Here's a breakdown:
* Closed Contour Lines: Contour lines are lines that connect points of equal elevation. When these lines form a closed circle or oval, it indicates an area that is lower than the surrounding terrain.
* Hachures: These are short, evenly spaced lines drawn perpendicular to the contour lines inside the closed contour. They point towards the lower elevation inside the depression. The density of hachures indicates the steepness of the depression's sides.
Visualizing it:
Imagine a bowl. The rim of the bowl would be represented by the closed contour lines. The inside of the bowl, where the elevation drops, would be filled with hachures pointing towards the bottom.
Example:
Imagine a topographic map of a valley. The valley floor would be shown as a closed contour line with hachures pointing towards the center of the valley. The higher ground surrounding the valley would be represented by contour lines at higher elevations.
Key points to remember:
* The higher the elevation of a contour line, the further apart the lines are.
* The closer the contour lines are together, the steeper the slope.
* The direction of hachures indicates the direction of the slope within the depression.
Understanding how depressions are represented on topographic maps is crucial for interpreting the terrain and understanding its features.
