Agricultural Engineering Practice Exam

A depression on a map is represented by a closed contour line that indicates the lowest elevation within a specific area. This feature is characterized by contour lines that form closed loops with higher values surrounding them, which signifies that the land slopes downward toward the center of the depression. In topographic mapping, such a depression could represent various geographical features, such as a sinkhole or a basin, where water may accumulate or where land dips relative to its surroundings.

The other options do not accurately reflect the characteristics of depressions. Areas of high elevation would be associated with closed contours that have lower numeric values inside and higher values outside, whereas flat land generally lacks significant elevation changes and would not include depressions. Water collection areas may occur in depressions, but that is not the sole or defining characteristic of a depression; rather, it is the lowest elevation aspect that is primarily indicated by closed contours on the map. Thus, understanding that depressions are characterized by their closed contour lines at the lowest point is key to interpreting topographic maps effectively.