When contour lines are very close together on a map, what does it indicate?

When contour lines are very close together on a map, it indicates a steep slope or cliff. This proximity of contour lines signifies a rapid change in elevation over a short horizontal distance. Essentially, when you see closely spaced lines, it means that as you move even a small distance, you are gaining or losing a considerable amount of height.

In contrast, when contour lines are spaced further apart, it indicates a gentle slope where the change in elevation occurs more gradually. Flat terrain would have very sparse contour lines or none at all, and bodies of water are generally represented with blue areas and do not have contour lines that indicate elevation. Thus, the characteristics of closely spaced contour lines unequivocally point to steep terrains, making the understanding of this concept critical for land navigation and map reading.