Map Reading Basics 2
MAP READING MADE EASY
In the last two posts we have explained map reading basics and the features on a compass. Today we are going to try and explain how to use a map and compass together, to help you navigate.
HOLD THE COMPASS CORRECTLY
First you must know how to hold the compass correctly. Hold the compass, flat, in the palm of your hand and in front of your chest. (use this method while travelling or following a bearing.) If you are using the compass with a map then the map should be on a flat surface with the compass on top to get a proper reading.
FIND OUT WHICH WAY YOU ARE FACING
For quick and easy exercise to find out which way you are facing, look at the red magnetic needle. This is pointing (magnetic) North, it will swing one way or another unless you are actually facing North at the time.
- Turn the compass dial until the orienteering arrow lines up with the compass needle, thus pointing them both North. Then look at the direction of travel arrow, this is now showing you which way you are facing. If it is between South and West on the dial then you will be facing roughly SouthWest.
- For a more accurate reading, look at the degree markers on the dial, (these are marked every 2º) if the index line is on 230º you are facing 230º SW
TAKING A BEARING
When out hiking you should, periodically, take a bearing to ensure you are going in the right direction. To do this, point the direction of travel arrow at where you want to walk to, unless your heading North the needle will spin off to one side. Then twist the dial until the orienteering arrow lines up with the compass needle, once aligned this will tell you where you direction of travel arrow is pointing. Now add or subtract the amount of declination. This is now your bearing. Keep on taking a bearing at regular intervals. The number of times you do this depends on the landscape around you. If it's possible to see a point in the distance to walk to, then you might only need to take a bearing every now and then, or if you have to change course to cross a river for example. If you are in a forest you will have to take a bearing more often as you might not have any landmarks to help guide you. You can then walk along the bearing. To do this hold the compass the correct way, then turn your body so that the orienteering arrow and compass needle lineup, then move along the bearing. Do this as often as you think you need to, but take care not to turn the compass wheel, as you will lose you bearing. If visibility is limited and you cannot see any distant objects, use another member of your walking party (if applicable). Stand still, then ask them to walk away from you in the direction indicated by the direction of travel arrow. Call out to them to correct their direction as they walk. When they approach the edge of visibility, ask them to wait until you catch up. Repeat as necessary.
TO PUT DIRECTION OF TRAVEL ONTO YOUR MAP
Place your map on a horizontal surface, then place the compass on the map so that the orienting arrow points to true north on the map. If you know your current position on the map, slide your compass around so that its edge passes through your current position, but its orienting arrow continues to point north. Draw a line along the compass edge and through your current position. If you maintain this bearing, your path from your current position will be along the line you just drew on your map.
HOW TO TAKE BEARING FROM YOUR MAP
To find out which direction you need to travel to get somewhere, place the map on a horizontal surface and place your compass on the map. Using the edge of the compass as a ruler, place it so that it creates a line between your current position and where you intend to go.
- Rotate the degree dial until the orienting arrow points to true north on the map. This will also align the compass’s orienting lines with the map’s north-south lines. Once the degree dial is in place, put the map away.
- In this case, you'll correct for declination by adding the appropriate number of degrees in areas with West declination, and subtracting in areas with East declination. This is the opposite of what you'll do when first taking your bearing from the compass, making this an important distinction.
Use the new bearing to navigate.
Hold the compass horizontally in front of you with the direction of travel arrow pointing away from you. Use this arrow to guide you to your destination. Turn your body until the north end of the magnetic needle is aligned with the orienting needle, and you'll be properly oriented toward the destination on the map. In the next post I will be showing you how to use your map and compass to find your position if you do lose track of where you are.
FINDING YOUR POSITION WHEN LOST
One of the most difficult things you can do with your map and compass is finding your location when you get lost or take a wrong turn. This can be a life saving exercise if you do find yourself in trouble. It will locate your position on the map and in turn will give you a grid reference for you to pass on to either the emergency services or other people that might be able to help you (if you have been in a group and got separated)
- FIND AT LEAST THREE DISTINCTIVE LANDMARKS THAT YOU CAN SEE AND LOCATE THEM ON YOUR MAP ideally these should be spread around, not just in front of you. The more landmarks you can locate the more accurate your reading will be.
- POINT THE DIRECTION OF TRAVEL ARROW AT THE FIRST LANDMARK the compass needle will spin off to one side (unless the landmark is North of you), turn the compass dial until the orienteering arrow and the compass needle line up. Correct for declination. This will then tell you the direction of the landmark (or the bearing of that landmark.)
- PUT THE DIRECTION OF THE LANDMARK ON YOUR MAP by placing your map on flat surface and then placing your compass on to the map with the orienteering arrow pointing North. Then move your compass around so that one of the edges of your compass passes through the landmark, taking care not to move the dial and keeping the orienteering arrow pointing North. Draw a line along the edge of the compass.
- YOUR POSITION is now somewhere along this line. This is the first of three lines you will draw on the map.
- REPEAT THE PROCESS with the other 2 landmarks. You will now notice that, near where your three lines cross you will have formed a triangle. Your position is somewhere within this triangle. The more accurate you are when taking the bearings of the landmarks and with the declination, the smaller the triangle will be. With practice you can near enough pinpoint your position on the map. This is called triangulation. (this is basically also how radar works)
- It's often easier to use features in your immediate vicinity to locate your precise position.
- Triangulation is more useful if you're really lost or you are in a barren, featureless area.
- Trust your compass: 99.9% of the time it is giving you the correct direction. Many landscapes look similar, so again, TRUST YOUR COMPASS.
- For maximum accuracy, hold the compass up to your eye and look down the direction of travel arrow to find landmarks, guide points, etc.
- The compass's tips are usually marked with either red or black tips. The northern tip is usually marked with an N, but if for some reason it isn't, try to figure out which one is north by orienting your compass to the north or south in relation to the sun. So in the Northern hemisphere the sun rises in the East and sets in the West, which means the sun will never be in the North. At midday the sun is directly South.