I know where I am, but I don't know which way to hike. I am hiking toward a visible mountain, but it is getting dark and I'm afraid I'll lose sight of the mountain. How do I make sure I get there? What do I do when I am really lost?3 main ways to use your compass.
What is declination?
- Obtaining a travel direction from a map: Use the known starting and ending points from your map and align your compass with them so that you may travel along that line without constantly looking at your map.
- Place the compass on the map so the long edge of the base plate connects the starting point with the desired destination or end point. Make sure that the direction arrows are pointing from the starting point to your destination (and not the other way).
- Hold the compass firm on the map in order to keep the base plate steady
- Turn the capsule until the N-S lines on the bottom of the capsule are parallel with the N-S (magnetic meridian) lines on your map. Make sure the N-S arrow on the bottom of the capsule points to the same direction that is marked with "N" at the top of the N-S lines on the map.
- Next, hold the compass in front of you making sure that the base plate is in a horizontal position and the direction arrows are pointing straight ahead.
- Rotate your body until the N-S arrow on the bottom of the capsule lines up directly under the magnetic needle, and the red end of the needle points in the same direction as the arrow.
- You can now read your direction of travel along the direction arrows on the base plate.
- Taking a bearing on a visible landmark: If you are traveling toward a visible object in the landscape (distant hill or mountain peak), you may need to set your compass to point the direction to this landmark in case it is not visible at all times do to darkness, weather or tree cover.
- Sight the landmark along the direction arrows on the base plate. Hold the compass in a horizontal position.
- Keeping the object in line with the direction arrows, turn the capsule until the red end of the magnetic needle in pointing in the same direction as the N-S arrow on the bottom of the capsule. The bearing is now set on your compass.
- Start hiking, and when you check your direction of travel make sure that the N-S arrow is lined up directly under the needle.
NOTE: Using a mirrored compass will make it much easier to sight in your bearing and see the N-S arrow at the same time.
- Triangulation: Use this method when you are really lost and have a map and visible landmarks. This is combination of the later two processes and will allow you to find your location on land or sea. You will need a pencil.
- Find a spot where 2 distinct objects can be found in the landscape and on the map. Determine the bearing of the first landmark and place the compass on the map so that the long edge touches the landmark on the map.
- Keeping the object steady on the edge of the compass, pivot the whole compass around the object until the N-S lines on the bottom of the capsule are parallel with the N-S (magnetic meridian) lines on the map. Check that the N-S arrow is pointing towards the N at the top of the N-S lines on the map. Be careful not to turn the capsule as you pivot the compass.
- When your compass is in the right position, hold the compass base firmly on the map and draw a line along the compass edge so that the object is on that line. Repeat the process with another landmark. Your position will be where these two line intersect, if possible use a third object to check the result.
Declination is the angle difference between true (geographical) north and magnetic north. A compass needle points to magnetic north, which is separated from true north by over 1,000-mile distance at the North Pole. The declination is said to be either easterly or westerly depending on your location to true north.
For example, if you live in the state of Washington, your declination will be about 20 degrees to the east because you are west of true north. If you are in Florida, your approximate declination is 3 degrees to the west. The zero (0) declination line in the US runs from the West Coast of Florida up to eastern Minnesota at the Canadian Border.
Declination is usually displayed on topographical maps in one of the bottom corners. Once you found this angle for your area you can lock into your compass and receive accurate bearing readings.How do I learn how to use my compass before heading out into the wilderness?
The best way to learn how to use a compass is to read up on the subject and then head out to your local, well-known wilderness area, a place were you know you won't get lost, and practice.
The instructions that typically come with a compass are good, but lack the explanation of why you are doing something. Some compasses come with "built in instructions;" this is a great idea and comes in handy in the field. If you are very serious about learning how to use a compass, consider clubs or classes that are offered by various outdoor groups. You may also want to purchase one of the many good books on how to use a map and compass.