Unfortunately, it's not that simple—measuring distance in steps, especially over rough terrain, is monotonous and tedious. A map can show the total distance to your destination, but it doesn't account for hills, gullies, and other obstacles that add extra kilometers. So, distance can only be estimated. However, there are situations where a rough calculation of time and distance is not only useful but necessary.
Once, during selection trials for a special forces unit, I had to locate a tent that served as an intermediate checkpoint. It stood on top of a windswept, hilly plateau. It was a winter night, with a blizzard raging. I had been on my feet for 17 hours, exhausted, soaked, and hungry. This was the last checkpoint where I had to report. After that, I could descend to the valley where trucks were waiting. Visibility was practically zero as I hunched in a small hollow to check my map.
My destination was only 250 meters away, but I knew that if I missed it, I'd wander for hours in the blizzard. I spent more time than usual working with the map, trying to pinpoint the azimuth as accurately as possible (accounting for magnetic declination) and calculate the number of steps. Setting off, I concentrated on counting my steps, and eventually, sliding down the slope of a small hill, I landed right on the roof of the tent I was looking for! "Well done, Bear," I thought. Although, the officers sitting inside the tent had a different opinion after seeing a size 44 boot suddenly appear through their roof!
Naismith's Rule
This rule helps you estimate how long your hike will take. It was formulated by Scottish mountaineer William Naismith in the late 19th century and is still used today. According to Naismith's Rule, a person covers an average of 5 km per hour on flat ground—then add 30 minutes for every 300 meters of ascent. In other words, a 15 km route with a 500 m climb will take you about 4 hours.
However, various factors influence travel time: your fitness level, backpack weight, terrain type, and weather conditions. Many have tried to make time calculations more precise with complex charts and tables, but the truth is, everyone is different. With experience, you'll learn to gauge how long you need for different types of terrain—use Naismith's Rule as a starting point for your personal calculations. Test it out and adjust it to your walking speed and fitness. Also, remember that groups move slower than individuals, as they must match the pace of the slowest person.
Estimating Distance by Eye
When we look at a distant object, the visual axes of both eyes converge on it. Our brain associates a specific angle of convergence with a specific distance. (If you've ever watched a child trying to grab a toy, you know they often miss at first. This is because their brain hasn't yet learned to correlate the angle of convergence with the object's distance.)
However, various atmospheric conditions interfere with our ability to judge distance correctly. They can make an object seem farther or closer than it actually is. If you want to learn to estimate distance by eye, remember the following rules.
An object appears CLOSER if:
• The day is very sunny;
• The sun is behind you;
• You are standing lower than the object;
• The object is larger than its surroundings;
• There is empty space between you and the object.
An object appears FARTHER if:
• Lighting is very poor;
• The sun is in your face;
• The object is smaller than its surroundings;
• You are lying down;
• The object is located down a street or separated from you by a valley.
Bracketing
Artillerymen use bracketing to determine the distance to a target. When the distance is unknown or only approximate, they fire a shot that overshoots and then one that undershoots. These two parameters help them determine where to aim.
The same tactic can be used on a hike. If you can't determine the distance precisely, you can always assume that the object you're heading towards is, say, no less than 800 m away, but no more than 1 km. And if you have to walk more than a kilometer, you'll know you were wrong.
You can use another method: if you think the object is no closer than 800 m but no farther than a kilometer, take the average between these two values—900 m. Similarly, when planning a route, imagine walking from one landmark to another, not in a straight line. A path marked by noticeable landmarks is much easier and faster to follow than a strict straight line.
"Bracketing" is very useful because it doesn't require precise numbers, which are almost impossible to achieve in field conditions.
Units of Measurement
If you're like most people, you probably find it hard to visualize a distance in meters. If you say a landmark is, for example, 200 meters away, there's no guarantee the person you're telling will be able to picture that distance. The military solves this problem by using comparisons with familiar objects—for example, expressing distance in football field lengths or swimming pool laps. For many people, "two football fields" is much clearer than "200 meters."
Remember, when you're estimating distance by eye on a hike, don't try to be mathematically precise. It's much better to express distance in terms people can easily understand.
The Detail Method
A third way to estimate distance by eye is the detail method, where you judge the distance to an object by the number of details you can discern.
* At 100 m, you can clearly see a person's face.
* At 200 m, skin color isn't visible, but other clothing details are clear.
* At 300 m, the outline of the figure is clear, but most other details are blurred.
* At 400 m, only the outline of the figure is visible.
* At 500 m, the body resembles a cone, the head is poorly defined.
* At 600 m, the body looks like a wedge, the head is indistinguishable.
Of course, all of this depends on visual acuity and visibility conditions.
Step Counting Methods
Knowing the approximate length of your stride, you can estimate the distance you've covered. To calculate your stride length, find a short, measured distance, like a running track, and take 100 normal steps along it. Divide the distance covered by 100 to get your average stride length. Repeat this several times to get an average. Now you know how much ground you cover in one step.
I prefer this method: walk a known distance, say 100 meters, and count your steps. Repeat this several times and determine the average number of steps. Now you know how many steps you need to take to cover 100 meters.
Of course, these methods aren't perfect. On the trail, stride length depends on the terrain—your steps shorten when going uphill. But knowing your stride length is always useful. Someday it might get you out of trouble.
Counting steps is tricky, especially over long distances. Get distracted for a minute, and you'll lose count. You can use a pedometer, a mechanical device that counts steps via a pendulum swing. However, it's unreliable in rugged conditions.
The military uses a pace counter or step counter—you might have seen this device on airplanes. Stewardesses use it to count passengers. After every ten steps, you press a button. The counter tallies the presses—ten presses means 100 steps. If you don't have a counter, fill a pocket with small stones. After every 100 steps, transfer one stone to another pocket. Counting the stones tells you the distance covered. You can also use beads on a string, like an abacus.
The Formula for Successful Navigation
Finally, concerning the use of map and compass: to get accurate information, you must account for various factors. Don't rely on just a compass bearing alone.
The key factors that help you always know your location are: Bearing, Distance, Time, Landmarks, and Cues that you're off course.
Bearing – What bearing should I follow?
Distance – How far do I need to go?
Time – How long will it take to reach the next point (using Naismith's Rule)?
Landmarks – What natural features will I encounter (e.g., a stream on the left, a forest on the right)?
Cues – What will tell me I've gone wrong (e.g., if I start descending, I've gone too far)?
I always use these principles, and they have saved my life many times!
Next guide: Global Positioning Systems Previous guide: How to Read a Map Correctly and Plan the Perfect Route You can view the full list here: Survival Guides for the Mountains
