A prismatic compass is a type of compass commonly used for measuring bearings or directions in surveying, navigation, and outdoor activities. It consists of a magnetic needle or card that aligns with the Earth's magnetic field, indicating the direction of magnetic north. The compass is housed in a metal or plastic casing, with a prism and sighting vanes for more accurate readings. To use a prismatic compass, the compass is held level and the magnetic needle is allowed to settle. The sighting vanes are then aimed at the target, and the bearing is read through the prism. The graduated bezel can be rotated to align with the needle, providing a reading in degrees or mils. Prismatic compasses are widely used in surveying, mapping, forestry, and outdoor activities such as hiking and orienteering. They are valued for their accuracy, reliability, and simplicity, making them essential tools for navigation and direction-finding in various environments.