To use a map you need to look at your surroundings and locate yourself. Then, you can trace a course and follow the path. A compass in not necessary, but extremely recommended.
I’ve choosen a geat place in the Rocky Mountains to show you how to use a map. You can follow along this guide by downloading this map. The starting point is Joe Mills Mountain, and we want to go to Fern Creek’s source lake.
First, I will show you everything you need to know on how to interpret a map. Then, you will learn how to use a map.
Table of Contents
How to read a map
Some maps feature a compass rose that indicates the map’s position. If there is none, then the top is north.
Also called Map Key. It’s a list of symbols that help you interpret the map. They represent things like landmarks, area borders, environmental features, roads, or towns.
The legend also contains information such as its scale, contour line intervals, or magnetic declination.
The map scale is the relation between the distances in the map and the real distances.
For example, a scale of 1:100000 means that 1 inch on the map is 100000 inches in the real world. So, if you measure 7 inches (18cm) on the map, the real distance is 11 miles (18km).
Maps also have a representative scale. It’s a little bar that measures a specific distance, for example, 1 mile (1.6km).
It’s a quick way to get a sense of real distances. If can fit 3 bars between two points on the map, it means that they are approximately 3 miles away.
- Large scales: Have greater detail and cover a particular place. They are “closer” to the ground. (eg. 1:10000)
- Small scales: Have lower detail but include more terrain. They are “farther” from the ground (eg. 1:500000)
They show the shape and steepness of the terrain. Each one of those circles is at a certain height, so you can think of them as layers one above the other.
There is always the same height between every two lines. So when they are close, the terrain is steep. But when they are wide apart, the terrain is a gentle slope.
Usually, the height from one contour line to the next is 40 or 80 feet (12 or 24 meters), and remains the same for the whole map. In the map that we are using, the legend indicates 40 feet (12 meters).
When you see a circle with no contour lines inside, it is a peak. Same way, the zones between circles are valleys.
Index contour lines
There are thicker lines every five contour lines. These have a number that indicates their exact height, so it’s easier to know their surroundings’ elevation.
In some cases, contour lines have little tick marks. It means that they are reversed, so each circle is lower instead of higher.
Knowing longitude and latitude is important for knowing your position on long trips. You will locate them at the sides of the map, vertically and horizontally.
You can measure in miles or kilometers when talking about short distances. But when traveling long distances, you have to take into account the earth’s curvature.
Longitude and latitude are polar coordinate units. They measure angles instead of distances. That’s why they are in degrees, minutes, and seconds.
Your east or west position from the Prime Meridian. It measures how far you are from the Prime Meridian (Which passes through Greenwich, England).
You can think of it as your horizontal location in the world. Greenwich is at 0º, and New Orleans is at -90º longitude.
Parallels of Latitude:
Your north or south position from the Equator. It measures how far you are from the Equator.
You can think of it as your vertical location in the world. The Equator is at 0º, and the North Pole is at 90º latitude.
How to use a map
Make sure to assign one person for the navigation. Locating yourself and the path forward requires concentration and interpreting both the map and your surroundings. It’s best to have a single person in charge to avoid confusion and discussions.
However, do not hesitate to ask for help and a second opinion in case of doubt.
#1 – Find the real north
The real noth is not where your compass signals. The angle between the two is called declination.
If you take the magnetic north (Which is the one your compass catches) you will deviate about 100 feet (30 meters) for every mile (1.6km) you walk. Just with a single degree of declination!
In the US, declination goes from -20º to +20º, so you can deviate up to 2000 feet (600 meters) for each mile.
If the declination is positive, it means that your compass will deviate to the east of the real north. It will point to the west if it is negative.
Most topo maps show the declination of that area, but it varies over time. Keep them updated and check the National Oceanic and Atmospheric Administration (NOAA) magnetic declination.
You can adjust most compasses for declination by rotating the orienting arrow.
Once you know where the north is, you can orient your map and start looking for landmarks.
#2 – Figure out where you are (Triangulate)
Without a compass
Traveling without a compass is harder. You rely on your ability to orientate and observe your surroundings.
First, figure out where the north is. If you are in the northern hemisphere, it will be in front of the midday sun. Turn your back on it, and you will be looking at the north.
Then, start looking for at least two landmarks and identify them on your map. Compare your view’s position with the map’s landmarks. You will get an approximate position or direction of where you are. To fine-tune, look for near environmental features and identify them on the map.
With a compass
Look around you for a landmark, like a mountain or a lake. Then, find it on your map.
Point to the landmark with your compass and check its angle.
“Save” this number by rotating the compass bezel until it lines up.
Place the compass over the landmark on your map and rotate it at that same angle. Trace a line.
Repeat with one or two more landmarks. Where the lines join is your approximate location.
#3 – Take a Bearing
Draw a line between where you are and your destination. Align your compass with that line.
Rotate the bezel to align the orienting lines with your map’s north. You have “saved” your bearing into the compass.
Take the compass and rotate yourself. Keep the needle aligned with your bezel’s saved position. You can now walk forwards keeping the needle aligned.
#4 – Plot your course
Once you know where you are, locate your destination on the map. Keep in mind that the fastest path is not always a straight line. Look for trails and roads, and try to avoid climbing peaks if you can just get around them. This is where the contour lines come in handy.
Also, measure your approximate distance using the map’s scale to plan for stops.
#5 – Create checkpoints
It’s important to follow a path to not get lost. Plan in advance where to stop and what landmarks you must encounter. Once you reach them, mark them on the map.
It is also a matter of safety. It will allow you to get back on track if you deviate, warn others and turn back in case of necessity.
What to do next
Now that you know how to use a map, it’s time embark in new adventures. You can use this knowledge in activities such as hiking, skiing and even diving! Always plan your trips ahead so you can focus on the journey itselt.
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