The purpose of this resource is to familiarize students with modeling as it relates to remote sensing and digitized images. Students will use the symbolic map created in the beginning activity to produce a digitized image and begin to see why ground verification of satellite data is necessary. Educational levels: Middle school, High school

The GLOBE Program, University Corporation for Atmospheric Research (UCAR)

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Digital Library for Earth System Education

GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 1 Land Cover/Biology
A
ppendix
W
elcom
e
Introduction
Protocols
Learning A
ctivities
!
?Odyssey of the Eyes  
Intermediate Level
Purpose
To familiarize students with the concept of 
modeling as it is related to remote sensing and 
to the process of digitizing images. 
Overview
Students will use the symbolic map created in 
the beginning activity to produce a digitized 
image.  As they perform the activity, they will 
begin to see why ground verification of satellite 
data is necessary in order for scientists to create 
accurate models of the Earth’s systems.
Student Outcomes
Science Content
Science and Technology
Scientists rely on technology to enhance 
the gathering and manipulation of data.
Science as Inquiry
Communications involves coding and 
decoding.
Tables, graphs and symbols are alternative 
ways of representing data.
Use numerical data in describing and 
comparing objects and events.
Geography
Primary
Maps and satellite-produced images
Middle
Characteristics, functions, and applications 
of maps, globes, satellite images
Enrichment 
Objects in a remotely sensed image are 
interpreted and digitized into a code 
based upon the object’s reflectance of 
bands of light.
The image codes are relayed through a 
satellite dish to a computer for storage 
or enhancement.
Image display is accomplished by 
conversion of stored data to a user-
defined color-coded image.
Scientific Inquiry Abilities
Observe, digitize and interpret an image.
Level
Middle
Time 
Two to three class periods
Materials and Tools 
    Graph paper
Pencils
Maps and models from Odyssey of the Eyes 
Beginning Level
Plastic overlay with Odyssey of the Eyes Grid 
Colored pencils
Odyssey of the Eyes Digitized Data Sheet
Preparation
Assemble the materials.
Demonstrate the process of digitizing to the class 
before you have students work with partners.
Prerequisites
Students should know how satellites receive 
information and relay it to a computer. 
Odyssey of the Eyes Beginning Level is necessary 
for the completion of this activity. 
Note: This activity presents concepts similar to 
those in steps 8, 9, and 10 of the Relative and 
Absolute Directions Learning Activity in the GPS 
Investigation. 
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 2 Land Cover/Biology
Background
The sun emits energy in the form of light. This light 
energy reaches the earth. The light is composed 
of many bands of light, including visible light. 
Visible light is made up of red, orange, yellow, 
green, blue, indigo, and violet. Each object on 
earth reflects visible light differently. Some objects 
reflect all visible light (objects that appear white 
to us), others absorb all visible light (objects that 
appear black to us), and some reflect different 
amounts for each band of visible light. Satellites 
record the amount of light reflected from objects 
on the ground. They store this information as data 
or code. These codes or data are visualized on a 
computer and called satellite images. 
What To Do and How To Do It
Part 1: How Digitized Images Are Made
Students will learn how satellites and computers 
communicate with each other. One student will 
serve as the satellite and the other will represent 
the computer. Using a black and white picture, the 
student “satellite” will scan a picture, translating 
it into a digitized code. The student “computer” 
will translate the numeric code, reproducing the 
image.
1.  Students work in pairs. One serves as 
the satellite and the other represents the 
computer. The satellite places the plastic 
overlay with the Odyssey of the Eyes Grid 
over the black and white picture of the 
Odyssey of the Eyes Satellite. The satellite 
scans the picture, one box at a time, 
starting at the left-hand corner of the 
picture. The satellite calls out a number 
code for each box on the grid to his or her 
computer (partner). The computer writes 
the number code on their grid.
2.  The satellite will interpret each square 
according to the following guidelines:
 • The satellite indicates the beginning  
 and end of each scan line with a “0.”
 • If a box is white: the satellite interprets  
 the message as a “1.”
 • If a box is gray: the satellite interprets  
 the message as a “2.” 
 • If a box is black: the satellite interprets  
 the message as a “3.” 
 • If a box is not all black, all gray or all  
 white: the satellite must make a  
  decision as to the best possible 
choice,   “1”, “2” or “3.”  The 
“satellite” should   make his 
decision based on whether the   
square is mostly black, gray, or white.
3.  Using a pencil, the student representing 
the computer translates the digital code 
onto the graph paper, creating a satellite 
image. They begin or end a line when they 
read a “0,” leave a box blank when they 
read a “1,” and shade in the square lightly 
if they read a “2” or shade in the square 
black, if they read a “3.” 
Example:
If the boxes in the first row are white, white, black, 
mostly black, and gray and the second row is 
white, gray, black, mostly white, and gray; the “sat-
ellite” would translates this to [01133200123120]. 
The computer writes down this code and then 
colors in the grid of the first row with white, white, 
black, black, gray and the second row with white, 
gray, black, white, gray.
Note: For additional practice, use student gener-
ated color pictures and different size grids.
Part 2: Making a Digitized Image Using 
Data From a Map Model
1.  Supply each group with a plastic grid 
overlay (made from the Odyssey of the Eyes 
Grid). Have the students place this grid 
over the symbolic map from Odyssey of the 
Eyes Beginning Level. 
2.  Ask students to create a color and number 
code (key or legend) for the land cover 
items on their map. Assign each landform 
on the symbolic map a color and a 
number. Record this on the Odyssey of the 
Eyes Digitized Data Sheet. 
3. Ask students to create the digitized code 
for their map: 
 • Begin and end each scan line with a “0.” 
 • Scan each line of the symbolic map,  
 “coding” each square with a number  
 determined by the Odyssey of the Eyes  
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 3 Land Cover/Biology
A
ppendix
W
elcom
e
Introduction
Protocols
Learning A
ctivities
 Digitized Data Sheet. 
 • Record the numbers on the data chart. 
 • Review the guidelines in Part One of  
 this activity for further assistance. 
4. Finally, using the digitized code, ask 
students to select the matching colors and 
reproduce the map as a digitized image on 
a piece of graph paper.
Discussion and Assessment
1. Look at your symbolic map. 
 a. What is different about the digitized  
 map or image? 
 b. What is the same?
 c. Do you think that the image and model  
 both represent the same amount of each  
 land cover type or landform?
2. Look at your original model.
 a. What is different about the digitized  
 map or image? 
 b. What is the same?
 c. Do you think that the image and model  
 both represent the same amount of each  
 land cover types or landform?
 d. Look at the symbolic map. Look for  
 differences and similarities between the  
 symbolic map and original model. Can  
 you name two of each?
3. Compare and contrast maps produced by 
other groups:
 a. How do you know the maps are  
  accurate? 
 b. What happens to land cover types that  
 are a small size when you draw a  
 symbolic map or digitize an image? 
 c. What happens to land cover types that  
 have irregular shapes?
 d. How do these changes affect what type  
 and amount of land cover you see?
4. What function does the satellite perform 
when mapping?
5 What function does the computer perform 
when mapping?
6. Why are maps from one group of students 
different than maps from another group?
7. Do the colors chosen to represent each 
type of land cover have to reflect what you 
see on the ground?
8. How would digitizing your model be 
different if the model were illuminated 
under blue light?
Note: Ground verification is what you are doing 
in some of the Land Cover/Biology Protocols. In the 
Land Cover Sample Site Protocol, students verify 
what is actually on the ground compared to what 
is interpreted by a satellite image or a model.
Extension
The Landsat satellite collects the data for your 
GLOBE Study Site. Label the parts of the Land-
sat satellite and describe what each part does. 
For diagrams and information about Landsat, 
see the Land Cover/ Biology GLOBE Web site at  
http://www.globe.unh.edu  
or the Landsat NASA Web site at  
http://geo.arc.nasa.gov/sge/landsat/landsat.html
Acknowledgment
Satellite art by Sherri Wormstead
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 4 Land Cover/Biology
Odyssey of the Eyes Large Grid
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 5 Land Cover/Biology
Odyssey of the Eyes Small Grid
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 6 Land Cover/Biology
GLOBE® 2005 Odyssey of the Eyes: Intermediate Learning Activity - 7 Land Cover/Biology
Land Cover Type Symbol Number Digitizing Color
Example: Road
Example: Tree
1
2
Black
Green
Odyssey of the Eyes
 Digitized Data Sheet
Name: _____________________________________Date: ________________________________________  
Digitized Code
Use a 0 to indicate the beginning and ending of each scan line.
For the large-sized grid squares, use the following lines as an example of how to set-up 
your paper.           
           0 ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ 0
0 ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____  0
For the small-sized grid squares, use the following lines as an example of how to set-
up your paper.  
0 ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ 0
0 ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ 0


Odyssey of the Eyes Intermediate Level

http://www.globe.gov/tctg/land_la_eyesint.pdf?sectionId=222

Odyssey of the Eyes Intermediate Level

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