Maps are two-dimensional representations of specific areas of land or of sea. Of course the scale or size of the area has been greatly reduced. (This is why someone will say that something is built "to scale" if its measurements are the same as that of the real thing it represents.)
In order for the viewer of a map to understand distances on a geographic map which is greatly reduced from real life, a little ruler-like drawing which is called a scale is provided. The use of this scale to determine distance is called the graphic scale method.
- Representing distance
Usually near the bottom of a territorial map lie two scales, marked off as are rulers. One is a scale of miles, the other of kilometers. Underneath them is the ratio. For example, the ration may be 1 inch on the scale equals approximately 30 miles or 48.3 kilometers. Therefore, by taking a ruler or measuring tape, a person can measure the distance from one point to another on the map. Then, by referring to the graphic scale, a person can calculate the actual distance between these same points.
- Representing elevation
On topographic maps, there can be scales drawn to indicate elevation. For instance, a line of a certain size can represent a vertical increase in elevation of 100 feet.
- Representing location
Other scales can be used to pinpoint locations on a map. For example,the MGRS, or military grid reference system is what is called the geocoordinate standard that NATO militaries use for locating points on the earth. What is called a grid square is used; it can be a square with a side whose scale represents a length of 10km (6 mi.). Some topographic maps have a scale of 1:50,000; so when the MGRS is superimposed on the surface of the map, calculations can be made with each square in a grid representing a certain largedistance.
In geography, people use measurements for distance, height, elevation, and location (coordinates). A scale would be used for things like maps and diagrams because it is hard to make a map using the actual measurements. Maps use scales so that they can reduce the size and choose different units (like 1 inch = 1 mile) to represent the actual distances or measurements.