Prismatic compass

A prismatic compass is a tool used in navigation and surveying to help find directions and measure angles. It is useful for figuring out directions during surveys. This compass uses a magnetic needle to find direction, and distances can be measured with a tape, chain, or a laser range finder.

The prismatic compass is named for the special prism it uses, which helps make observations more accurate. Surveyors use it to create lines called traverses. They take two directions for each line, and these should differ by exactly 180^° if there are no special effects on the compass, known as local attraction. This tool helps make sure surveys are precise and correct.

Least count

Least count means the smallest amount an instrument can show. For a prismatic compass, this is 30 minutes. This means the compass can only show angles that are multiples of 30 minutes.

Bearings

A compass helps you find directions by measuring angles. It uses a system called the whole circle bearing. This system measures angles from 0 to 360 degrees clockwise from magnetic north. This helps figure out the angles between different paths when you are exploring. There are simple rules to find these angles, depending on which way you are going.