What tool is used to measure the grid azimuth on a military map?

The tool used to measure grid azimuth on a military map is the protractor. A protractor is specifically designed to measure angles, and in the context of military maps, it allows users to accurately determine the direction of movement or the angle between two points in relation to the grid lines on the map.

When navigating or planning maneuvers, understanding the grid azimuth is crucial for aligning movements with map coordinates and ensuring accurate positioning on the battlefield. The protractor's design often includes a transparent base to help align it with map features and grid lines, thereby increasing the precision of the readings obtained.

While a compass is used for navigation and determining magnetic azimuths, it does not measure grid azimuths directly on a map. A ruler can assist in measuring distances but does not measure angles, and a caliper is generally used for precise measurements of small objects or dimensions and is not applicable to mapping azimuths. Therefore, the protractor is the correct choice for measuring grid azimuths in military applications.