Scale

Expression of Scale

Scale can be expressed as a ratio (1:40,000), a representative fraction (1/40,000) or as an equivalent (1" = 500'). Ratios indicate that 1 unit on the photo or map is equal to "x" number of units on the ground. For example, at a scale of 1:40,000 one inch on the photo or map would equal 40,000 inches or approximately 3,333 feet on the ground. Representative fractions act in the same way as ratios. Equivalents describe scale by using different units of measurement. For example, at a scale of 1" = 500' one inch on the photo or map would equal 500 feet on the ground.

Large Scale versus Small Scale

There is often confusion as to whether a photo or a map is either large or small scale. Large-scale maps and photos show features at a larger more detailed size. Small-scale maps and photos show features at a smaller less detailed size. Large-scale maps and photos cover smaller areas, while small-scale maps and photos cover larger areas. An example of a large scale would be 1:2,000 (1 inch on the photo or map equals 2,000 units on the ground). An example of a small scale would be 1:40,000 (1 inch on the photo or map equals 40,000 inches on the ground).