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Measure the Reflection of Land Covers

Jump to: [materials]  [what to do]

Use your tools to see what the Landsat sensors see from 920 km above the Earth.

Materials

  • One Red, Green, and Near Infrared (IR) LED 

  • Voltmeter or multimeter with clips 
  • Access to outdoors with pavement, grass, dirt, and water. 
  • Additional land covers include snow, ice, and sand, but are seasonal/geographically limited.

What to Do...

  1. Go outside with your instruments, preferably on a sunny to partly cloudy day.

    Landsat image of eastern Massachusetts and  Rhode Island.
  2. Measure the intensity of the sunlight by pointing the LED toward the Sun. Do not look directly at the Sun while doing this.

  3. Estimate your pointing by either

    • watching the voltage and move the LED to find the maximum value, or

    • looking at the shadow of the LED on the ground—the smallest shadow of LED will mean it’s pointing directly at Sun.

  4. Point your LED at the ground and record the voltage and the surface type. If you have a partly cloudy sky, continue to measure the intensity of sun light before each measurement.

  5. Measure a variety of surfaces. Record your observations and measurements in a table like the one below.


Surface
Voltage of RED LED from Sun
Voltage of RED LED from Reflected Light
Reflected RED Light [%]
Voltage of GREEN LED from Sun
Voltage of GREEN LED from Reflected Light
Reflected GREEN Light [%]
Voltage of IR LED from Sun
Voltage of IR LED from Reflected Light
Reflected IR Light [%]
Grassy field                  
Pond                  
Dirt                  
Concrete sidewalk                  


Relate Your Data to Landsat Images