Quick Answer
Elevation gain versus loss can be calculated by measuring the vertical distance between contour lines and adding or subtracting it from your starting elevation, using a scale and key to determine contour interval.
Calculating Contour Intervals
When reading a contour map, it’s essential to identify the contour interval, which represents the vertical distance between each contour line. This can be found in the map’s key or legend. For example, a contour interval of 20 feet means that each contour line represents a 20-foot change in elevation.
Using Contour Lines to Estimate Elevation Gain or Loss
To calculate the elevation gain or loss, measure the vertical distance between contour lines. This can be done by using a ruler or a measuring device. For instance, if you’re ascending and the contour interval is 20 feet, and you move from a contour line at 1000 feet to one at 1200 feet, your elevation gain is 200 feet. If you’re descending, the elevation loss would be 200 feet.
Understanding Contour Map Scales
A contour map’s scale is used to convert map measurements to real-world distances. It’s expressed as a ratio of map distance to actual distance. For example, a scale of 1:24,000 means that one inch on the map represents 24,000 inches (or 2000 feet) in real life. This scale allows you to calculate the actual distance and elevation gain or loss between contour lines.
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