feet, flatten out for a bit, then climb 200 feet more. You will also encounter a gully right before hitting the trail. Also look beyond the trail and mountain it’s on. Look for surrounding peaks, some might be visible offering a reassuring frame of reference. The more information you have, the more likely you will succeed, provided you take your time and keep a clear head.

Step 8: Take Notes

Click for a larger map view.

Click for a larger map view.

Before you put the map away, be sure to jot it all down, right on the map as shown in the image (inset, right). The A-point or starting-point elevation and the B-point of end-point elevation. The distance, the estimated travel time, and of course the bearing, most notably the magnetic bearing, written right next to the course line. A direction arrow written right on the course line might also be useful if others will use your map.

Now you’re ready.

Taking it Outside

Step 1: The Starting Point

You’re finally outside. Finally! We probably all feel the same way about homework, but the preparation in this case really is worth it. It can mean the difference between shaving some distance off a hike or being hopelessly lost in the woods. At your starting point, the first point on your bearing line, verify your bezel is set to the proper bearing. As you may recall, in this case it is 268ºM (this will line up with your compass’s Direction of Travel Arrow). Once set, turn your entire body until the red end of the Magnetic Needle nests inside of the red Orienting Arrow, a.k.a. the Shed. As the expression goes: “Put Red in the Shed.”

Step 2: Staying on Course

With Red in the Shed, while holding the compass in front of you — the Direction of Travel Arrow pointing directly away from you — the direction you want to travel is straight ahead. But before you start walking, trying to navigate through the woods, staring at the compass while you bump into trees, pick a landmark directly ahead: A recognizable oddly twisted tree, or boulder, for example. Something you’re not likely to lose if you take your eyes off of it. The distance to this landmark depends on sight-lines, density, terrain, visibility, and in very low visibility or at night there are other things you can do, but I’ll get to that in the Tips and Tricks part. Check the time, verify your starting elevation, then walk towards your landmark — no need to look at the compass. Zig-zag all you want to make the walking easy, provided you end up at your landmark you’ll have done well. Rinse and repeat, align your body, pick a landmark, and start walking.

Step 3: That’s It!

That’s it. Pay attention to the time and elevation, look for the clues offered by the course due to terrain, elevation gain or loss, ridges versus valleys, and/or any features you might know about, such as a stream or meadow; or the aforementioned gully you will encounter before hitting the trail, in this case. Even knowing, based on elevation and locale, what kind of vegetation you’re likely to encounter can really help you (which is why I suspect the other obvious route in this bushwhack — following the ridge line to the second trail dog-leg — would be more difficult to travel). As you cover the expected distance in the expected time, starting looking intently for your destination. In this case it’s a trail and you’ll hit it on a slight angle, but almost perpendicularly to your course.

Tips and Tricks

Tip 1: Purposely Off-Setting Your Course

I could have made this course line head directly to the bend or dog-leg in the trail, but I didn’t. The course runs more northwesterly by maybe 1-degree, downhill of the dog-leg. Moreover, when one is side slabbing a grade, the tendency is to veer downhill slightly (just as one’s tendency is to walk with their back to the wind). I off-set the course intentionally, and factored in the power of gravity intentionally. I want to hike to a point downhill of the dog-leg. Not only will I be able to check the trail is leading in the right direction when I find it (as it does on the map), but walking up it I will quickly reach the dog-leg and thus solidly confirm my location — this is especially important if doing a multi-leg bushwhack. Heading above the dog-leg wouldn’t offer this advantage. Moreover, it would be a further distance with greater time requirement.

Tip 2: Create a Back-Track

When I boated in the ocean (for many years that was my thing) I would use a GPS with a mapped chart plotter overlay. While very easy to use and very accurate, I also logged my course on a navigational chart as I went. I did this in case my electronics ever went out I’d know precisely where I was and where I was headed. This was simple to implement because I could have everything laid out next to the helm on a chart table. In the woods things are different. In the woods I suggest using the map and compass as the primary tools, and the GPS as backup. Specifically I like using a GPS’s track feature which records my progress. If I ever need to backtrack and make a hasty exit — while I can have a back-bearing at the ready (the opposite course), having a specific line to follow might speed my progress. Additionally, if you’re just starting to practice with map and compass navigation, having a GPS can help you confirm distance traveled and can offer reassurance.

Tip 3: When to Practice

Speaking of practice, it’s probably best to do this at a time of year that offers better sight lines (due to limited foliage) and with snow cover so as to lessen impact. It’s especially important to avoid mud season as it’ll be easier to create a herd path and that should be avoided. Hiking a bushwhack is fun and rewarding when done right, but creating a new trail in untramped woods is a no-no. Leave no trace.

Tip 4: Other Traveling Methods

Besides using a landmark to walk toward, if the woods are really dense you can send a person ahead and visually adjust their position verbally, then walk toward them as they wait. Repeat as needed. Perhaps you are dealing with poor visibility, above treeline in a whiteout, for example. Again using a partner, send them ahead, but this time rope up so you can follow the rope’s line even if you can’t see them. These methods can take some time (adjust your estimate as needed), but are quite effective.

Go at it, have fun, don’t get lost. Questions, anything unclear, typos, feel free to comment below. I will try to answer or explain as needed.