What is the contour interval on a map?
The contour interval is the elevation distance between two contour lines on a topographic map. A contour interval of 20 meters, then, indicates that there is a difference in elevation of 20 meters between two adjacent contour lines.Topographic MapsThe major feature of topographic maps is the use of contour lines to describe the surface features of the Earth. When interpreted together, contour lines reveal hills, valleys, cliffs, ridges and other important terrain features.Contour LinesContour lines connect adjacent points of the same elevation. A contour line with an elevation of 500 meters connects all the continuous points with an elevation of 500 meters. Contour lines also never cross each other.Types of Contour LinesOn most topographic maps and those published by the United States Geologic Survey, three types of contour lines are used to indicate elevation of the ground: index contour lines, intermediate contour lines and index contour lines.Intermediate Contour LinesMost of the co
