Before the invention of the compass, it was impossible to divide the square of the earth very finely. There are only eight directions, north, northeast, east, southeast, south, southwest, west and northwest, which can be used to describe the direction and orientation. Feng Shui is represented by eight diagrams: Kangua represents the north, Gengua represents the northeast, Zhengua represents the east, Yijigua represents the southeast, Liyu represents the south, Kungua represents the southwest, Dugua represents the west and Gangua represents the northwest.
Sun Gui's positioning divides the ground plane into twelve equal parts, and uses twelve earthly branches: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai to express the orientation.
With the development of processing industry, the magnetic needle has changed from the initial spoon row to the needle shape, and from the floating magnetic needle to the thimble, which has made a qualitative change in the measurement accuracy of the compass. In the Tang Dynasty, Yang Junsong combined the Eight Diagrams and the Twelve Branches into one, and added all the heavenly stems A, B, C, D, E, Kyrgyzstan, Geng, Xin, Ren and Guangxi to the earthwork system to indicate the position except the two branches of E and Kyrgyzstan. Thus, 360 degrees around the horizon is divided into twenty-four equal parts, called twenty-four mountains, each of which accounts for fifteen degrees, and three mountains are a divination, each of which accounts for forty-five degrees. Since the founding of the Tang Dynasty, 24 mountains have been preserved. Therefore, the site of Twenty-four Mountains is one of the main levels in Pan Yang. In the north, there are three mountains: Renzi, Zi and Gui, which belong to the acquired Kangua and the acquired Kungua respectively. Three mountains in the northeast are ugly, ugly and awkward. The day after tomorrow, they belong to divination, which belongs to congenital divination.
The three mountains in the east, A, Mao and B, belong to the deviation between acquired divination and postnatal divination; The three mountains in the southeast are Chen, Xun and Si, the day after tomorrow belongs to Xun Gua, and the congenital belongs to Du Gua;
The three mountains in the south, C, noon and D, are separated from divination the day after tomorrow and are divination for the day after tomorrow; The three mountains in the southwest are not Kun and Shen, and the day after tomorrow belongs to Kun Gua, and the congenital belongs to Kun Gua;
compass
Xisanshan, Geng, You and Xin belong to acquired divination, and divination is congenital; The three mountains in the northwest, dry and sea, belong to the post-day dry divination and congenital divination.
The compass consists of three parts:
paradise lake
Also known as the bottom of the sea, it 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 (seabed) of Tianchi Lake, which is called the 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 seabed of modern compasses is painted with a cross, and the top of the cross is printed with southeast and northwest respectively. When in use, the northern end of the magnetic needle should point to the northern end of the submarine reticle, and the magnetic needle should coincide with the north-south line of the submarine.
inner disc
It's the turntable next to the compass. Many concentric circles are printed on the inner disk, and one circle is called a layer. Each floor is divided into different equal parts. Some floors have more squares, while others have fewer squares. The least floor is divided into eight squares, and the most floor has 384 squares. Different characters are printed on each grid. There are many kinds of compasses, some with many layers, some with few layers, the most with 52 layers, and the least.
compass
There are only five floors.
The contents of the compass are printed on different circles (layers) of the inner disk, which is the main component of the compass. All feng shui schools put the main content on the compass, making China's compass an encyclopedia of China's skills.
Outer disk
The outer disk is square, which is the tray of the inner disk. There is a small hole at the midpoint of the outer side of the four sides, and the red line penetrates into the ten meridians of Tianxin, which is used to read the contents of the inner disk. The ten directions of Tianxin are required to be perpendicular to each other, and the new compass you just bought must be calibrated before use.
Compass is a basic tool to measure the magnetic azimuth of the earth's surface, which is widely used in military, navigation, surveying and mapping, forestry, exploration, construction and other fields.
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.