Using a compass
Compass Navigation & Using a Compass
Using a Hiking Map alone will often not be enough. To be sure about your location and heading, you can use a Compass or use GPS Navigation. In this section, we will look at the features of a Compass. Nowadays, most Compasses used for Hiking and Outdoor Activities look like the Compass given here. These are the basic components of a Compass:
- Compass Needle: This arrow will always point to the Magnetic North. This will be outlined later in more detail. Often the compass needle is painted red so you do not mistake the north arrow for the south arrow.
- Heading Arrow: This arrow is fixed on the base plate and it should point in the direction that you are going. So when you hold a navigation compass, always make sure this arrow is pointed towards your destination.
- Turnable Housing: This top part of the Compass holds the basic directions (north, east, south, and west) and the degrees. As we will see later on, this housing is turnable so you can adjust your bearing to the magnetic north.
- Base Plate and Grip: The base plate often has a ruler that can be used in combination with your topographical map for determining distances and triangulating your position. The end is often shaped to form a palm grip with the Heading Arrow pointing in the direction that you are going.
After getting familiar with the features, you will now learn how to use a compass. For Compass Orientation & Navigation you will need more: a topographical map, a compass, a protractor, a ruler and a pen. With these tools, you will be able to both determine your current location (Orientation) and follow a course (Navigation). Before you determine your location or follow your course, it is important to calibrate your hiking compass:
Calibrating your Compass for Magnetic Declination
Different areas on the globe have a different magnetic declination which is basically the difference between magnetic north (where your Compass will point to) and true north (the direction where north really is). There is a difference because the magnetic north pole lies about 1000 miles below the true north pole. So the declination differs per location on the globe. In general, the further north you go, the bigger the declination becomes. The magnetic declination of the area you are in can often be found on hiking maps or can be asked from local authorities. You will need to adjust your Compass to take the magnetic declination of your area into account. This is how you do this using a map:
- Get your topographical map and find the Magnetic Declination Information. Most of the time, it will give you two arrows – one signifying True North and one is for Magnetic North. Often you can also find the declination in degrees.
- Place your Compass on your map. If there are arrows then make sure to place the Heading Arrow along the True North line and turn the Compass Housing until it aligns with the Magnetic North line. Now turn your map until the Compass is pointing North along the Magnetic North line.
- Your map is now aligned to True North.
Orientation: Determining your Location on the Map
You can use your map and Compass to determine your exact location on the map by triangulating:
- Take an initial bearing on a recognizable landmark and draw a line from it through and beyond your estimated position.
- Identify a second landmark that is at least 45 degrees away from your first landmark and draw a second line.
- Your position is where both lines intersect. For a more accurate determination, use a third or even fourth landmark bearing to verify your location.
Navigation: Plot a Course using your Compass
Once you have determined your location, you can use your Compass to keep on a certain bearing:
- Place the Compass Base on your map with the Heading Arrow along the line on your map that you want to follow.
- Rotate the Compass Housing until the Compass Needle and the North Line on the Compass Housing line up.
- The Heading Arrow will now show you the correct direction and as long as you keep the Compass Needle and the North Line on the Compass Housing lined up, you will be going in the right direction.