The baseplate is the clear, plastic plate on which the compass is embedded. The direction of travel arrow is the arrow in the baseplate pointing away from the compass. The compass housing is the clear, plastic circle that houses the magnetized compass needle. The degree dial is the twistable dial surrounding the compass housing that displays all 360 degrees of the circle. The magnetic needle is the needle spinning within the compass housing. The orienting arrow is the non-magnetic arrow within the compass housing. The orienting lines are the lines within the compass housing that run parallel to the orienting arrow.
Turn the degree dial until the orienting arrow lines up with the magnetic arrow, pointing them both North, and then find the general direction you’re facing by looking at the direction of travel arrow. If the direction of travel arrow is now between the N and the E, say, you’re facing Northeast. Find where the direction of travel arrow intersects with the degree dial. To take a more accurate reading, look closely at the degree markers on the compass. If it intersects at 23, you’re facing 23 degrees Northeast.
True North or Map North refers to the point at which all longitudinal lines meet on the map, at the North Pole. All maps are laid out the same, with True North at the top of the map. Unfortunately, because of slight variations in the magnetic field, your compass won’t point to True North, it’ll point to Magnetic North. Magnetic North refers to the tilt of the magnetic field, about eleven degrees from the tilt of the Earth’s axis, making the difference between True North and Magnetic North different by as many as 20 degrees in some places. Depending where you are on the surface of the Earth, you’ll have to account for the Magnetic shift to get an accurate reading. While the difference may seem incidental, traveling just one degree off for the distance of a mile will have you about 100 feet (30. 5 m) off track. Think of how off you’ll be after ten or twenty miles. It’s important to compensate by taking the declination into account.
In the US, the line of zero declination runs up through Alabama, Illinois, and Wisconsin,[5] X Research source at a slight diagonal. East of that line, declination orients toward the West, meaning that Magnetic North is several degrees West of True North. West of that line, the opposite is true. Find out the declination in the area in which you’ll be traveling so you can compensate for it. Say you take a bearing on your compass in an area with West declination. You’ll add the number of degrees necessary to get the correct corresponding bearing on your map. In an area with East declination, you’ll subtract.
Twist the degree dial until the orienting arrow lines up with the north end of the magnetic needle. Once they’re aligned, this will tell you where your direction of travel arrow is pointing. [6] X Research source Take off local magnetic variation by twisting the degree dial the correct number of degrees to the left or right, depending on the declination. See where the direction of travel arrow lines up with the degree dial.
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.
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.
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.
Repeat this process for the other two landmarks. When you’re done, you will have three lines that form a triangle on your map. Your position is inside this triangle, the size of which depends on the accuracy of your bearings. More accurate bearings reduce the size of the triangle and, with lots of practice, you may get the lines to intersect at one point.
