Quick Answer
Contours on maps indicate elevation changes by using lines of varying thickness and color to represent different elevations. The lines are typically drawn at regular intervals, with more widely spaced lines indicating lower elevations and closely spaced lines indicating steeper slopes. This helps to create a visual representation of the terrain's shape and elevation.
Understanding Contour Lines
Contour lines are lines on a map that connect points of equal elevation. The distance between contour lines is known as the contour interval, and it can vary depending on the map’s scale and the terrain’s complexity. A typical contour interval is 10-20 meters, but it can be much larger for areas with minimal elevation changes.
Interpreting Contour Patterns
To pinpoint a location on a map using contour lines, look for patterns and shapes that indicate specific terrain features. For example, a closed contour line indicates a hill or mountain, while a contour line that opens up indicates a valley or depression. A U-shaped contour line can indicate a valley, while a V-shaped contour line can indicate a narrow valley or a ridge. By combining contour patterns with other map features, such as water sources and ridges, you can create a mental picture of the terrain and pinpoint your location.
Using Contour Lines to Estimate Elevation
To estimate the elevation of a point on the map, measure the distance between contour lines and multiply it by the contour interval. For example, if the contour interval is 10 meters and the distance between contour lines is 3, the elevation difference between the two lines is 30 meters. By adding or subtracting this elevation difference from the elevation of a nearby contour line, you can estimate the elevation of the point. This technique can be used to estimate the elevation of a summit, a valley bottom, or any other point on the map.
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