The most important aspect of trekking or hiking is knowing where you are, and where you are going. I feel that everyone who enjoys the outdoors should learn and practice navigation. This is especially important if you travel solo. However, even in a group, relying on someone who knows the trail is not good enough. Sometimes circumstances could force you to get separated from your group and lose the trail. According to a study by SmokyMountains.com, wandering off trail is the number one reason, ahead of bad weather, that hikers get lost and require rescue.
In this article, we will take a look at the following navigation techniques:
- Navigation by observing topography and maps
- Navigation using GPS on a smartphone
- Navigation using a map and compass
- Celestial navigation
The more options you have for navigating, the better. Your ability to navigate shouldn’t depend on a single device or technique. So, let’s get started!
The Power of Observation
In my opinion, the most important navigation technique is to pay attention to your surroundings. As you walk through the wilderness, observe everything that is around you. Observe the trees, the rocks, the mountains, the streams. These features can be important navigation aids. Pay close attention to what they look like, and how they are different from similar features around you. Once in a while, turn back to see the terrain from the perspective it would appear during your way back. The same features look different from a different perspective.
Whenever I go to an unfamiliar trail, I take a few moments to observe the things around me. Then, as I walk, I continue this process to develop an “internal map”. This process also helps me stay connected with my surroundings.
Next, try finding the features that you see around you on a topographic map (we will talk about topographic maps later in this article). Using this technique, you won’t even need to pull out your GPS or compass to keep track of your position. Using a map and continuously observing the terrain is often sufficient.
Navigation using GPS on a smartphone
Using a GPS device is probably one of the easiest ways to navigate. Most of us use smartphones that are already equipped with GPS capabilities. So, there really is no excuse for not learning to use one. GPS based navigation works even when you are outside network coverage. However, you do need an internet connection to download maps. So, make sure you download offline maps prior to your trip.
There are many apps that can be used for offline navigation on a smartphone. Recently I have been using OsmAnd+ and I’ve found it to be quite capable. You can use this app to download topographic maps, plan routes, see the gradient of slopes, etc. It’s a lot more suited for trekking compared to Google Maps (which comes preinstalled on most Android devices). However, even with Google Maps, you can download offline maps.
Some more apps/tools to consider:
- Gaia GPS
- AllTrails - this app contains GPX files for many popular trails.
- GPX Studio - a free online tool for preparing your own GPX files.
I won’t cover how to use apps for navigation, as that is beyond the scope of this article. Here is a complete guide by India Hikes on using GPX files with the Gaia GPS app: A Complete Guide on How to Use GPX Files.
- Make sure you carry extra batteries or some charging device for your smartphone.
- Use a sturdy case that will protect your smartphone.
- Whenever you reach a campsite (or other important landmark), save the location on your app. This way, if you wander off, you can find your way back.
Using a map and compass
Using a GPS device is easy and convenient. However, as I said earlier, your ability to navigate shouldn’t depend on a single device or technique. What would you do if your GPS device runs out of batteries, or your waterproof device isn’t as waterproof as you had hoped?
A compass is a simple tool and doesn’t require any batteries. I believe every outdoor adventurer should learn the art of using the humble map and compass. It may seem a bit daunting at first, but it gets easier with practice. I’m sure you will find learning this skill quite rewarding. Moreover, you will feel like the old-time explorers and adventurers who relied on nothing but a map and compass on their adventures! There is something very satisfying about using our planet’s magnetic fields to guide us. Using a map and compass also requires paying more attention to your surroundings compared to a GPS. With a GPS, you just have to follow a line. However, the more options you have, the better. So, don’t ditch your GPS device. Keep this unreliable luxury as a backup.
What type of compass to use?
There are many different types of compasses. The one best suited for use with maps is called a baseplate compass. These have a transparent base, and a rotating compass housing marked in degrees.
Map and compass navigation at Rola Kholi on the Bhrigu Lake trail
There are many companies that manufacture them such as Suunto, Silva, Brunton, etc. At Decathlon, you can find baseplate compasses made by Geonaute that aren’t too expensive and will work just fine. I have been using a Suunto M3 for many years, and it has been a dependable tool.
A typical baseplate compass contains the following parts:
- Transparent baseplate: The transparent base plate contains straight edges for use with a map.
- Direction-of-travel arrow: This tells you which direction to follow when you’re taking or following a bearing.
- Bearing index: This is for reading the current bearing.
- Magnetic needle: This needle rotates and the red end of the needle always points towards magnetic north.
- Orienting arrow: The orienting arrow is aligned with the magnetic needle to find the bearing to a target.
- Orienting lines: The orienting lines are used to align the compass housing with the meridian lines on a map.
- Rotating housing: The rotating housing is used to align the orienting lines with a map to get a bearing. This is also used to “box the needle” (discussed later).
Baseplate compass anatomy
What is a bearing?
A bearing is the direction of one place from another, measured in degrees with respect to true north.
A compass is used for the following basic tasks regarding bearings:
- To take a bearing between two points on a map.
- To take a bearing to a location in the field.
- To follow a bearing in the field.
- To plot a bearing on a map.
We will talk about each of these in the coming sections.
The curious case of two north poles (correcting for declination)
Our planet has two north poles - the geographic north pole (aka “true north”), and the magnetic north pole. A compass needle always points towards the magnetic north pole. The deviation of the compass from true north is called “declination”. Declination has been a nuisance for navigators for centuries because it varies with location and time. So, before you begin using your compass, you should always check what the declination is in your area. You can use this online tool to find the magnetic declination - https://www.magnetic-declination.com/. Topographic maps typically mention the declination near the bottom. By convention, declination is positive when magnetic north is east of true north, and negative when it is to the west.
2020 World declination map (published by NOAA)
As you can see in this map, the magnetic declination across India varies by only about +/- 2 degrees. So, the error is not significant and can be ignored in most scenarios. Of course, if you are walking a very long distance in featureless terrain, this error would add up.
You can correct declination with some arithmetic:
- For easterly declination, subtract the declination from the true reading to obtain the magnetic reading. Magnetic = true - easterly declination
- For westerly declination, add the declination to the true reading to obtain the magnetic reading. Magnetic = true + westerly declination
Protip: Some compasses have a declination correction screw that automatically corrects the error. If yours has one, make sure it is adjusted. This way, you don’t have to perform any mental arithmetic on the field.
Topographic maps are the best type of maps for trekkers. These maps show the three-dimensional terrain of a region on a two-dimensional map. To depict topography, they make use of “contour lines” that represent constant elevation levels.
Example of a topographic profile
Contour lines: The most important aspect of a topographic map is its array of contour lines. Each line represents a constant elevation as it follows the shape of the landscape.
Contour interval: The contour interval is the difference in elevation between two adjacent contour lines. Every fifth contour line (called an index contour) is darker than the other contour lines and is labeled with the elevation.
The closer together the contour lines are, the steeper the terrain is, and vice-versa. Some of the features that you can identify by looking at the contour lines are:
- Flat areas: No contour lines.
- Gentle slopes: Widely spaced contour lines.
- Steep slopes: Closely spaced contour lines.
- Cliffs: Contour lines extremely close together or touching.
- Peaks: A concentric pattern of contour lines with the peak being the innermost circle at the highest elevation.
- Ridges: Contour lines in the shape of Us or Vs that point downhill.
- Valleys, ravines, gullies: Contour lines in the shape of Us and Vs that point uphill.
See how many of these features you can find in the topo map of Bhrigu lake below.
Topographic map of Bhrigu Lake
Getting topographic maps
Topographic maps are not easily available in India as far as I know. However, you can generate topo maps using free online tools such as CalTopo - https://caltopo.com/
You can even import a GPX file into CalTopo to overlay the trail on the map. For my recent Bhrigu Lake trek, I was able to find a GPX file on AllTrails.
When printing a map using CalTopo, it asks you to define the map’s scale. The scale determines how much land area is visible on the map. If the scale is 1:24000, it means 1 inch on the map equals 24000 inches (2000 ft) in the real world. Smaller scales (such as 1:24k or 1:25k), contain more detail but cover a smaller area. A larger scale (such as 1:50k) covers a larger area and may be better for planning multi-day routes.
I guess it doesn’t really matter which scale map you are using as long as you know how to use it. The map should contain enough detail for the activity you are doing. I generally print multiple maps on A4 size paper and use a mixture of 1:25k and 1:50k maps. I make sure that the maps contain enough geographical features that I can use for navigation.
- When visibility drops, many of the geographical features that you see on your map may not be visible in the real world. For example, on the Bhrigu Lake trek, I realized that Patalsu Peak and Mt. Hanuman Tibba were not visible when the clouds rolled in. So, even though these peaks are big and easily identifiable, they may not always be visible. So, I would suggest paying attention to features that are closer to you, even if they are unnamed on your map.
- Carry your maps in a ziplock bag to keep them dry. Keep the bag somewhere where it is easily accessible. I like to carry my maps in the waist strap pocket of my backpack or in the patch pocket of my trousers.
Orienting a map with a compass
By orienting a map, you are positioning it so its north is actually pointing towards north. This helps you relate what you are seeing on the map, with your actual surroundings. Here’s how you orient a map:
- Hold your map horizontally.
- Place your compass flat on the map.
- Rotate the map until the northern upper edge is aligned with your compass needle. The red end of the compass needle is where magnetic north is.
Navigating with a map and compass
To determine how to get from point A to point B on the map, you first use your compass to determine the direction of travel on the map. Then, you transfer that direction of travel to the real world.
1. Place the compass on the map between the starting point (A), and your target (B).
Taking a bearing from a map (step 1)
2. Rotate the compass housing until the orienting lines inside the capsule are parallel to the meridian lines on the map (with N on the bezel pointing towards north on the map).
Taking a bearing from a map (step 2)
3. Hold the compass at waist height and turn until the red portion of the magnetic needle is inside the red orienting arrow. (This process is sometimes referred to as boxing the needle.) Remember to compensate for declination as needed.
Finding the direction of travel
4. Find a visible target in the direction your compass is pointing and walk towards it. Repeat steps 3 and 4 until you reach the destination.
Finding your location on a map
You can use a compass to find your location on a map (similar to a GPS)! This works using a technique called triangulation. Here’s how this works:
- Find a landmark on the map that you can identify in the real world. Use your compass to take a bearing to that landmark. This is done by pointing the direction-of-travel arrow towards the landmark and “boxing the needle” (as described earlier).
- Read the bearing at the index line. Correct for declination if necessary.
Taking a bearing
- Place the compass on your map, and align the orienting lines on the compass with the north-south meridian lines on the map.
- Move your compass so that the top end of one edge ends at the landmark. Make sure the orienting lines are aligned with the meridian lines as you do this.
- Draw a line along the edge of your compass from the landmark. You are somewhere along this line.
- Repeat this process by taking a bearing from another landmark and drawing it on your map.
- Where these two lines intersect is your approximate location.
Using two peaks to find our location on the Bhrigu Lake trail
Getting from one place to another usually just involves watching the landscape and occasionally glancing at your map to stay oriented. If there are trails or natural features that you can use, you often don’t even need to use a compass. However, if you can’t see your objective, or you are moving through terrain that lacks sufficient features (snow, dense forest), it is easy to get disoriented. In these situations, you can use a compass to take a bearing from a map, and follow it to your destination. However, often times a straight-line path to your goal won’t exist in the wilderness. Let’s look at a few of these situations and strategies for dealing with them.
When following a compass bearing, you may encounter an obstruction on your path such as dense brush, rocks, or a lake, that will prevent you from following a bearing. Let’s look at a few ways to deal with them.
If you can see across the obstruction:
If you can see over the obstruction, find an identifiable target (such as a tree or rock) that lies exactly on the bearing line. Then move over the obstruction or around it (whatever is easiest) and get to that target. When you get to that target, you can be confident that you are still on the bearing line. You can continue following the bearing as usual.
If you can’t find an easily identifiable target around the obstruction that lies on the bearing line, you can send a trekking buddy to the other side of the obstruction. You can guide them left or right until they are exactly on the bearing line. Then you walk to your buddy and continue following the bearing as usual.
If you are trekking alone and can’t find an easily identifiable target past the obstruction, you could create a temporary landmark at your current position by piling stones or logs that you can see from the other side of the obstruction. Then, walk around the obstruction and take a back bearing to the landmark you created. A back bearing is simply the opposite direction of a bearing. In degrees, this would mean 180 degrees off from the bearing. For example, if you are following the 90-degree bearing (east), the back bearing would be 90 + 180 = 270 degrees (west). If the original bearing is greater than 180, you subtract 180 to get the back bearing. If you are traveling 270 degrees (west), the back bearing would be 270 - 180 = 90 degrees (east).
Tip: You don’t need to perform any mental arithmetic to get the back bearing. Your compass can do that for you! Keep the original bearing set on the compass, and rotate until the south-seeking end of the magnetic needle (which could be black or white) is inside the red orienting arrow. This is just the opposite of how you typically “box the needle”. This technique can also be used to double-check if you are correctly tracking a bearing line by taking a back bearing to your starting position.
If you cannot see across the obstruction:
If you can’t see around the obstruction (such as a hill), you can use a different strategy. After you approach the obstruction, travel 90 degrees left or right and walk until you clear the obstruction. Count your steps as you walk perpendicular to the intended course. Then, walk past the obstruction following the original bearing. Finally, turn 90 degrees again and walk the same number of steps to return to the original course. The turns don’t need to be 90 degrees. It could be anything that you can use to return to the original course. The image below explains this process:
Navigating around an obstruction when you can’t see across it
Deliberate Offset (or “Aiming Off”)
Suppose your campsite is next to a river, and you are following a compass bearing to return to it. If you are off by a couple of degrees, you will reach the river, but may miss the campsite. If you can’t see the campsite (because of fog, dense vegetation, etc), you’ll have to guess which direction to walk to find your campsite. You may end up walking in the wrong direction before you realize your mistake. In situations where your destination is next to a long-running feature (such as a river or a road), you can deliberately aim off to remove the guesswork. For example, you could aim 10 degrees to the left or right of the campsite. When you reach the river, there will be no doubt which direction to walk.
Aiming off to avoid missing the target
There are many navigation techniques that rely on using celestial bodies to determine direction. These techniques may not be as accurate or convenient as using a GPS or a compass, but it is a good idea to learn a few of those techniques in case you ever need them.
Using the Stars
If you have a clear view of the night sky, you can look at the stars to navigate! This isn’t as difficult as it may seem. Most of the stars in the sky move with time. However, there is one star that doesn’t appear to move! This star is called Polaris (or the North Star). It appears directly above the North Pole. For thousands of years, countless sailors and adventurers have relied on Polaris to navigate!
Polaris is at the tip of the Little Dipper constellation. However, since the stars of the Little Dipper are not as bright as Big Dipper (aka Ursa Major), it is often easier to use Big Dipper to find Polaris. Big Dipper kind of looks like a big saucepan. After you find Big Dipper, find the two stars at the end of the saucepan. These are called the “pointer stars” as they point towards Polaris. Polaris will be about 5 times the distance between the two pointer stars in the direction that they point.
Finding Polaris using Big Dipper (source: https://www.youtube.com/watch?v=7DjJ3r4XG0E)
Keep in mind that Big Dipper will rotate in the sky depending on the time and season. It rotates anti-clockwise about Polaris. However, the relationship between Polaris and Big Dipper will not change, and this constellation will always lead you to Polaris.
Watch this video to learn how to find Polaris
Apparently, dung beetles also use stars to navigate!
Using the Moon
A quick (but not so accurate) technique to find south using the moon works as follows: Imagine a line that connects the horns of the moon and extend this line down to the horizon. In the northern hemisphere, this will give an approximate indication of south (or north in the southern hemisphere). This technique works best when the moon is high in the sky and not too close to the horizon.
Using the Moon to find south
Using the Sun
Here’s one method to determine direction using the sun: Place a stick in the ground at some point before the middle of the day. The stick will cast a shadow on the ground. Place a stone at the end of the stick’s shadow. Using a string or rope attached to the stick, draw an arc around the stick which has a radius equal to the length of that shadow. As the day progresses, the shadow will shorten and move away from the arc. When the sun starts moving towards the west, the shadow will lengthen and touch the arc again. Place another stone where it intersects the arc. Draw a line between the two stones and you will get an accurate east-west line.
We covered a lot of navigation techniques in this article. Next time you go on a trek, try a few of these techniques. Practicing navigation techniques on a familiar trail is a good way to learn without the risk of getting lost. With practice, you will get the hang of it. I’m sure this makes your trekking experience even more interesting. Keep exploring!