Cover Mapping Land, continued

Materials

Procedure

  1. Ask students to locate their watershed on both their map and satellite image.
  2. Introduce the concept of spectral reflectance. Each type of vegetation or material covering the land reflects or emits a unique electromagnetic signature, thus being recorded by the satellite sensor as unique and ap-pearing as a uniquely colored entity on the satellite image. With a grease pencil on the laminated satellite image, outline ten areas in your watershed that appear distinctly different on the image and thus indicate different land covers.
  3. On the basis of their knowledge of the area, your students should record what might be the ground cover on each of several areas which are close enough to the school for a field trip to test their accuracy.
  4. Take your students on a field trip to a few of the representative sites. Bring along the maps, images, and outlines as you visit the various parts of the watershed. Your students should record the cover in each of the areas that they outlined. Have them compare their predictions of land cover to what is actually there.
  5. Back in the classroom, have your students reconsider the accuracy of their predictions on the basis of the evidence from their ground truthing.

Questions

Organize a discussion with your students by asking the following questions:
  1. What vegetation symbols appear on the map and how do they compare with the remotely sensed images?
  2. Which is older, the map or the satellite image? Other than the date printed on the map and image, what indicates that one is older than the other?
  3. How does the appearance of towns and cities differ between the map and satellite image?
  4. If the contour lines on the map were erased, what clues would you have about the location of high land? The remotely sensed image has no contour lines, can the students find clues as to the outline of the watershed?
  5. What indicates that the deeper and more fertile soils are on the low or the high land?
  6. How would your students describe the texture of the different cover classes that you see on the satellite image?
  7. What percentage of the local watershed is covered by forest, grasslands, agriculture, human settlements, etc.?

Evaluation

  1. Describe several ways in which satellite images are different from topographic maps.
  2. Locate and name all the land cover types you can find on the satellite image.
  3. Locate and name all the land cover types you can find on the topographic map.
  4. Explain how different types of land cover affect runoff and infiltration.
  5. Describe several human activities that change land cover and thereby decrease water quality. Explain the impacts.
  6. Suggest some possible changes in land cover that humans could make in the watershed to increase water quality.
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Last modified prior to September, 2000 by the Windows Team

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