What is geomantic magnetic field location?

If you use a compass, you will know that, first, the pointer is jumping wildly. Second, the needle is shaking. Third, the needle is stuck. Fourth, the same house, measured at different points, the azimuth angle is wrong (this can be seen on the main disk, but not on the disk). Five, at the same point, the compass changes direction, the pointer will not be on the same line, such as the first measurement of 90 degrees and 270 degrees, Luo Yuan from 90 degrees to 270 degrees, 270 degrees to 90 degrees, but the pointer will not reverse to the original line, there is a degree of deviation. All the above situations are magnetic field chaos. The chaotic magnetic field indicates that there are some uncertain factors in the house.