What is the development process of compass?

Compass is actually a tool to measure the square of the ground by using the principle of compass positioning. Compass is used in geomantic omen to cover dragons, remove sand, receive water and determine the sitting direction of buildings. Before the invention of the compass, it was impossible to divide the square of the earth very finely. Only eight directions, north, northeast, east, southeast, south, southwest, west and northwest, can be used to describe the direction and orientation. Sun-Gui positioning divides the ground plane into 12 equal parts, and uses twelve earthly branches: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai to represent the orientation. With the development of processing industry, the magnetic needle changes from spoon to needle, and from floating magnetic needle to thimble, which makes the measurement accuracy of compass change qualitatively. The compass consists of Tianchi, an inner disk and an outer disk: Tianchi, also known as "the seabed", is the compass. The Tianchi of the compass consists of thimble, magnetic needle, submerged wire, cylindrical outer box and glass cover, which are fixed in the center of the inner disk. There is a sharp thimble in the center of the bottom surface of the round box, and a concave hole in the center of the bottom surface of the magnetic needle, and the magnetic needle is placed on the thimble. The arrow of the compass points south at one end and north at the other. There is a red line at the bottom of Tianchi Lake, called "submarine line", and there are two red dots on both sides of the northern end. When in use, it is necessary to make the northern end of the magnetic needle coincide with the seabed line. The inner disk is a rotatable disk next to the outside of the compass. Many concentric circles are printed on the inner disk, and one circle is called "one layer". Each layer is divided into different equal parts, some layers have more grids, some layers have less grids, the least one is only divided into 8 grids, and the layer with the most grids has 384 grids. Different characters are printed on each grid. The contents of the compass are printed on different circles on the inner disk, which is the main component of the compass. The ancients in our country believed that the gas field of human beings was controlled by the gas field of the universe, that harmony between human beings and the universe was good, and disharmony between human beings and the universe was evil. Therefore, the ancients put all levels of information in the universe, such as the stars in the sky, the five behaviors on the earth and everything represented by heavenly stems and earthly branches, on the compass by experience. Geomantic omen is to find the most suitable position or time for a specific person or thing through the rotation of a magnetic needle. Although the concept of "magnetic field" is not mentioned in geomantic omen, the coordination of the directions, orientations and intervals of each layer on the compass implies the law of "magnetic field". The invention and application of the compass is the result of human beings' continuous exploration of the mysteries of the universe, society and life. The information marked on the compass contains a lot of wisdom of ancient people in China.