Purpose

In this activity, elevation data collected from a school site will be converted into a raster grid for analysis.

Materials

• A. Collecting School Site Data

• • Stakes and string
  • Meter sticks
  • Plumb line
  • Level
  • Pencil and paper

• A. Analysis of Data

• • Macintosh computer
  • Printer
  • ClarisWorks
  • NIH Image

Procedure

• A. Collecting School Data

• • 1. Each pair of students will be assigned a line to work in order to gather their data. The lines will be spaced at 1 meter intervals.
  • 2. From the start point, level 1 meter stick. Use the other meter stick to measure (in centimeters) the distance to the ground. Record this measurement on your data table.

  
  

  • 3. Move the meter stick and level to the other side of the vertical meter stick. Relevel it.

  
  

  • 4. Measure the distance from the forward end of the meter stick and level to the ground. Add this measurement to the previous measurement and record it on the data table.

  
  

  • 5. Measurements of elevation (in centimeters) should be made and recorded every meter along your assigned line. The level should be used to keep the meter stick as flat as possible. Do not use decimal or negative values, use whole number values only.

  
  

  • 6. Fill in elevation measurements on the data chart provided.

• B. Analysis of Data

• • 1. Add your elevation measurements to the class data recorded in the ClarisWorks word processing file. As you enter the data, type only the number of each elevation. Single space between each number as you enter it on the screen.

  
  

  • 2. After all the class data is entered in the "correct sequence", pull down the "File" menu and select "Save As", select "text" to save the information. Quit ClarisWorks.

  
  

  • 3. Open NIH Image, select "Import" from the "File" menu.

  
  

  • 4. From ClarisWorks, select the name of your file, then select "Edit". Set the "width" as the number of columns of data and "height" as the number of rows of data. Remember to select "Text" before you open your file.

  
  

  • 5. Click on the tiny icon (found next to the Tools heading). Then, from the "Options menu, select "Scale to Fit Window". Click and Drag on the lower right-hand corner of the "Small Icon" next to the "Tool Bar" to enlarge the image.

  
  

  • 6. The elevations are now plotted as a Raster Grid. They can now be displayed as a three-dimensional drawing. Select "Surface Plot" from the "Analyze" menu.

Discussion: Answer on your own paper. Use complete Sentences.

• 1. What, if any evidence, do you see on your class profile that one or more of the groups collecting elevation data at the school site made an error in their data?

• 2. Using the angle tool, where is the steepest slope on your school site profile? How does this help you explain water drainage on your site?

• 3. How could the tool for measuring be used to study this school site?