Where does the S of the compass point?

There are four letters in the guide, which are English abbreviations, in which "S" stands for South, "W" stands for West, "E" stands for East and "N" stands for North.

Compass is the result of China ancient working people's understanding of magnet magnetism in long-term practice. As one of four great inventions of ancient china, its invention has played an inestimable role in the development of human science, technology and civilization. In ancient China, the compass was first used for rituals, etiquette, military affairs and divination, and to determine the orientation when looking at geomantic omen.

Compasses are often used in navigation, geodesy, travel and military affairs. The invention of the compass with physical direction indication has three parts, namely Sina, compass and magnetic needle, all of which belong to the invention of China. According to ancient mine records, it first appeared in the Cishan area during the Warring States Period.

Extended data:

Application of compass

1, principle of electronic compass

The three-dimensional electronic compass consists of three-dimensional magnetoresistive sensor, biaxial tilt sensor and single chip microcomputer. The three-dimensional magnetoresistive sensor is used to measure the earth's magnetic field, and the inclination sensor is used to compensate when the magnetometer is not horizontal. Single-chip microcomputer processes the signals of magnetometer and inclination sensor, as well as data output and soft iron and hard iron compensation. The magnetometer adopts three vertical magnetoresistive sensors, and each sensor detects the geomagnetic field intensity in the axial direction.

2. Magnetic declination

The angle between the magnetic meridian circle at any point on the earth's surface and the geographical meridian circle is the magnetic declination. The magnetic declination is not constant in the same place, and the magnetic declination measured in the morning and evening is slightly different every day. Magnetic declination has the characteristics of long-term variation and periodic variation. Meteorological conditions also have a great influence on the magnetic declination, especially in lightning weather. Magnetic declination is greatly influenced by geomagnetic environment. Due to the characteristics of geomagnetism, magnetic meridian is complex and non-parallel. The longer the straight line, the greater the error.

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