ABSTRACT

The scale of a map represents the ratio of the distance between two points on a map to the corresponding distance on the surface of the Earth. Map Scale is Map Distance divided by Ground Distance. Suppose one inch on the map represents one mile on the surface of the Earth. There are a several common ways to express this idea. Verbal Scale simply states the relationship as: “One inch represents one mile.” A Bar Scale shows graphically the relationship between the map distance and the surface distance, and is typically used to visualize distances on a map. Finally, map scale may be represented as a numerical ratio, called a Representative Fraction (RF), which is free from units. If, for example, RF = 1/24,000, then one meter on the map represents 24,000 meters on the surface of the Earth. Or, one foot on the map represents 24,000 feet on the surface of the Earth. It is convenient to capture the idea using notation such as 1:24,000, 1:63,360 (which is a scale of one inch to one mile), or 1:1,000,000.