I'm still confused about the concept of east, west, north and south, and I want to ask how to fully understand it. "

The afternoon sun is in the west.

It should be in the south at noon.

You can't see the sun in the north of China.

Just figure out the general direction.

The direction on the earth is artificially specified. According to these directions, people can determine the mutual position relationship between different parts of the surface. Generally speaking, the direction is relative. A place can be east, west, south and north, because it refers to different places. As shown in Figure 2-7, A is due east of B; For c, it is due west; For d, it is due south; For e, it's due north again. However, the South Pole and the North Pole are exceptions. There is no relativity in this direction. For any other place on earth, the South Pole can only be due south; The North Pole can only be located in the north direction of all other places on the earth. So on the earth, only the horizon direction of the north and south poles is absolute.