Compass introduction

A compass is an instrument that uses a magnetic needle to determine the direction. It is used to measure the magnetic azimuth or magnetic quadrant angle of the ground line. A compass consists of a compass box, a sight and a magnetic needle. It is simple in structure and convenient to use, but its accuracy is low. It is often used to determine the general starting direction of independent investigation areas, as well as the investigation work in route survey, geological survey and forest survey.