[Image: Image of a topographic map]Definition: Topographic maps or “quad sheets” are printed maps that portray the relief of the landscape. In addition, they also display physical features such as roads, buildings, rivers and creeks.
Scale: The most common used topographic map is the 7.5 minute map which has a scale of 1:24,000 or 1 inch = 2,000 feet. In any case, scale is displayed at the bottom of the map.
Relief: Changes in elevation are shown by a series of contour interval lines. These lines represent a point’s elevation above sea level. Any point along a line is the same elevation as any other point on the same line. The closer the contour lines are to each other, the steeper the slope. The elevation distance between the lines is usually 5 or 10 feet. This information is given at the bottom center of the map. The elevation is frequently printed along several of the contour lines.
Determining slope: Determine the elevation change between two points from the contour lines, being sure to use the proper contour interval. Divide this change by the distance between the two points, using the scale at the bottom of the map. Multiply by 100 to get the percent slope.