What is a contour interval?

A contour interval is defined as the difference in elevation between adjacent contour lines on a topographic map. This interval helps to indicate the steepness of the terrain; a smaller contour interval suggests a more gradual slope, while a larger interval indicates a steeper gradient. Understanding contour intervals is crucial for interpreting the maps, as they provide essential information about the landscape's shape and elevation changes without needing to measure directly.

The other options refer to different geographical features or measurements: the elevation of a lake is a specific point measurement, the total height of a mountain does not give information about the change in elevation between lines on a map, and the depth of the ocean relates to underwater topography but is not relevant to contour lines, which specifically detail land elevation. The focus of contour intervals is solely on how elevation changes across a given area, making that definition essential for understanding topographic maps.