Should the magnetic declination be adjusted when using the compass?

Geomantic omen mainly depends on the magnetic meridian and the north and south poles, and the degree is subject to the magnetic direction, because the magnetic field is the root that affects geomantic omen, and the positive and negative poles are used to distinguish the geographical direction. In fact, the ancients have long discovered the magnetic declination. Moreover, Lai Wenjun, a Feng Shui master in the Song Dynasty, also measured the declination of 7.5 degrees, and made a layer of human hands on the compass, meaning that the afternoon was in the middle, the geography was due south, and Renzi was due north. He takes Polaris as the standard for inspection and measurement, because Polaris is always in the north, and the angle between magnetic north and Polaris in the compass is the magnetic declination. Therefore, the needle in the human plate is the north and south of geography. Geography teachers don't use it to set the direction of geomantic omen, but only use it to remove sand. However, it can be used to distinguish the geographical north-south direction. In fact, people who know how to look at Polaris can also measure the local magnetic declination with a compass. The method is to point the meridian of the compass at Polaris, and then turn the compass sky disk to make the red line of the compass coincide with the pointer. Then the angle between the meridian and the pointer is the magnetic declination.