GROUP SIZE: Individual or Pairs
TIME: 60 minutes
TYPE OF ACTIVITY: Student Investigation
TEACHING STRATEGY: Expository Guided Discovery
CONCEPTS: Landsat Earth Resource Management
SKILLS: Interpreting Data Observation Following Direction
Objectives: To gain skill in the interpretation of satellite transmitted data about the earth; to consider the applications of data available from satellites to earth resource management; to consider the implications of earth data from satellites to the exploration of other planets.
Materials: Colored pencils (optional); study sheet; Landsat photos or one of the reference books suggested in the reference section of this lesson.
Teacher Background Information:
Landsat views the United States every 18 days sending back information in the form of “pixel” pictures which can be printed out in a format similar to the one on the study sheet or the computer can generate a photograph by interpreting the data and translating it into picture form. Each pixel segment, represented by the symbols: + , X , – , O , etc., covers an area 57 by 79 m ( 4503 m2 or about .45 hectares). An actual Landsat scan is 185 km wide so the study sheet is only a small portion of an entire Landsat scene. It has been shown that Landsat can yield timber management maps with about 90% accuracy compared to actual conditions on the Earth. The accuracy of the data from Landsat is checked by actually verifying the information with on-site inspections of the photographed area. This technique, called “ground truth”, is very important in developing interpretation skills for information gained when exploring other planets. This lesson allows students to experience some of the skills needed to interpret a computer generated map transmitted by the Landsat satellite. Additional information and experiences can be found in an excellent NASA publication, Mission to Earth: Landsat Views of the World, NASA SP-360.
Have the students work in pairs or individually. Reproduce the map on the study sheet for each group of students. Have the students determine what kind of information can be obtained from this type of map.
Tree canopy refers to the development of branches; the more closed the canopy, the larger and more mature are the trees. Open canopy indicates that more ground shows through the branches of younger, smaller trees. Clearcut refers to areas where all standing trees have been removed. You may wish to have the students color in the areas on the map to designate each category listed above.
- What is the total area represented by the map? Total area of hardwood? Soft wood?
- Which area is beginning to grow young trees? has young trees? has older, mature trees?
- How does the area which has been clear cut compare to the selectively cut area? the most recently harvested?
- Describe the advantages and disadvantages of both selective and clear cutting.
- What do you suppose are the areas for which the computer provided no classification? what may have caused this?
- What might be the value of these maps for timber managers, lumber companies and paper companies?
- How might such maps aid an environmental protection agency? A space scientist exploring other planets?
Computer generated map which illustrates the use of Landsat data in forest resource management. Illustration courtesy NASA