Drawing Contour Lines

Mike Phillips, Illinois Valley Community College

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Summary

Formative assessment questions using a classroom response system ("clickers") can be used to reveal students' understanding of spot elevations and contour lines.

Students are shown this diagram and instructed to "Click where the 0 contour line (sea level) is located." The class discusses the results and is then asked to "Click where the 10 ft contour line is located." The distribution of student responses should resemble the contour line line (via heat map or connectable dots).

Learning Goals

Content/concept goals for this activity

Students will be able to interpolate the location of a contour line given a set of elevations.

Context for Use

Audience

This activity is used as a formative assessment in an introductory-level geoscience course.

The concept of elevation should be introduced and discussed prior to beginning the lab. Independently completed contour maps (typically included in lab manuals) would be an appropriately summative assessment.

How the activity is situated in the course

This activity is used as a formative assessment within a lab where students will draw a topographic contour map.

Description and Teaching Materials

Example of how to implement this exercise in the classroom

Display the attached map of elevation points (or a similar map) and ask students to click on a specific elevation and a contour line of that value (ie. 10ft or 20 ft). The resulting display of results will show multiple points across the map and illustrate the location of the contour line.

The class then answers for successively higher elevations at a selected contour interval, and discusses line placement and related topics such as contour intervals after each iteration. The clicker activity can stop when the answers displayed are in the appropriate location. Students can be provided with a paper copy of the map on which to record their answers and draw in the contour lines with the class; when the clicker portion concludes, students can be directed to complete the map and submit it for assessment.

With the top attached map, the class could answer for 0 (sea level), and then discuss the concept of sea level as a base elevation for contour maps. The class would then answer for successively higher elevations at a selected contour interval (10, 20, 30 etc.), and discuss contour intervals and line placement.


Response to the prompt "Click where the 10-foot contour line should be placed." is shown on the bottom attached map. The responses indicate that further discussion on line placement is needed.

Teaching Notes and Tips

  • The class will need to have access to software (e.g., a web-application) and hardware (e.g., a smart phone, tablet, etc.) that allows students to click on displayed imagery.
  • The exercise can be incorporated as part of a lab or class exercise on drawing topographic contour lines.
  • Discussion of elevation point placement and line drawing should take place after each iteration.
  • If answers cluster in one location, the instructor may need to encourage students to click across the map in order to approximate the position of a line.
  • There may be some confusion about where the points lie along the streams; this should be discussed with the class. (Contour lines typically make a V that points upstream because the stream is cutting down into the landscape.)

Assessment

The instructor should collect the completed maps at the end of the activity. The resulting assessment may be for points (participation or correctness). Feedback may be provided by displaying a correctly completed map or on individually graded papers.

References and Resources

This is based on a static on-line tutorial I created. Drawing Contour Lines

Search the Teach The Earth portal for "topographic maps" or "contour lines" for additional activities.