Basic navigation is a skill that you should learn if you wish to have any hope of surviving in a post-apocalyptic world regardless of whether you worry about having to survive amongst rampaging zombies, in a post-nuclear wasteland, or just your average plague-ridden collapse of civilisation. It also wouldn’t you do you any harm in your real life because you never know when you might find yourself stuck in an unfamiliar place with no cell phone signal or running low on battery power.
So what are the keys to basic navigation? Really it’s all about knowing how to tell which way is north without pulling out some fancy electronic gizmo. The easiest way to do this is to use a magnetic compass. Magnetic compasses don’t require batteries so they’ll never run out of power and you can easily slip one into your pocket without it taking up much space. The best ones for navigation are usually map compasses, which, in addition to telling you which direction is north, can be used to work out everything you need to know get to where you want to go. This puts the functionality of a mapping compass on par with your average sat nav, and at around $10 they’re a lot cheaper!You can use a map compass to help you navigate in two basic ways. The first is to use it to work out a route to where you want to go. To do this, you place the compass on the map and use it to work out which direction (also known as a bearing) you need to go in to get from where you are to where you want to be. Sometimes this will be a direct route; other times, you might need to travel through a series of intermediate waypoints to get there.
Either way, once you’ve worked out your route, you can use the compass to help you navigate along it. To do this, you don’t simply walk along staring at the compass all the time (this is a great way to accidentally walk over a cliff or get chomped on by some lurking flesh-muncher). Instead, you use your compass to identify a clearly-visible feature off in the distance (such as a distinctly-shaped hill) that’s in the direction you want to travel and use this as your target. This way you can keep your wits about you as you move through the landscape (all the better for watching out for pesky zombies trying to creep up on you!). Once you reach your first target, you get your compass out again, and repeat the process until you finally reach your destination.
The second way to use a compass to navigate is to use it to work out where you are if you get lost. This is done by taking bearings to obvious features in the landscape around you, such as mountain peaks, and drawing lines on your map through these features on your map. If you do it properly, and accurately, the point where these lines converge will mark your position. In reality, you usually end up with a little triangle (known as a ‘cocked hat’), but it’ll generally give you a pretty good idea of where you are without having to rely on your GPS-enabled phone.
If you are not lucky enough to have a map showing where you want to go, a compass can still be useful. In particular, through the type of triangulation you can use to work out your own location, you can also build up relatively accurate maps of your local surroundings, and in fact this is the basis of the method used to make maps in the first place. Similarly, you can us a compass to help you travel in a general direction. For example, you may know that you need to get to the coast to have the best chance of surviving, and that it is to your southeast. Even without a map, your trusty compass can help you get there.
What, you might ask, do you do if you lose your compass or if you don’t have one in the first place? Well, there’s other ways of working out which way is north. At night, you can use the position of Polaris, the Pole Star, to tell you where north is (in the northern hemisphere) or the Southern Cross to tell which way is south (if you are in the southern hemisphere). During the day, you can use the position of the sun. In particular, if you are not too close to the equator, the shadows of any vertical object (such as a stick stuck into the ground) will point towards one of the poles a midday (the northern one in the northern hemisphere and the southern one in the southern hemisphere). This means you can use the direction the shadow falls in to tell which way is north. While you might think this is dependent on knowing the exact time, this isn’t the case. All you need to do is mark the end of shadows cast by the same object at two times at least 15 minutes apart. Since the sun moves from east to west (although, technically, it stays still and we move from west to east, but you can ignore this for the moment), a line connecting the first point to the second will run from west to east. Stand with your toes on this line and point your arm directly in front of you and no matter where in the world you are (except the North Pole of course!) it will always be north.
Incidentally, you can also work out other things from shadows, like when local noon is just by examining the length of the shadows of a vertical object. This is because the sun will be directly over head, meaning the shadow cast at noon will be shorter than that cast at any other time of day. The length of the midday shadow of an object of a known height on a specific day of the year can also be used to work out what your latitude is to quite a high level of accuracy (not quite as good as a GPS receiver but close enough). Alternatively, if you know your latitude, and the height of your object, you can use the same information to work out what day of the year it is. Who would have thought shadows could be so useful?
Finally, sometimes you don’t even need to be able to see the skies to know which way is north. There’s certain organisms which can tell you which direction north is (and I’m not thinking of the debate over ‘magnetic’ cows here). Instead, I’m thinking about organisms that like shady conditions. The ones that are most commonly-used in navigation are lichens. Lichens are plant-like organisms that grow on rocks and trees, and because they don’t do as well in direct sunlight, they grow more abundantly on the northern side of rocks and trees in the northern hemisphere and the southern side in the southern hemisphere. This means that in some parts of the world, you can work out which way is north by examining lichen growth on the rocks and trees around you.
So, what does all this mean? Well, as useful as all those modern sat navs and GPS receivers and digital mapping apps are, they’re only navigation aids and you should know how to get around without them just in case you find yourself in a situation where they no longer work. While this could be because a zombie apocalypse has engulfed the world, it could just as easily be because of you’ve got a dead battery on your cell phone.
From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.
To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.