Prismatic compass

A prismatic compass is a navigation and surveying instrument which is extensively used to find out the bearing of the traversing and included angles between them, waypoints (an endpoint of the course) and direction.

The included angles can then be calculated using suitable formulas in case of clockwise and anti-clockwise traverse respectively.

The name Prismatic compass is given to it because it essentially consists of a prism which is used for taking observations more accurately.

[3] Least count means the minimum value that an instrument can read which is 30 minutes in case of prismatic compass.

[5] The included angles can be calculated by the formulas F-P ±180 in case of anti-clockwise traverse and P-F ±180 in case of clockwise traverse, where 'F' is the fore bearing of forward line in the direction of survey work and 'P' is the fore bearing of previous line.