What Is a Digital Compass?

In some ways, a digital compass is like its analog counterpart. Both compasses use the Earth’s magnetic field to determine which way is North, and both help bikers, hikers, mapmakers and trail makers know which direction they are heading. The difference is that an analog compass can wobble because of movement and may encounter interference from strong magnetic sources, so inaccuracy is a problem. A digital compass is much more accurate and sturdy, because it will only use the North Pole as a guiding mechanism. Aside from serious hikers and trail makers, the military also uses these compasses for the best accuracy.

The compass, whether traditional or digital, is made to help users know which direction they are heading. Both are supposed to use the Earth’s magnetic field to determine which way is North, and all other directions are based off that. With a traditional compass, while it can be accurate, there are many problems with its operation. If there are magnetic metal deposits nearby, or just a powerful magnetic field, the compass will consider the deposit to be North or will spin aimlessly. The needle on a compass also can wobble, which may cause it to show the wrong direction.


A digital compass overcomes these problems. Instead of a shaky needle, this type of compass has a digital screen that presents the four primary directions and plainly tells the user which way he or she is facing. The screen is easier to see than an analog compass needle, and the compass itself is far more accurate.

Instead of determining direction based on magnetic pulses, which can be inaccurate or random, a digital compass determines direction by using the North Pole as a guide. For this end, the compass usually has some global positioning system (GPS) features, which may or may not be available to the user. Along with this feature, most digital compasses come with extra features, such as a thermometer, and can be used to tell directions on foot, on water or in the air.

Digital compasses are used by many different people and industries, mostly because of the accuracy a digital compass has over a traditional model. Airlines use these compasses to ensure that their planes are flying in the right direction, and cars that have compasses usually contain digital ones. The military also use digital compasses to ensure there is never any inaccuracy during combat or other situations.

What Is a Fluxgate Compass?

A compass is a device used to ascertain directional orientation. The most common type of compass is a simple magnetic compass that utilizes the magnetic pull of Earth's North Pole to determine which direction is north. A fluxgate compass, on the other hand, is a more sophisticated, electronic version of the magnetic compass that requires electricity to operate. A fluxgate compass may be used on a on a boat, aircraft, or any other vehicle that requires a navigational system. The electronic output of the fluxgate compass allows it to be used in more ways than the traditional magnetic compass.

The most obvious use of the fluxgate compass is for steering. When used in this manner, a digital display alerts a pilot or driver to changes in direction so that he or she is able to make adjustments and remain on the proper course. Others connect the compass to autopilot equipment. When an autopilot system is in use, the fluxgate compass sends a digital signal to the autopilot, which then prompts the machinery to make steering adjustments. The digital signal generated by the fluxgate compass can also be used in conjunction with other navigational tools such as chart plotters and radar.


Like the traditional magnetic compass, the fluxgate compass determines direction by assessing Earth's magnetic fields. However, rather than relying on one small magnet, fluxgate compasses are typically made with coils of wire that employ electricity to amplify the directional signal. Unlike the traditional magnetic compass which relies on a moving needle that is placed atop the magnet, the fluxgate has no moving parts. Rather than pointing towards the North Pole, the fluxgate compass measures electric current, and it is this current that is used as a signal that can be translated and by other electronic devices.

The fluxgate compass has both advantages and disadvantages. The most obvious disadvantage is its need for electricity. Most users keep a traditional magnetic compass on hand as backup for situations that cause a loss of electricity. They are also less stable and have more chance of malfunction due to faulty electronic components. Most navigators consider the advantages, such as the ability to connect to other navigational equipment, worth these risks. One other advantage over a traditional compass is that the fluxgate can be placed in remote locations. This is a major plus because the magnetic influence of other equipment can erroneously alter the reading of either type of compass.

What are the Different Types of Compass?

A compass is a device which can determine a direction on the Earth, usually used for navigation. A compass may be aligned to either magnetic north or true North, or occasionally to an arbitrary direction based on the location of celestial bodies. Magnetic north is the direction of the north tip of the Earth's magnetic field, while true North is the direction in which the Earth rotates.

The most common type of compass is a magnetic compass, which is used to ascertain the direction of magnetic north. A magnetic compass is made by placing a bit of magnetized iron or steel in a setting of low friction so that it is allowed to move about freely. In most compasses, the north-end of the metal piece is marked, most often with red paint, so that all directions may be ascertained.

The use of the magnetic compass can be traced back as far as 4th century BC China, where a type of magnetite known as lodestone was used as a tool in a type of divining magic known as geomancy. The Chinese mastered the use of magnetic iron for navigation by the beginning of the 12th century, and its use quickly spread to Europe and beyond. By the beginning of the 13th century, Arabs were using the magnetic compass in navigation, and by the beginning of the 14th century, an Italian had created what would be recognizable to modern eyes as a mariner's compass.


A gyrocompass is a special type of compass developed in the late 19th century, which ascertains true North, rather than the somewhat more fickle magnetic north. A gyrocompass is essentially a very fast spinning wheel or ball, which utilizes the law of conservation of angular momentum and the spinning of the Earth's axis to point towards true North. The gyrocompass is commonly used on large ships, and in other situations where a more accurate reading of north is required.

An astrocompass is another type of compass which can find true North rather than magnetic north. An astrocompass relies on the position of celestial bodies to find true North, which is useful in a number of situations, particularly at the far north and south poles, where magnetic compasses become unreliable and gyrocompasses often cease working. One requires a fair amount of information to utilize an astrocompass properly, including the time, date, and longitudinal and latitudinal location, as well as an astronomical chart such as a nautical almanac. Given this information, a person may fix upon a known star and determine the exact direction of true north.

In the digital era, solid state compasses are becoming increasingly common as well. These use a number of electronic magnetic sensors which calculate the precise direction the compass is pointing.

GPS compasses are quickly replacing many traditional compasses for personal use, though most ships and military operations have a gyrocompass or magnetic compass on hand in case a GPS cannot pick up enough satellites. GPS compasses make use of satellites in a geo-synchronous orbit over the Earth to discern the bearer's exact location and the direction they are heading. Because of the ease of use and relative reliability of the GPS compass, many hikers and drivers favor it. As with all electronics, however, the GPS compass is susceptible to a number of problems, and it is recommended that most hikers have a backup form of navigation available as well.

What Is an Azimuth Compass?

An azimuth compass is a compass that displays direction or bearing markings in terms of azimuth angles rather than any other form of bearing notation. There are two principal systems used to display direction markings on the face of a compass: quadrant bearings and azimuth bearings. Both systems provide exactly the same directional information but in a different format. People who have used a compass have most likely used an azimuth compass.

The quadrant bearings system marks both the North and South positions as zero degrees. Direction is then measured in degrees using both North and South as the base reference points. For example, starting at North and moving clockwise 35° results in a quadrant bearing N35°E. Alternatively, starting at East and moving counterclockwise 55° results in the same bearing N35°E. In this system, North or South will always be the first notation in the bearing.

The most widely used compass markings are those of the azimuth bearings system. In this system, the only position marked as zero is North. Moving clockwise, degrees are added through the full 360° of a complete circle. In this system, East is marked as 90°, South as 180°, and West as 270°.

The following table further clarifies the two systems. The table provides eight separate direction headings each expressed first as a quadrant bearing and then as an azimuth bearing.


Azimuth bearings are based on the concept of an azimuth angle, also referred to simply as an azimuth. An azimuth is defined, from any given observation point, as the angle between an object or point and a reference line, usually to true North, moving away from that reference line in a clockwise direction on a horizontal plane. For example, standing on a ship with the ocean as the horizontal reference plane, the angle between true North and, say, a lighthouse is the azimuth for that lighthouse relative to the ship, that angle being measured by moving clockwise away from the line to true North.

Similarly, if that ship is traveling along a bearing S10°W, the navigator on that ship imagines a line drawn along that bearing intersecting with a line drawn from the ship to true north. The 190° angle formed by those two lines is the azimuth that defines the direction in which the ship is traveling relative to true north. An azimuth compass on that ship would indicate a bearing of 190°.

The largest azimuth angle that may ever be measured is 359 degrees 59 minutes 59 seconds, often written as 359° 59' 59", this being slightly less than the 360° defined by a full circle. Technically, based on the azimuth bearings system, it is incorrect for any point on the compass to be marked as both 0° and 360°. This is why an azimuth compass, by convention, marks N as 0°.

The concept of an azimuth angle is used frequently in a wide range of practical applications. These include land navigation, celestial navigation, mapping and artillery. The key feature distinguishing an azimuth compass from any other compass is the direction markings shown on the face of the compass rather than any difference in the technical workings of the compass.

What Is a Compass Saw?

A compass saw is a small hand or power saw featuring a narrow tapered blade used for cutting curves and inside profiles in timber paneling, PVC, and drywall sheets. These devices are also handy for use in small confined spaces where larger saws are impractical. Compass saws feature fixed or retractable blades which are typically interchangeable. This allows for the replacement of blunt blades and several blade lengths and tooth pitches to be used with one handle. Compass saws are similar to keyhole saws except they are slightly larger with typical blade lengths running between 5 and 15 inches (127 and 381 mm).

Compass saws are typically used to cut awkward shaped holes from the inner surfaces of a variety of common construction materials. They are also often used to cut PVC tubing or timber in small, cramped spaces. The compass saw may be used to cut most plastics, non-ferrous metals, soft timber panels, pressed wood, and drywall sheeting. Their narrow tapered blades allow easy cutting of circular holes and small radius curves. These saws are generally hand operated although electrical reciprocating compass saws are available.


The blade of a compass saw is either of a fixed or retractable design. They are typically interchangeable allowing for easy replacement of blunt or broken blades. This also allows a range of blade lengths and tooth pitches to be used with one handle catering for cuts in a selection of materials. The most popular blade lengths are 10 to 12 inches (254-304 mm) although different lengths are also commonly used for specific applications. Short blades, for example, allow the saws to be used to cut out shapes from one side of a drywall without penetrating the opposite sheet.

When cutting holes in soft materials such as dry walling, the narrow pointed blade allows the initial penetration to be achieved without having to pre-drill pilot holes. The ability to retract the blade to an optimal length on some saws also prevents undesirable blade flex and blade breakage when cutting harder materials. Most compass saw blades have teeth which only cut on the pull stroke, thereby helping to prevent the blades binding while cutting. This feature also ensures clean cuts even when working in confined spaces.

As with most saw designs, the compass saw blade should be matched to the material being cut. The general rule is the denser and harder the material, the finer the tooth pitch should be. A general purpose blade will feature a tooth pitch of between 8 to 10 teeth per inch (25.4 mm). A blade designed for harder timber and aluminum may feature tooth densities of up to 20 teeth per inch. Compass saw blades used for softer fiber boards or dry walling my have as few as five teeth per inch.

What Is a Liquid Compass?

A liquid compass is a compass which is filled with fluid. The fluid acts as a buffer, absorbing shock and vibrations to avoid damage to the elements in the liquid compass, and it also helps to stabilize the compass needle to make the device easier to read. Many compasses are liquid filled, and they come in a variety of styles ranging from ball compasses to small models which are designed to clip onto a keychain so that they are available for easy reference.

The concept of the liquid compass was introduced as early as the 1600s, but did not catch on until the 1900s, when they were adopted as standard navigational instruments by several navies. The compass includes a needle which is sensitized so that it will always point towards Earth's magnetic north, with a backing which is marked with degrees so that users can determine which direction they are facing on the basis of the marking the needle lands on. Using a liquid compass, people can determine which direction they are heading in, and use this information in navigation.


The viscosity of the fluid can depend on the design; alcohol, oil, and kerosene are three common choices for fluid, and it may be dyed to increase visibility. The compass is designed to allow the liquid to expand and contract slightly without breakage. One advantage to using a liquid compass is that the needle stabilizes very quickly and prevents wobbling, allowing people to take accurate measurements more easily. Another is that the device tends to be more tolerant of shaking, dropping, and other forms of abuse.

Numerous companies make liquid compasses of all shapes and sizes. The liquid damped compass continues to be a handy basic navigation tool, although it has been largely supplanted by things like GPS devices. A compass will still work when GPS is broken or unavailable, however, and many people learn the basics of compass navigation as part of their training for hiking, boating, and other outdoor activities, during which being able to navigate can be very important.

One important thing to be aware of when someone uses a compass is that the device points towards magnetic north, not true north. Magnetic north actually wobbles around the geographic north, making it necessary to adjust for declination, the variance between magnetic and true north. Many compasses allow users to adjust for this, and declination information is usually published on maps and charts.

What Is a Compass Inclinometer?

The inclinometer on a compass can provide the height, in degrees above the horizon line, of any object. Many measurements such as this can be taken with a compass inclinometer to develop a basic topological survey map, to measure range of motion in the joints of a body, or to determine the “look angle” of a satellite antenna toward a satellite. Compass inclinometers measure in degrees rather than percentages, but they come with a conversion tool that converts to percentages for use in individual construction projects when necessary to measure a slope or if you need to measure an angle not easily measured in any other manner. A compass inclinometer can also be used with a tape measure to take readings to produce cave maps below ground, something cave scientists and speleologists do on a regular basis. When above ground, graph paper and a protractor can help produce the cave map from these readings.


An inclinometer is also sometimes called a tilt sensor, as it can measure angular tilt by producing a false horizon. This tilt sensor capability is the same as those in use in flight control systems, auto security systems, and cameras. This same technology is also found in game controllers for popular video game modules and is often used by civil engineers to measure an incline on land that will become a construction site. Calculating the deviation from true vertical or true horizontal or determining latitude using the northern hemisphere’s “Polaris” and the southern hemisphere’s “Crux” is another function on a compass inclinometer.

A compass inclinometer works on the geometry of triangles; some use measurements and others employ percentages and degrees. When looking through the lens of a compass inclinometer, three things are visible: a protractor, a weighted line, and a viewing scope. A person looking through the lens will notice that the weighted line changes place along the protractor as he or she turns his or her head. Standing very still, a person can take the measurements that, when entered into algebraic equations, determine the angle by triangulation. These measurements are the viewer’s distance in feet from the object he or she is viewing, and the height of his or her eyes — generally, 6 inches (15.25 cm) from his or her height.

To calculate from a specific distance, an inclinometers must be calibrated accurately. Users may need to consult their manuals to recalibrate inclinometers. Once calibrated, a compass inclinometer can help safely map hiking trails and measure steep inclines and declines such as ravines, cliff faces, and cracks in a mountainside snow pack.