A compass traverse is a method of filling in detail on a topographic, geologic, or other map. It is a method of surveying a route such as a stream, path, or the edge of an outcrop by means of a series of traverse legs , of each of which the bearing is observed by compass and the length measured directly in the field. It may be described as a zig-zag. The traverse may be closed or open depending on whether or not it returns to the starting point. An area may be surveyed by means of a grid of traverse lines.
For many centuries mariners have navigated by a series of courses, dictated usually by the wind, the bearing of each course being given by the compass and the length from an estimate of speed and elapsed time. The resulting dead reckoning was checked at suitable intervals by astronomical observation or from bearings to known points. Many coastlines were surveyed in this manner, but although there is no exact record when the method was first used in land