Talking about navigation, it is essential to know how to find your way. The compass is indeed the most precious tool when you are on the move. The watch and the alarm clock come just after, because they can help you to direct north or south. Of course they can indicate the elapsed time as well as estimate the distance covered, another essential element of navigation. It exists different types of compass ; any can make the job as long as they’re attracted by the Earth magnetic poles. If you don’t have a compass in your belongings, you always can find your way in an approximate manner. You can do so referring on the sun and the stars as well as observing the animals and vegetation.
The needle of a compass indicates magnetic north and magnetic south, the two natural magnetic poles of Earth. Imagine the Earth like a big sphere that would contains a vertical magnet ; the poles are up and down this magnet, they are the exit points of magnetic charge. There are many kinds of compass. Hikers can settle for a simple pivot compass, in case of emergency. But they would prefer a Silva compass for navigation and orientation. Prismatic compasses have integrated prisms and allow you to take up positions ; they are robust and precise. Some of these compasses contain mirrors, instead of or in addition to prisms ; they are the most expensive ones. A Silva compass is enough to direct correctly ; its use is simple and helps to avoid mistakes.
The Silva Compass
A compass with a protractor allow you to take positions on a map, without having to move the compass. No need to carry a separated protractor or to do some mental arithmetic to find your position.
There are several types of maps, all designed for different uses. Choosing the right map can be vital, especially when you enter a foreign territory. You will need high scaled maps covering all the region that you’re going to visit and the places that you plan to go on foot. The maps with a 1/50 000 scale are ideal for hikers. Maps are usually divided by a grid of lines spaced 2cm apart, i.e. 1km on the ground, with two coordinates from 0 to 99. Some maps are inaccurate for several reasons. Correct them as you progress and allow for a margin of inaccuracy in your route.
How to read a map
Relief is shaped by the rivers that run through it, creating ridges, hills and valleys. Man-made structures, such as roads, change very quickly. To understand the landscape using a map, start by identifying rivers and then valleys and landforms. They indeed change very little over the life of a map.
Different types of landscapes
A valley, and the river that dug it, is materialized on a map by lines describing complicated convolutions at equal altitude. These lines indicate the exact shape of the valley – and particularly, sections that are not visible from the observer that navigates them on foot. The altitude is indicated by numbers written along the lines.
A map is giving a flat representation of all the mountain. A large part of this mountain isn’t visible from a single viewpoint on the field. You have to imagine the invisible part from the point that you’re located at. The altitude is indicated as if it were marked on a mountainside.
The pass is a depression between two peaks in a mountain range. If you happen to be at the foot of one of these two mountains, in the axis of one of the two peaks, you only see one of them. The pass is usually represented on maps by two circles surrounded by contour lines.
Rivers are often separated by ridges of hills or mountains. On a map, ridges are drawn like fingers, on both sides of the hill. It is often easier to walk on ridges of hills than in the valleys, especially in the regions with a thick jungle.
Inclination of the terrain
Contour lines connect points of the same altitude. The elevation of certain contours is also recorded, such as on the hillside along the slope.
It is important to know the level curves. Large gaps can conceal cliffs.
Usually, the slope between contours is gradual. When the contours are very close together, they indicate steep slopes.
When you're at the bottom of a convex slope, you can't see the top. The contours are close together at the bottom and move away towards the top.
The inclination of a concave slope is gentle at the beginning and the top is visible from below. On a map, the contour lines get closer and closer to the top.