1. + Topographic Mapping

2. + Goals Define and describe topographic maps. Define and describe an elevation profile. Use a topographic map to create an elevation profile. Describe how NASA probes create topographic maps that are used to create elevation profiles.

3. + Describe a topographical map. What do the lines on the topographical map represent? How are the numbers used on the topographical map? What do you know about this geological feature based on the map? When might you use a topo map?

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5. + Topographical Maps Topographical, or topo, maps show changes in elevation with lines. To make a topo map, the elevation of the land is measured at regular intervals. Intervals with the same elevation are connected with lines to show that they are at the same elevation.

6. + Part 2: Comparing topo maps to elevation profiles: Which topo map matches each elevation profile? How do you know? How do topo maps show changes in elevation? What is the significance of the distance between lines on a topographical map?

7. + Challenge: Use elevation information to create a topo map. Good luck. Hint: Topographical maps have a set contour or elevation interval. All values that fall between this interval fall between these lines. This means that you don’t need a contour line passing through every elevation point.

8. + Activity

9. + Elevation profiles and negative integers When we measure elevation, where do we measure from? What is ‘0’ on Earth? The ocean has depths well over 2 miles. Should we measure everything from the lowest point on Earth? If not, where does it make sense to start measuring from?

10. + Key questions for the next slide… If sea level is 0, how do we write a number that is below sea level? If we are measuring a distance from and elevation below sea level to an elevation above sea level, how do we write an equation to find the difference?

11. + The concept of absolute value/negatives and elevation profiles The highest point in the United States is the summit of Mount McKinley (Denali) in Alaska. This mountain is 20,320 feet above sea level. The lowest point in the United States is in Death Valley California. Here, it is 282 feet below sea level. What is the difference in elevation between the summit of McKinley and Death Valley?