What are the three common aspects of compasses?

Compasses are often used in navigation, geodesy, travel and military affairs. Compass is one of the four great inventions in ancient China. When it was first invented, it was used for sacrifice, etiquette, military affairs, divination and geomantic omen.

What are the three common aspects of compasses?

The invention of compass has played an inestimable role in the development of human scientific and technological civilization.

Four great inventions of ancient china is: compass, papermaking, gunpowder, movable type printing.