1. At the fixed point, first measure the position of the observation point in a certain terrain or feature; When measuring, open the compass cover, loosen the brake screw and let the magnetic needle rotate freely; When the measured object is relatively large, put the compass on the chest, aim the long level of the compass at the measured object, and then turn the reflector so that both the object and the long sight are reflected in the reflector, and the object, the tip of the short sight on the long sight and the center line of the reflector are located in a straight line, while keeping the compass horizontal (the bubble of the circular level is centered).
When the magnetic needle stops swinging, you can directly read the reading on the circular dial pointed by the magnetic needle, or press the brake screw to read it again.
2, the correct compass: hold the outer disk with both hands left and right, and separate your feet slightly. Then put the compass between the chest and abdomen to keep it horizontal, not high left and low right, nor high front and low back.
Adjust the compass. The crosshair above the compass needs to be parallel to the gate of the measured object. After the position of the crosshair is fixed, it is necessary to adjust the direction of the Tianchi pointer. Move the inner disk with both thumbs. When the inner disk rotates, Tianchi will rotate with it. Turn the inner disk until the magnetic needle stops and coincides with the red line of Tianchi.
How to use the compass? Video link? Web page link