by Brian Griffin June 19, 2019
I think most of us who have spent time in the out of doors are pretty familiar with the concept of a compass. The liquid-dampened versions came along in the mid 1930s when Suunto founder Tuomas Vohlonen found a way to fill his compass capsules with liquid in mass production. So most of us have grown up seeing that type. However the very first primitive compasses, made of load stones, date back a couple of thousand years to the Han Dynasty in China, and the first dry compasses predate the Dark Ages of Europe. For the most part all compasses – old school and newfangled – perform one primary function, they point to magnetic north.
Today we have a lot of options to choose from when it comes to picking a compass. From the large, and sometimes rather heavy, lensatic compasses to smaller map and sighting compasses, on down to tiny button compasses that take up very little space in a small kit. Obviously the smaller and less complex the compass, the less accurate it is going to be for long distance navigation, but in many cases all we really need to know is a general direction.
I don't have an actual map compass per se, to use for an illustration here. Mainly because I much prefer mirrored sighting compass for times when I am carrying a full size compass, and I no longer own a plain map compass. However I think most people are probably pretty familiar with them by now. If you look at the above image, a map compass is essentially a sighting compass with the mirror and sighting elements left off. I prefer to have the mirror handy for multiple reasons, and some of them have nothing to do with land navigation.
Some people do prefer to carry the map compasses, usually because they are lighter and take up less space. I understand that line of thinking, it's the same reason I carry button compasses in my contingency kits. However I don't use those with maps for serious navigation. If the intended use is map and compass work while trail blazing, then I prefer to take a sighting compass and cut weight some other way. By switching to a lighter knife and a smaller sighting compass I can lower my overall weight, and still have the sighting compass that I feel better about carrying.
I suppose most have thought of the mirror on a sighting compass being used as a signal device, and obviously it will work for that. You can use them to signal for help if you are stranded in an open area or just to signal back and forth between team mates to keep up with each-other's positions. You can even use them to shine sunlight into a darkened hole or cave to look around inside before entering. For me personally, the times I have been the most glad to have the mirror were when I had foreign matter in my eyes, and I was all alone deep in a forest. The above photo was taken to illustrate similar text for a piece I wrote ten years ago. I was deep into the Smoky Mountains in July, and I had used the mirror on a Suunto MC2G for extricating more than a dozen suicidal gnats. They had flown into my eyes while I was traveling through a marshy area. I can tell you from experience, the larger the mirror you have, the easier this task is to perform.
There are also ways to determine direction without the benefit of a compass. More primitive ways that involve a better understanding of the natural world, and that is actually what this article is about. There is an old saying that “moss grows on the north side of a tree”. This is an oversimplified version of a true statement. Which is to say that moss usually grows thicker and more lush on the north sides of trees or rocks because moss prefers shade over sunlight. In the above image you can see the moss is heaviest on the vertical northern side of the rock formation, and not so much on the exposed upper sections or on the eastern side. If you walk into a relatively flat and open wooded area where moss is known to grow, then and turn your line of sight a full 360 degrees, you may notice the growth of the moss being much more prevalent in one direction and much less so in the exact opposite direction. In the direction you see the most moss you will be looking south at the north sides of the trees and rocks. In this case north is behind you, east is to your left and west is to your right.
Conversely most trees prefer sunlight over shade, and you can often use their growth patterns to determine direction. If you look closely at trees in more open areas, where all sides are exposed to the sky, you can see how they are usually more lush and filled in on one side and more sparse looking on the exact opposite side. Note the fuller brighter look to the right sides of the trees in this image. As you can see by the compass I am facing East by slightly South-East, and south is to my right. You can also note how the foliage is sparser and more shaded on the left side of the image, which is the northern side of the trees where the sun never shines.
Another way of determining direction is by using the shadow of sun-dial compass. I think most instructors tend to teach this method via a pointed stick driven into the ground as the means of casting the shadow, and two stones to mark the points with. However there are other ways to approach it if you happen to be on a hard surface. Any object that can free-stand such as a water bottle or a flashlight will work to cast the shadow, and any two small objects such as pebbles or coins can be used to mark the points. You can even lay a pointed stick, pencil, or ink pen on top of a larger object in order to create a finer point of shadow for marking.
It should be noted here that in order to get the most accurate reading possible from this method, it should be started shortly before the sun has reached its zenith, and concluded at the same point in time past the zenith when the shadow has reached the opposite location on the other side of the caster. Over the course of a day the shadow travels in a slight arc around the north side of the caster from west to east. Thus two points lined up after a period of time in morning will create a line that runs from South-West to North-East. While two points lined up after period of time in the evening will create a line that runs from South-East to northwest. Obviously during the very earliest and very latest hours of daylight, the sun itself makes determining direction very simple. However near noon when the sun is high in the sky, a point from one amount of time before the zenith lined up with a point from the same amount of time after it will create a line that runs directly east to west.
One of the more obscure methods of determining direction requires two things. First that you be familiar with the prevailing winds in your geographic region, and secondly that you are in an area open enough that the prevailing winds aren't being redirected by terrain features or buildings. In situations where both of these requirements are met, then you can determine direction by simply looking at the disposition of the taller plants a field. Because they will have been effected by the prevailing winds during their entire growth cycle, and will be leaning in the direction it blows.
At night there are a few ways the constellations in the sky can help you determine direction on a clear night. Points in several constellations can be lined up to point toward Polaris the pole star, or the north star some call it. The easiest and least complicated one in the northern hemisphere is to use Ursa Major, the big dipper, to locate Polaris. An imaginary line, drawn between the two forward stars of the big dipper, creates a line that points to Polaris almost as if Ursa Major is trying to capture it. This line doesn't point north, it simply points to the star that sits above the north pole. But if you are familiar with it, you can use this method to roughly determine north even when terrain features block Polaris and parts of Ursa Major from your sight.
I should point out here that the above information applies as-is to locations in the northern hemisphere. However most of it can also be applied to the southern hemisphere as well, just by using some common sense. The difference would be that things would switch places. The shade loving plants would grow thickest on the southern sides of trees and rocks, and the trees would grow fuller on their northern sides. At night you would have the Southern Cross constellation by which to determine direction. On the equator things might be a little trickier during the day looking at shadows and foliage, but at least at night you have both Polaris and the Southern Cross in the night sky to help determine direction, and that's pretty cool.
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