Examine how the contour lines on the topographic map interact. Why do the lines on a topographic map never cross? How do the lines indicate which side of the mountain is the steepest?
The Correct Answer and Explanation is :
Why Do Contour Lines Never Cross on a Topographic Map?
Contour lines on a topographic map represent points of equal elevation. Since a single point on the Earth’s surface cannot have two different elevations simultaneously, contour lines never cross. If they did, it would imply that the same location has two different heights, which is physically impossible in normal terrain. The only exception to this rule is in cases of overhanging cliffs or caves, where the vertical component is not represented accurately in a two-dimensional topographic map.
How Contour Lines Indicate Steepness
The spacing of contour lines on a topographic map reveals the steepness of the terrain. When the lines are closely packed together, the elevation changes rapidly over a short distance, indicating a steep slope. Conversely, widely spaced contour lines signify a gentle slope, where the elevation changes gradually. The steepest side of a mountain or hill is the area where contour lines are closest together, as this means there is a significant vertical gain over a short horizontal distance.
Interpretation of Contour Patterns
- Concentric Circles: Contour lines that form closed loops represent hills or mountains, with the smallest loop at the peak.
- V-Shaped Patterns: When contour lines form a “V” shape pointing uphill, they indicate a valley or stream. The “V” points upstream.
- Depressions: Hachured contour lines (lines with short marks inside the loop) indicate a depression or crater.