How are the features of a depression represented on the contour lines?

Depressions are represented on topographic maps by enclosed contour lines that have tick marks pointing inward toward the lower elevation. These tick marks indicate that the area inside the closed contour represents a depression or a dip in the terrain, which is opposite to a hill or mound where contour lines would simply be closed without ticks.

Understanding the representation of depressions is crucial for land navigation and terrain interpretation, as it informs navigators about potential terrain challenges or features. The use of tick marks is a standardized method in cartography to ensure clarity and prevent confusion with other geographic features, like hills, where contour lines would normally close but without any tick marks.