Using the contour lines, you can see that the hill has a sharp rise of about 200 ft and then the slope becomes less steep as you proceed right.įigure 2.29: Portion of a USGS topographic map of Stowe, VT. You can tell this because the contour lines there are closely spaced. For example, on this topographic map of Stowe, Vermont (Figure 2.29), you will see a steep hill rising just to the right of the city of Stowe. So, contour lines show the three-dimensional shape of the land. Contour lines that seem to touch indicate a very steep or vertical rise, like a cliff or canyon wall. In contrast, broadly spaced contour lines indicate a shallow slope. Closely-spaced contour lines indicate a steep slope, because elevation changes quickly in a small area. Contour lines can indicate the slope of the land.How does a topographic map tell you about the terrain? Well, in reading a topographic map, consider the following principles: If the difference between two bold lines is 100 feet and there are four lines between them, what is the contour interval? If you answered 20 feet, then you are correct, 4+1=5, right? So, the calculation would be: (100 ft/5 = 20 ft). Divide that difference by the number of contour lines between them, PLUS 1. Take the difference in elevation between 2 bold lines.The legend on the map will also tell you the contour interval. This difference between contour lines is called the contour interval. Two contour lines next to one another are separated by a constant difference in elevation (e.g.That would mean one place had two different elevations, which cannot happen. The contour lines run next to each other and NEVER cross one another.The bold contour lines are labeled with numerical elevations. Each contour line represents a specific elevation and connects all the places that are at the same elevation.Let's take a closer look at this (Figure 2.28). What makes a topographic map different from other maps? Contour lines help show various elevations.įigure 2.28: Topographic map of Swamp Canyon Trail portion of Bryce Canyon National Park.Ĭontour Lines and Intervals Ĭontour lines connect all the points on the map that have the same elevation. This type of map is called a topographic map (Figure 2.28). You need a special type of map to represent the elevations in an area. Where are the hills and valleys located? How high are the canyon walls? Which way will streams or rivers flow? But nothing on the map shows the height of the terrain. You see some markers for campsites, a picnic area, and a shuttle bus stop. You can see a green line which is the main road. Now look at the corresponding section of the Visitor's map (Figure 2.27). Figure 2.27: Portion of Bryce Canyon National Park road map. There are high and low points between the cliffs.įigure 2.26: View of Bryce Canyon National Park. The terrain clearly has many steep cliffs. You can see the rugged canyon walls and valley below. Look at this view of Bryce Canyon National Park, Utah (Figure 2.26). A topographic map will show you that the road bends to go around a hill or stops because that When you use a regular road map, you can see where the roads go, but a road map doesn't tell you why a road stops or bends. Contour lines are drawn on a topographic map to show the location of hills, mountains and valleys. Topographic maps use a special type of line, called a contour line, to show different elevations on a map. Topographic maps represent the locations of major geological features. Mapping is a crucial part of earth science. Explain how various earth scientists use topographic maps to study the Earth.Explain how to read and interpret a topographic map.
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