a b Schmidl, Petra G. (2014). "Compass". In Ibrahim Kalin (ed.). The Oxford Encyclopedia of Philosophy, Science, and Technology in Islam. Oxford University Press. pp.144–146. ISBN 978-0-19-981257-8. Originally, many compasses were marked only as to the direction of magnetic north, or to the four cardinal points (north, south, east, west). Later, these were divided, in China into 24, and in Europe into 32 equally spaced points around the compass card. For a table of the thirty-two points, see compass points. Headings mid-way in-between are compounds as in English. For instance, 癸子 refers to the direction halfway between point 子 and point 癸, or 7 + 1⁄ 2°. This technique is referred to as a double-needle ( 雙針) compass. Hold the pencil in the traditional manner, but lightly, and further away from the point than usual.

The compass points can be highlighted in a rich gold colour to add further elegance or left the same colour you choose for the circle for understated beauty. Merrill, Ronald T.; McElhinny, Michael W. (1983). The Earth's magnetic field: Its history, origin and planetary perspective (2nd printinged.). San Francisco: Academic press. p. 1. ISBN 978-0-12-491242-7. a b Gade, Kenneth (2016). "The Seven Ways to Find Heading" (PDF). The Journal of Navigation. 69 (5): 955–970. doi: 10.1017/S0373463316000096. S2CID 53587934. Archived (PDF) from the original on 2022-10-09. The sixteen quarter-winds are the direction points obtained by bisecting the angles between the points on the 16-wind compass rose (above). The quarter-winds are (in first quadrant) north by east (NbE), northeast by north (NEbN), northeast by east (NEbE), and east by north (EbN); (in second quadrant) east by south (EbS), southeast by east (SEbE), southeast by south (SEbS), and south by east (SbE); (in third quadrant) south by west (SbW), southwest by south (SWbS), southwest by west (SWbW), and west by south (WbS); (in fourth quadrant) west by north (WbN), northwest by west (NWbW), northwest by north (NWbN), and north by west (NbW). [4] [5] Place the point of the pencil on the paper, lean the compass over and then smoothly turn the compass in the direction of the lean. With just a little practice, your should be able to draw a smooth, continuous circle with just one hand. It does not matter which way you turn the compass (in fact, I often turn the compass both ways for one circle), as long as you turn it in the direction you leaned - remember, draw the line.Kearny, Cresson H., Jungle Snafus... And Remedies, Oregon Institute Press (1996), ISBN 1-884067-10-7, pp. 164–170: In 1989, one U.S. Army jungle infantry instructor reported that about 20% of the issue lensatic compasses in his company used in a single jungle exercise in Panama were ruined within three weeks by rain and humidity. The “collapsing compass” is the most exact characterization of this perfect explanation instrument. It can only be used once and creates a circle with the provided radius from the supplied location. That is to say, it cannot simply be transferred to another location and utilized to create another identical circle like a real pair of compasses. Kreutz, Barbara M. (1973). "Mediterranean Contributions to the Medieval Mariner's Compass". Technology and Culture. 14 (3): 367–383. doi: 10.2307/3102323. JSTOR 3102323. S2CID 111540460. As a compass has two arms, one arm holds a pencil while the other arm has a pointed end. A compass isdesignedfor the users to grip it between their thumb and pointer finger. Keeping the same in mind, the handle length of the drawing compass is about 1.25 centimeters. The arms of the compass.The space between the compass arms is adjustable. If we keep the arms of the compass apart, it is easier to construct a circle or arc with a greater radius. There is a clamp on one end to hold a pencil whereas, on the other end, there isa sharp pointthat keeps the tool steady on the drawing surface while the pencil moves.

The four cardinal directions are north (N), east (E), south (S), west (W), at 90° angles on the compass rose. When drawing a circle using a pair of compasses, children need to place the pencil into the holder, making sure the tip of the pencil and the needle are level. They then tighten the pencil holder grip so the pencil does not move. Children then hold the top of the pair of compasses with their thumb and first finger, then place the needle onto the paper and gently spin the pencil around the needle, keeping the needle completely still to create a circle. What are the parts of the circle?At sea, a ship's compass must also be corrected for errors, called deviation, caused by iron and steel in its structure and equipment. The ship is swung, that is rotated about a fixed point while its heading is noted by alignment with fixed points on the shore. A compass deviation card is prepared so that the navigator can convert between compass and magnetic headings. The compass can be corrected in three ways. First the lubber line can be adjusted so that it is aligned with the direction in which the ship travels, then the effects of permanent magnets can be corrected for by small magnets fitted within the case of the compass. The effect of ferromagnetic materials in the compass's environment can be corrected by two iron balls mounted on either side of the compass binnacle in concert with permanent magnets and a Flinders bar. [32] The coefficient a 0 {\displaystyle a_{0}} represents the error in the lubber line, while a 1 , b 1 {\displaystyle a_{1},b_{1}} the ferromagnetic effects and a 2 , b 2 {\displaystyle a_{2},b_{2}} the non-ferromagnetic component. [33] Among the Four Great Inventions, the magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty (since c. 206 BC), [1] [2] and later adopted for navigation by the Song Dynasty Chinese during the 11th century. [3] [4] [5] The first usage of a compass recorded in Western Europe and the Islamic world occurred around 1190. [6] [7] 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. The magnetic field exerts a torque on the needle, pulling the North end or pole of the needle approximately toward the Earth's North magnetic pole, and pulling the other toward the Earth's South magnetic pole. [8] The needle is mounted on a low-friction pivot point, in better compasses a jewel bearing, so it can turn easily. 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. The eight half-winds are the direction points obtained by bisecting the angles between the principal winds. The half-winds are north-northeast (NNE), east-northeast (ENE), east-southeast (ESE), south-southeast (SSE), south-southwest (SSW), west-southwest (WSW), west-northwest (WNW), and north-northwest (NNW). The name of each half-wind is constructed by combining the names of the principal winds to either side, with the cardinal wind coming first and the intercardinal wind second.

If breaking down for study/signalling the subcomponents are called the "principal" followed by the "cardinal" wind/direction. As a mnemonic (memory device), minds familiar encode the meaning of "X by Y" as "one small measure from X towards Y". It can be noted such measure is 11 + 1⁄ 4°. So, for example, "northeast by east" means "one quarter of the gap from NE towards E".Lee, Robert E. (2011). "Compass Rose". University of Washington. Archived from the original on February 21, 2015.