In contour mapping, what do closely spaced contours indicate?

Closely spaced contours on a contour map indicate steep slopes. This is because the spacing between contour lines represents the change in elevation over a given horizontal distance. When the lines are close together, it signifies that there is a rapid change in elevation, which is characteristic of steep terrain. In contrast, if the contours are further apart, it suggests a more gradual slope. This understanding is crucial for interpreting topographic maps, as it helps in visualizing the terrain's gradient and can have practical applications in fields such as surveying, land use planning, and environmental assessment. The interpretation of contour lines is fundamental for engineers, architects, and planners when evaluating land for various projects.