What are common mistakes when reading contour lines?

Misinterpreting Slope Shape

Reading contour lines involves identifying the shape of a slope, which is crucial for navigation. A common mistake is misinterpreting a concave slope as convex or vice versa. To avoid this, look for the direction of the slope’s curvature. If the contour lines are converging, the slope is likely to be steeper on the side where they converge. This rule of thumb helps to identify the shape of a slope, allowing you to make more accurate decisions about your route.

Failing to Recognize Natural Features

Contour lines often correspond to natural features such as ridges, valleys, and hills. Failing to recognize these features can lead to navigation errors. To identify natural features, look for changes in the contour line pattern. For example, a series of closely spaced contour lines may indicate a steep slope or a valley, while widely spaced contour lines may indicate a gentle slope or a plateau. By recognizing these patterns, you can more easily identify natural features and make informed decisions about your route.

Estimating Elevation Changes

Estimating elevation changes is critical for navigation, as it helps you to understand the terrain and make informed decisions about your route. A common mistake is underestimating the elevation change between two points. To avoid this, use the contour interval on the map to estimate the elevation change. For example, if the contour interval is 50 feet and there are 5 contour lines between two points, the elevation change is approximately 250 feet. By using the contour interval to estimate elevation changes, you can make more accurate decisions about your route and avoid navigation errors.