what is it called when you use a compass

What does the word compass mean?

compass noun. A magnetic or electronic device used to determine the cardinal directions (usually magnetic or true north). Etymology: For noun: from compas, from compas, from compassus, from com- + passus; see pass, pace. compass noun. A pair of compasses (a device used to draw an arc or circle).

What is the compass used for?

The compass is used for navigation, location and direction. People use it to find their way, whether it is on a hiking trail or on a trip to a new location. It is an instrument composed of a suspended magnetic pointer that is attracted to the polarity of the North Pole.

What is the definition of compass?

com•pass (ˈkʌm pəs) n. 1. an instrument for determining directions, as by means of a freely rotating magnetized needle that indicates magnetic north. 2. Often, compasses. an instrument for drawing or describing circles, measuring distances, etc., consisting generally of two hinged, movable legs (often used with pair of ).

What is the definition of compass in math?

compass. 2. (Mathematics) ( often plural) Also called: pair of compasses an instrument used for drawing circles, measuring distances, etc, that consists of two arms, joined at one end, one arm of which serves as a pivot or stationary reference point, while the other is extended or describes a circle.

What is a compass?

A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north.

What is the most common type of compass?

Magnetic compass . The magnetic compass is the most familiar compass type. It functions as a pointer to " magnetic north ", the local magnetic meridian, because the magnetized needle at its heart aligns itself with the horizontal component of the Earth's magnetic field.

Why is a compass subject to errors?

A compass is also subject to errors when the compass is accelerated or decelerated in an airplane or automobile. Depending on which of the Earth's hemispheres the compass is located and if the force is acceleration or deceleration the compass will increase or decrease the indicated heading. Compasses that include compensating magnets are especially prone to these errors, since accelerations tilt the needle, bringing it closer or further from the magnets.

How reliable is a magnetic compass?

The magnetic compass is very reliable at moderate latitudes , but in geographic regions near the Earth's magnetic poles it becomes unusable. As the compass is moved closer to one of the magnetic poles, the magnetic declination, the difference between the direction to geographical north and magnetic north, becomes greater and greater. At some point close to the magnetic pole the compass will not indicate any particular direction but will begin to drift. Also, the needle starts to point up or down when getting closer to the poles, because of the so-called magnetic inclination. Cheap compasses with bad bearings may get stuck because of this and therefore indicate a wrong direction.

What degrees does a compass show?

Compasses often show angles in degrees: north corresponds to 0°, and the angles increase clockwise, so east is 90°, south is 180°, and west is 270°. These numbers allow the compass to show azimuths or bearings which are commonly stated in degrees. If local variation between magnetic north and true north is known, then direction of magnetic north also gives direction of true north.

Why is the local magnetic declination given on most maps?

The local magnetic declination is given on most maps, to allow the map to be oriented with a compass parallel to true north. The locations of the Earth's magnetic poles slowly change with time, which is referred to as geomagnetic secular variation.

Why does a compass needle turn?

When the compass is held level, the needle turns until, after a few seconds to allow oscillations to die out, it settles into its equilibrium orientation.

What is the most common type of compass?

The most popular type of compass is the magnetic compass, relying on a magnetized needle that aligns itself with Earth’s magnetic field.

What are the parts of a compass?

Parts of a Compass. The baseplate is made usually of plastic and it’s the small plate the actual compass actually sits on. Depending on the type of compass, it has rulers and scales to help you measure distance on a map. Before buying a compass, check the common scales of maps in your area and make sure the scales of the maps and the compass match; ...

How to find direction of a compass?

In order to find it, turn the degree dial surrounding the compass housing until the orienting arrow is completely lined up with the magnetic needle. In this position, the direction arrow on the baseplate of the compass will indicate your heading.

How to read a magnetic compass?

Put the compass on your palm, keeping the elbow at 90 degrees at the chest level. The magnetic needle shouldn’t touch the top or the bottom of the compass housing. Keep your hand as steady as possible and watch the magnetic needle: the North is where its red tip is pointing.

What is the compass rose?

This means that the tip of the needle will always point to the North, while its opposite side will be oriented toward South. The compass also has a diagram on it , called a compass rose, where the cardinal points are marked with initials: N, S, E and W.

Where is the orienting arrow on a compass?

The end that points toward North is usually painted red, and the other end, pointing South, is often white or black; The orienting arrow is located within the compass housing .

How to determine direction of a landmark?

To determine the direction, or the bearing, of that specific landmark, you have to turn toward it and repeat the process used to determine your heading. Once you have the bearing, you can start walking toward it, even if the surrounding terrain sometimes obscures the landmark. Just take new readings from time to time, to make sure you are staying on track.

What is a compass?

A compass is one of the most basic navigation tools any hiker can own. It needs no batteries, works with any map, and even works without a map! While entire books have been written about navigating with a compass, every new compass user needs to know the basic concepts.

How to use a magnetic needle on a compass?

By sight, it’s much simpler. If you are heading to a mountain for example, point at it from your current position with the travel arrow on the compass. Then rotate your azimuth ring until the orienting arrow is lined up with the red end of the magnetic needle pointing towards north. Continue on your path so that the needle and its housing remain intact and you should have no problem reaching your destination.

How to align a compass arrow?

Line up the edge of your compass on this line so that the travel arrow is in the direction you wish to travel, then twist the azimuth ring (which is simply the ring with the measured units of degrees on a compass) until north on the map and the orienting arrow are aligned.

What is the difference between magnetic north and true north?

In most locations in the real world, though, magnetic north (where your needle points) and true north differ by a few degrees: That difference is known as “declination.”. In the continental U.S., declinations vary from 20 degrees east in parts of Washington state to 20 degrees west in parts of Maine.

What is baseplate clear?

Baseplate: Clear, so you can see the map below it, it has at least one straight edge for taking bearings and transferring them to your map.

What is a parallel line that rotates with the bezel?

Orienting lines: Parallel lines that rotate with the bezel; correctly aligning these with the north-south lines on a map aligns your orienting arrow with north.

What is a direction of travel arrow?

Direction-of-travel arrow: Tells you which direction to point the compass when you’re taking or following a bearing.

Can you use a bearing to find where you are on a map?

You can also use a bearing to find where you are on a map. You might want to know exactly where you are along a trail.

What is a compass used for?

It’s probably time to change that, isn’t it? Essentially a compass is nothing more than a magnetized needle, floating in a liquid, and responding to the Earth’s magnetic field consequently revealing directions. Over time compass markers have added features which make compasses work more harmoniously with maps and also more beneficially as stand alone tools. Today, compasses can be classified as one of four types, namely: fixed-dial (the type that you find on a key chain, or that come out of a gum ball machine), floating dial (the needle is an integrated part of the degree dial), cruiser (professional grade instrument used by foresters), and orienteering. For hiking, mountaineering, back country skiing , canoeing, hunting or the like, the orienteering type is the most sensible being accurate to within 2 degrees, not requiring a separate protractor nor map orientation, and being highly affordable. Hence forth, this article focuses solely on the orienteering compass.

What are the different types of compasses?

Today, compasses can be classified as one of four types, namely: fixed-dial (the type that you find on a key chain, or that come out of a gum ball machine), floating dial (the needle is an integrated part of the degree dial), cruiser (professional grade instrument used by foresters), and orienteering.

How to use a compass to follow a bearing?

A bearing is the direction from one spot to another, measured in degrees, from the reference line of north; in other words it’s one of the 360 degrees of the compass rose. To take a bearing hold the compass in front of you with the direction of travel arrow pointing at the object of interest. Hold the compass level and steady, and rotate the housing dial, until the orienting arrow lines up with the red end (north end) of the magnetic needle, all the while keeping the direction of travel arrow pointed at the object. Read the number indicated at the index line, and that is your bearing. Now to follow that bearing to the object, let’s consider an example. Say you want to travel to a large rock outcropping on the horizon, which is currently visible to you, but which may leave your field of vision when you walk into a dip, or when pending clouds come in or the sun sets. Let’s say your bearing on the outcropping measured 315 degrees (or NW). Assuming you still have the direction of travel arrow pointing at the rock outcropping, and have not changed the 315 degree bearing setting on the dial, walk forward keeping the magnetic needle over the orienting arrow (by rotating your body, and not the dial), and the straight line course (as pointed out by the direction of travel arrow), will lead you to the rock outcropping. En route, when the rock outcropping leaves you line of sight pick out an intermediate landmark along the bearing, so you don’t have to constantly look down at your compass. Walk to the intermediate landmark, and repeat with another landmark until you reach your destination. Once you arrive at the rock outcropping, what bearing do you use to return to where you came from? Actually you don’t need any other bearing besides the 315 degrees already set on your compass. To return, just point the direction of travel arrow at you, instead of forward, and then rotate your body until the orienting arrow lines up with the red end (north end) of the magnetic needle, and then walk straight ahead while keeping the magnetic needle over the orienteering arrow (just as you did in going to the rock outcropping). That is the easy way to backtrack, of course you could also calculate your back bearing by subtracting 180 from your forward bearing of 315, and set the 135 degree (SE) difference at the compasses index line and then use the same body rotating method mention earlier, only this time you’d have the direction of travel arrow pointing your way. Try this. Take your compass to an empty parking lot or field and mark a spot. While standing at the spot set your compass to any bearing between 0 and 120 degrees, pick a landmark along the direction of travel and take 15 steps toward it. Stop, add 120 degrees to your initial bearing, pick out a landmark along that bearing and walk another 15 steps toward it, stop and once again increase your bearing by 120, pick out a third landmark and again walk 15 steps. Notice you have arrived back at your original starting location. Let’s return to the example above where we took a 315 degree (or NW) bearing on a rock outcropping, and lets suppose that enroute to the outcropping we encounter an obstacle which we must go around thus forcing us to deviate from our straight line course. If you are lucky enough to be able to pick out a landmark that’s along the bearing, and also on the other side of the obstacle, you have nothing to worry about, just go around the obstacle and get back on course by reaching the landmark and aligning the red end of the magnetic needle over the orienteering arrow, and continue walking.

What are the parts of an orienteering compass?

As figure 1 shows an orienteering compass typically consists of three main parts: a magnetic needle, a revolving compass housing, and a transparent base plate. The magnetic needles north end is painted red and its south end white.

Where does the magnetic needle point on the agonic line?

In areas to the left of the agonic line the magnetic compass needle points a certain number of degrees to the east of true north, and on the other side of the line the magnetic needle points a certain number of degrees to the west of true north (in other words the magnetic needle points toward the agonic line).

What constellation is the Big Dipper in?

In the Northern Sky the Big Dipper is one of the most familiar asterisms of the constellation Ursa Major (the Great Bear). As the Earth moves around the sun the angle of our view of the Big Dipper changes and thus is different for each season.

What is an altimeter?

Altimeter: An altimeter can be a useful companion to your topographic map and compass, assuming one knows how to calibrate it.

What is a 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.

How to read a compass?

2. Hold the compass correctly. Place the compass flat on your palm and your palm in front of your chest. This is the proper compass stance, when traveling. If you're consulting a map, place the map on a flat surface and place the compass on the map to get a more accurate reading. 3.

How to use a compass to guide you to a destination?

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.

How to use a compass as a ruler?

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.

What is the arrow on a compass?

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.

What is a compass baseplate?

While the designs of compasses are different, all compasses include a magnetized needle that orients itself to the magnetic fields in the Earth. The basic field compass, also sometimes called a baseplate compass, features the following simple components you should familiarize yourself with as soon as possible:

What direction does a compass point?

The compass needle will point toward magnetic north (assuming you are holding the compass flat as described, and not near large metal objects). Therefore, if you travel in the direction of the needle, you will be going north. That is probably not what you want. If you have set up your compass correctly according to this wiki, you want to travel in the direction of the "direction of travel" arrow, which is the large arrow on the compass base. If traveling straight is not possible (due to terrain and/or obstacles), sight a near landmark in that direction and make your way to it. Once there, repeat the process.

Overview

Modern compasses

Magnetic compass

Non-magnetic compasses

History

Construction of a magnetic compass

Using a magnetic compass

See also