Why do some modern compass have holes?

If you're referring to the triangle and circle on the front of the baseplate, as in those are for hand-drawing an orienteering (land navigation) course on a map. Something like the following (which is a course done on a printing press, but smaller... read more

Most types of compass would help you to find your way and therefore potentially help you to save you own life should you need to reach a safe haven - and you know both your location and the location of said safe haven relative to your own. read more

A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions. Usually, a diagram called a compass rose shows the directions north, south, east, and west on the compass face as abbreviated initials. When the compass is used, the rose can be aligned with the corresponding geographic directions; for example, the"N" mark on the rose points northward. Compasses often display markings for angles in degrees in addition to the rose. read more