A depression is indicated by which contour pattern?

A depression is indicated by which contour pattern?

• A. Tick lines that extend from the cut line to the roadbed
• B. Concentric circles
• C. Tick lines extending from filled area to lower ground
• D. Closed contour lines with tick marks pointing toward low ground

Answer: (D)

Depressions are shown on topographic maps by closed contour lines that have short hatch marks (tick marks) on the inside of the loop, pointing toward the lower ground. Those inward ticks signal that elevations decrease toward the center, marking a sunken area like a crater or basin. The plain closed loop without ticks could represent a hill or other feature, and patterns involving ticks in other locations aren’t the standard way to indicate a depression. So the pattern with closed lines and inward-pointing tick marks correctly indicates a depression.

Depressions are shown on topographic maps by closed contour lines that have short hatch marks (tick marks) on the inside of the loop, pointing toward the lower ground. Those inward ticks signal that elevations decrease toward the center, marking a sunken area like a crater or basin. The plain closed loop without ticks could represent a hill or other feature, and patterns involving ticks in other locations aren’t the standard way to indicate a depression. So the pattern with closed lines and inward-pointing tick marks correctly indicates a depression.