Map protractor
A map protractor is a tool used to measure direction angles on a map.
It is usually a plate made of transparent plastic on which a clockwise divided circle is attached. A grid of lines can be found within the circle, which enables the protractor to be positioned in the direction of true north on the map.
For use, the protractor is placed with its center marking on your own location, paying attention to the correct north positioning. The direction you are looking for can be read on the graduation with the thread attached in the middle of the graduation.
Because of its dimensions, a map protractor is more accurate than working with the graduation of a mirror compass .
In addition to the circular division, there are usually additional divisions on the plate such as map indicators in various scales .