Plain scale

A plain scale, also known as a simple scale, is a type of scale used in cartography, surveying, and technical drawings to represent distances, sizes, or quantities on a map or plan. It is a line or bar that has its length proportional to a fixed unit of measurement in the real world, with markers or ticks indicating units of measurement along the scale. The user can measure the length of an object or distance on the map, and then compare it to the corresponding length on the plain scale to determine its actual size in the real world.