Quick Answer
Contour lines that are close together indicate steep slopes because they represent a narrow distance between two points of the same elevation, signifying a sharp change in elevation. This proximity suggests a more vertical terrain, characteristic of steep slopes. The closer the lines, the more pronounced the slope.
Understanding Contour Lines
Contour lines are essential in navigation maps, particularly in wilderness areas or mountainous regions. These lines represent the Earth’s surface, connecting points of equal elevation. When contour lines are far apart, it signifies a gentle slope, whereas close lines indicate a steep slope. The distance between contour lines is crucial in determining the terrain’s steepness.
Calculating Contour Line Spacing
To estimate the steepness of a slope, calculate the vertical distance between two consecutive contour lines. In the United States, the standard contour interval is 40 feet, but it can vary depending on the map scale and region. For example, a map with a 20-foot contour interval will display more detailed information about the terrain. Measure the vertical distance between two lines, and then use the map’s scale to convert it to a more understandable unit, such as meters or feet.
Identifying Steep Slopes
When contour lines are close together, it’s essential to recognize the terrain’s steepness. A common technique is to look for lines that are parallel to each other, indicating a constant slope. In such cases, the distance between the lines is critical. For instance, on a map with a 20-foot contour interval, contour lines that are 50 yards apart may indicate a gentle slope, while lines that are 20-30 yards apart suggest a steeper slope. Always verify the map’s scale and contour interval to ensure accurate terrain assessment.
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