If you’re navigating through unfamiliar terrain, having a map is as valuable as gold dust. You may have planned your routes by them and will be relying on them throughout the course of your expedition. However, a map is next to worthless if you don’t know how to decipher it. This article will outline the basics for map reading.
Scale: First, your map should be at a scale which is useful. For instance, having a small-scale, detailed map will be of no use to you if you simply plan to drive through an area. In the same way, if you are on foot, then having a less detailed map can be next to useless. It is also important to understand the scale bar. This bar will show the size at which a kilometer or mile is shown on the map and is usually expressed as a ratio. For instance, 1:50,000 means that each measure on the map is 50,000 times smaller than the true distance. This will allow you to use the map to determine distances.
Contour lines: Because a map is 2D, different heights of terrain must be indicated using contour lines. These show the altitudes of the land and are recorded at regular intervals – usually 50ft (15m). Each point on a contour line’s ring is hypothetically at the same height, which is indicated with a number (in feet or meters). This tells you how high above sea level the terrain is. In general, contour lines which are closer together indicate a steeper gradient. However, it’s important to bear in mind the scale of your map so that you don’t over- or underestimate the gradient.
Key: The key will explain what the symbols used on the map refer to. These will represent a range of manmade and natural structures, types of land (woodland, swaps or beaches, for example), rivers and water. There are some features which are not depicted to scale. For instance, roads, paths and waterways will often have a standard width, which may not represent their exact measurements.
Grids: Maps will have horizontal and vertical grid lines which divide the map into squares. This division is either based on longitude and latitude or may be individual to the particular mapping authority. Grids will allow you to more quickly determine distances, since they are usually at a comprehensive scale (for example, the distance from left to right is often 1 kilometer). These grids will also allow you to explain to other exactly
Orientation: Important to remember is that the grids on a map do not necessarily indicate north and south, though they may provide a rough indication of this. You will need to also be aware that your compass does not point to true north, but to magnetic north. Most maps will also indicate magnetic north. The deviations between these can help you map-read your way across a landscape, as can taking note of your surroundings in relation to features on the map.
Roman is a former EMT living in NYC and co-founder of Ready To Go Survival. When he’s not working on the next big thing for preppers; he likes to go camping, shoot stuff at the range, archery, and ride his bicycle excruciating distances.