SUPPORT

Student reflection activity:

  • Prompt students to think about the process and elements for evaluating the state of coral reefs in remote sensing data images.
  • Prompt students to record how they analyzed the remote sensing images for evaluating the state of coral reefs in Kailua Bay.
  • Prompt students to think about why they need to have classification maps and pie charts for evaluating the state of coral reefs of Kailua Bay.
  • Prompt students to think about which data images are required to evaluate whether there has been a change in the state of coral reefs in Kailua Bay.

Assessment:

  • Students differentiate between DMSV images, AVIRIS image, and Landsat images.
  • Students define the classification scheme that they will use for the KaAMS mission.
  • Students decide the classification categories of ground truthing photographs.
  • Student investigate the changes of the state of coral reefs in Kailua Bay.

Ideas for math lesson connections

  • Students create a chart which compares the information gathered from classification images of the coral reefs.

Related National Education Math Standards

Ideas for geography lesson connections

  • Students learn how to read classification maps and practice skills by examining a classification map.
  • Students apply the information learned from the classification map to interpret the present and plan for the future of the region surrounding Kilauea.

Related National Education Geography Standards

Ideas for technology lesson connections

  • Word processing: Students create their own electronic journal for keeping notes on KaAMS project.
  • Database: Students create a database of vocabulary words and terms they will learn throughout KaAMS.
  • Graphics: Students create pictures of Hawaiian Islands, remote sensing missions, aeronautics.
  • Presentation software: Students create a short presentation on their understanding of airborne remote sensing.
  • Web development: Students begin to develop a web-site to report their progress and what they learn during the KaAMS project.

Related National Education Science Technology Standards

Activity sheet: Watching over our planet from space (AI-1)

Name: ____________________________________________________________

1. Activity name ______________________

Find It!

2. Briefly describe the activity you completed:

In this activity we used number coordinates to find different features in a Landsat satellite image

3. What objects and/or features did you observe in the images in your activity?

Roads, farmland, rivers, vegetation, lakes, islands, ponds

4. Why are these images important? (What did they tell you?)

This image could be used to investigate land use, crop health, and ecological and geographical studies.

 

Teacher Answer Keys for the activities from Watching over our planet from space

 

3.1 Which is Which ?

a) 2 b) 7 c) 12 d) 9 e) 8 f) 10 g) 5 h) 10 i) 4 j) 11 k) 3 l) 6 m) 1

3.2 Find It

1) C: (7.7, 6.1) 2) A: (5.2, 2.6) 3) B: (4.8, 6.7) 4) A: (8.2, 4.2)

5) D: (5.7, 8.0) 6) B: (5.5, 6.4) 7) D: (5.3, 5.0)

3.3a Measure This

(northern Saskatchewan)

1) D: (2.0, 0.5) 2) A: light pink 3) C: less than 1 km long

4) A: 17 km 5) B: less than 1 square km 6) D: 10 km

3.7 Forest Fire

Task #1 Approximately 16 km

Task #2 Closest Lake is at: (2.1, 2.1). Next closest lake is at: (0.7, 3.7)

3.8 At a Mine Site

1)(4.5, 2.7) 2) (2.0, 6.0) 3) (6.5, 6.7) 4) (4.6, 3.2)

5) (3.7, 3.7) 6) (6.5, 8.1) 7)(4.1, 8.8)

 

Activity sheet: Summary (AI-2)


 
1. What is the difference between visible and infrared images?

The light, which our eyes - our "remote sensors" - can detect is part of the visible spectrum. It is important to recognize how small the visible portion is relative to the rest of the spectrum. Therefore visible images are essentially images of what our eyes would detect.  The visible wavelengths cover a range from approximately 0.4 to 0.7 mm. 

 There is a lot of radiation around us, which is "invisible" to our eyes (i.e. infrared radiation), but can be detected by other remote sensing instruments and used to our advantage.  The infrared wavelengths cover a range from approximately 0.7 to 100 mm.

Reference:

http://www.ccrs.nrcan.gc.ca/ccrs/learn/tutorials/fundam/chapter1/chapter1_3_e.html

2. Why are colors in infrared images different from those in visible images?

Visible radiation is the only portion of the spectrum we can associate with the concept of colors.  Therefore, they are sometimes referred to as true-color images. Visible images are essentially a representation of what our eyes see. Infrared images cannot be seen with our eyes but must be detected by certain remote sensing instruments.  Colors in an infrared image do not correspond to anything our eyes detect.  Therefore, they are sometimes referred to as false-color images.

To see how color images are created refer to:

http://satftp.soest.hawaii.edu/space/hawaii/vfts/oahu/rem_sens_ex/rsex.spectral.3.html

 

Activity Sheet: Exploring the state of coral reefs with ground truthing photographs (AI-3)

1. What is your mission?

To write a recommendation based on the evaluation of the state of coral reefs in Kailua Bay.

2. Where is the study area?

Kailua Bay

3. Evaluate the eight detailed coral reef images and determine whether they are healthy. Write why you believe this is so.

Image
Are coral reefs healthy in this area?
Why?
1
Yes
 There is complete coral cover.
2
Not sure
 There is a coral surrounded by low-lying algae and sand.
3
No
 There is a sand.
4
Yes
 There is compete coral cover.
5
Not sure
 There is a coral surrounded by low-lying algae and sand.
6
Yes
 There is complete coral cover.
7
No
There is a sand and fossil reefs.
8
Medium
The image show that there are half sand and half coral reef.

4. Write a conclusion about the state of coral reefs in Kailua Bay.

The coral reefs of Kailua Bay look healthy overall. However we are still not sure because we don't have any criteria to evaluate the state of coral reefs.

 

Why do we need classification maps for each image set?

Sometimes geologists are interested in not only mapping large scale features on land but things hidden to the naked eye such as minerals that are present in rocks on the earth surface. Or in this case since we are studying a coral reef, we may be interested in the make-up of the reef--like the percent living coral cover or the different coral species on the ocean floor. Such information about the chemical or biological make-up of the coral reef cannot be determined just by looking at the color images of the AVIRIS, Landsat or DMSV sensors.

To extract "hidden" information from the data we use classification techniques. Classification clusters pixels (i.e. make classes or categories) based on digital/numerical data "inherent" in the remote sensing images. Rocks with a high iron content give off specific reflectance signals different than rocks high in silica, for example. So we can use their different reflectance signals to cluster the different rock types into categories.

To keep our classification simple, we have not tried to extract detailed information about the different type of algae or coral species. Instead we have clustered the ocean bottom reflectance into 4, easy to work with discrete classes.

For the classification scheme we use in this study, we have four categories:

  1. Category 1: Sand (or 0 % living coral)
  2. Category 2: 0 - 25% living coral
  3. Category 3: 25% - 75% living coral
  4. Category 4: >75% living coral (i.e. 75% - 100% living coral.)

 

Activity Sheet: Deciding the classification categories for ground truthing photographs (AI-4)

1. Where will each ground truthing photograph be placed in each of the four different categories? Write the image number in the second column.

Categories
Images
Why?
Sand and fossil reef category

3 and 7

 
  • The ground-truth pictures 3 and 7 (the sand part of the photograph) are examples of ocean bottom-types that would fit into this category. There is no ground-truth photograph of a fossil reef bottom. However, it looks like white colored cement on the ocean floor.
0-25% living coral category
5 and 2
  • The ground-truth picture 5 would be an example of a habitat that would fit in this category. In this image, there is one coral colony surrounded by low-lying algae and sand.
  • Ground-truth picture 2 would also fit in this category. This is a picture of green algae surrounded by sand. When divers dove in this area of the coral reef, they found the ocean floor covered with fields of this type of algae.
25%-75% living coral category
8
  • This category has a medium amount of living coral. Ground-truth picture 8 is an example of a habitat that would fall into this living coral category. As you can see from the picture this habitat is about half sand (in what is described as a "groove") and half coral reef (growing on what is described as a "spur").
75% living coral category
1, 4, and 6
  • Ground-truth pictures 1, 4 and 6 are examples of habitat the fit into this 75% living coral category. Although these habitats look different, they both have very complete coral cover over the ocean floor.
  • In ground-truth picture 1, there is a lush coral garden with all the coral colonies of about the same size. The larger coral colonies in this photograph grow in a form called "mounds" while the smaller, low-lying coral grow in a form called "encrusting". There are no "sand fields" or "grooves" filled with sand in this coral habitat, just total coral cover.
  • The habitat in ground-truth picture 4 also exhibits complete coral cover. This type of coral grows in a different form than those in the habitat in ground-truth picture 1. These corals are "branching" corals.
  • In ground-truth picture 6, there is also complete coral cover. However, in this habitat, one coral colony is much larger than the rest standing about 3 meters high. This sort of coral colony is called a "bomb". All around the "bomb," lower-lying coral grow completely covering the ocean floor.

2. Write a conclusion about the state of coral reefs in Kailua Bay based on above stated categories.

Based on the total percent area occupied by "percent living coral categories", it looks like there is an overall decrease in area covered by living coral.

 

Activity Sheet: Investigating the changes in the state of
coral reefs in Kailua Bay in the past years (AI-5A)

1. Write the percentages and the areas covered by various categories in the study area.

Table 1.

Data Type Date Sand and Fossil Reef 0-25% Living Coral 25-75% Living Coral >75% Living Coral
    Percent Area (m2) Percent Area (m2) Percent Area (m2) Percent Area (m2)
DMSV Jan/10/98 40 1,646,072 15 617,916 22 893,521 23 924,777
Landsat Feb./12/00 48 2,036,015 10 400,109 13 558,339 29 1,233,737
AVIRIS Apr./12/00 44 1,834,006 16 665,460 10 399,700 18 740,740

 

2. Comparing the state of coral reefs between January, 1998 and February, 2000.

1) Can you compare two these images? If so, which and why?

We can more reliably compare the DMSV data with the Landsat data sets because these data sets were collected on clear days, when there were no clouds over our study area and no obstructive ocean waves.

If you answered Yes to the question 1, please answer the following questions 2 to 4.

If you answered No to the question 1, please skip the answer the following questions 2 to 4.

2) Which categories were increased from 1998 to year 2000?
  • The sand and fossil reef category has increased from 40% to 48% in this time. At first this looked like there was a net loss in living coral reef of 8 percent.
  • Looking at the individual living coral categories, there was an increase in the >75% living coral category from 23% of the study area in 1998 to 29% in 2000.
3) Which categories were decreased from 1998 year to 2000 year?
  • There was also a decrease in the other two living coral categories. The 0-25% living coral category was reduced from an area of 15% of the total area in 1998 to 10% in 2000. The 25%-75% living coral category had reduced from 22% in 1998 to 13% in 2000.

4) What is your conclusion about the changes since 1998?

  • The total percent area occupied by "percent living coral categories" from Table 1 is 60% in 1998 (23%: >75% living coral + 22%: 25%-75% living coral + 15%: 0-25% living coral) and 52% in 2000 (29%: >75% living coral + 13%: 25%-75% living coral + 10%: 0-25% living coral). This looks like there is an overall decrease in area covered by living coral. However, since these categories are "ranges" of living coral, let us find the upper and lower extents of the live coral in these categories.
  • We were still concerned about the increase in area for the sand and fossil reef category. Did this mean that was an 8 percent loss of coral reef? To answer this question, we looked more closely at the percent living coral categories to find the range of living coral from the percentages in each category (Table 2).

    Table 2. Range of percent area covered by living coral.

Category
1998
2000
>75%
0.23(0.75-1.00)= 17 - 23%
0.29(0.75-1.00) = 22 - 29%
25% - 75%
0.22(0.25-0.75) = 6 - 17%
0.13(0.25-0.75) = 3 - 10%
0 - 25%
0.15(0.00-0.25) = 0 - 4%

0.10(0.00-0.25) = 0 - 3%
Total range of coral cover
23% - 44%
25%-42%
  • From the results in Table 2, it is less convincing that there has been a decrease in the area of living coral reef. While there is a 2% increase in the upper limit of living coral from 44% in 1998 to 42% in 2000, there has also been a 2% increase in the lower limit of live coral from 23% in 1998 to 25% in 2000. With a range of living coral on the order of 20%, a 2% difference is not significant enough to say that there has been loss of living coral reef.

 

3. Comparing the state of coral reefs from February, 2000 to April, 2000.

1) Can you compare two images? If then, why do you think so?

The AVIRIS (April 12th, 2000) image has clouds and cloud shadows in it. Due the clouds and shadows the percent living coral categories in this image are not very accurate because some of the reef is covered. It will be better to collect another AVIRIS data set without clouds and cloud shadows in it. Furthermore, there are waves on the surface of the ocean. Again, the data will be more reliable if collected on a day when the ocean surface is smoother.

2) Which categories were increased from February, 2000 year to April 2000 year?

  • There was also a increase in 0-25% living coral categories.

3) Which categories were decreased from February, 2000 year to April, 2000 year?

  • The sand and fossil reef category has decreased from 48% to 40% in this time.
  • There was also a decrease in the other two living coral categories. The 25-75% living coral category was reduced from an area of 13% of the total area to 10%. The >75% living coral category had reduced from 29% in 1998 to 18% in 2000

4) What is your conclusion of the changes in this time?

  • We can't draw our conclusions with these images. The AVIRIS (April 12th, 2000) image has clouds and cloud shadows in it. Due the clouds and shadows, the percent living coral categories in this image are not very accurate. It will be better to collect another AVIRIS data set without clouds and cloud shadows in it and draw the conclusions with those images.

 

rev October 12, 2002