What is the common instrument used for measuring direction?

The lensatic compass is the most widely used instrument for measuring direction because it is specifically designed for navigation and orientation. Its design allows for accurate reading of degrees relative to magnetic north, which is crucial for soldiers and outdoor enthusiasts who often need to navigate in the field without reliance on technology that may fail due to battery issues or signal loss.

The lensatic compass typically includes a magnetic needle that aligns itself with the Earth's magnetic field, a sighting bezel for taking precise bearings, and a clear lens for visibility. This allows the user to determine their direction efficiently and reliably in various environments, making it a fundamental tool in military and survival situations.

While GPS devices can give a directional readout, they also rely on satellite signals, which may not always be available in all conditions. Clinometers are used for measuring angles of slope, elevation, or depression rather than direction. Similarly, altimeters measure altitude based on atmospheric pressure and are not designed to provide directional information. Thus, the lensatic compass remains the clear choice for measuring direction effectively.