What is contour interval?

A contour interval is the vertical distance between two contour lines on a topographic map. These lines represent points of equal elevation above a specific reference point, such as sea level. The contour interval is typically listed on the map legend, and can vary depending on the scale of the map and the topography of the area being represented.

Contour intervals are used to help understand the shape and elevation of the land, and are essential for hikers, surveyors, and other users of topographic maps. A smaller contour interval indicates steeper terrain, while a larger contour interval indicates flatter terrain. For example, a contour interval of 20 feet means that each contour line represents a change in elevation of 20 feet. Contour intervals can be measured in feet, meters, or other units of measurement depending on the map.