What units are primarily used for measuring direction?

The primary units used for measuring direction are degrees, mils, and gradians (commonly referred to as grads).

Degrees are a well-known measure of angles, with one full rotation equating to 360 degrees. This unit is widely used in navigation, surveying, and other disciplines where direction is relevant. Mils are particularly useful in military applications for artillery and field operations, as one mil corresponds to a specific angle at a distance, allowing for precise adjustments in targeting. Gradians, or grads, divide a right angle into 100 parts, making them useful in certain mathematical contexts and geographic calculations.

This combination of degree, mil, and grad allows for versatility and precision in measuring direction across various fields, making this set the most comprehensive for directional measurements. Other combinations would lack the same level of applicability or might not represent widely recognized units in various disciplines where direction is critical.