Difference between revisions of "Use a Compass"
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A compass is an essential tool in wilderness survival. Along with a good quality topographical map of the area you're navigating, knowing how to use a compass will ensure that you're never lost. You can learn to identify the basic components of the compass, take an accurate reading of your bearings, and start developing the necessary skills of navigation with a few simple steps. See Step 1 to start learning to use your compass. | A compass is an essential tool in wilderness survival. Along with a good quality topographical map of the area you're navigating, knowing how to use a compass will ensure that you're never lost. You can learn to identify the basic components of the compass, take an accurate reading of your bearings, and start developing the necessary skills of navigation with a few simple steps. See Step 1 to start learning to use your compass. | ||
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== Steps == | == Steps == | ||
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#*'''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. | #*'''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. | #*'''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. | ||
| − | #Understand the difference between "true" North and "magnetic" North. While it might seem confusing that there are two kinds of "North," it's a basic distinction that you can learn quickly, and it's an essential piece of information to learn to use a compass properly.<ref>http://www.princeton.edu/~oa/manual/mapcompass2.shtml#Compass</ref> | + | #Understand the difference between "true" North and "magnetic" North. While it might seem confusing that there are two kinds of "North," it's a basic distinction that you can learn quickly, and it's an essential piece of information to learn to use a compass properly.<ref name="rf16307">http://www.princeton.edu/~oa/manual/mapcompass2.shtml#Compass</ref> |
#*'''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. | #*'''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. | #*'''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. | ||
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#Transpose the direction of travel onto your map.<span id="draw"></span> 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. | #Transpose the direction of travel onto your map.<span id="draw"></span> 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. | #*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. | ||
| − | #Learn to take a bearing from the 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.<ref>http://www.rei.com/learn/expert-advice/navigation-basics.html</ref> | + | #Learn to take a bearing from the 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.<ref name="rf16308">http://www.rei.com/learn/expert-advice/navigation-basics.html</ref> |
#*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. | #*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. | #*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. | ||
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#Aim the direction of travel arrow at the first landmark. Unless the landmark is north of you, the magnetic needle will spin off to one side. Twist the degree dial until the orienting arrow lines up with the north end of the magnetic needle. Once they are aligned, this will tell you where your direction of travel arrow is pointing. Correct for declination, depending on your area. | #Aim the direction of travel arrow at the first landmark. Unless the landmark is north of you, the magnetic needle will spin off to one side. Twist the degree dial until the orienting arrow lines up with the north end of the magnetic needle. Once they are aligned, this will tell you where your direction of travel arrow is pointing. Correct for declination, depending on your area. | ||
#Transpose the direction of the landmark onto your map. Place your map on a horizontal surface and then place the compass on the map so that the orienting arrow points to true north on the map. Then, slide your compass around so that its edge passes through the landmark on the map, while the orienting arrow continues to point north. | #Transpose the direction of the landmark onto your map. Place your map on a horizontal surface and then place the compass on the map so that the orienting arrow points to true north on the map. Then, slide your compass around so that its edge passes through the landmark on the map, while the orienting arrow continues to point north. | ||
| − | #Triangulate your position. Draw a line along the compass' edge and through your approximate position. This is the first of three lines you will draw to find your position by forming a triangle with the other two landmarks.<ref>http://www.princeton.edu/~oa/manual/mapcompass3.shtml#Scenarios</ref> | + | #Triangulate your position. Draw a line along the compass' edge and through your approximate position. This is the first of three lines you will draw to find your position by forming a triangle with the other two landmarks.<ref name="rf16309">http://www.princeton.edu/~oa/manual/mapcompass3.shtml#Scenarios</ref> |
#*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. | #*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. | ||
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== Tips == | == Tips == | ||
