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Remote Sensing #2--: Spectral Signatures

By: Ryan Swearingen

Estimated Sessions:Second day of a two day project

Grade level: 8thGrade Social Studies and high school Geography and History of the World

Purpose: Students will learn how to navigate and interpret remote sensing and spectral signatures.

National Geography Standards addressed:

1: he use of maps and other geographical representations! tools! and technologies to ac"uire! process! and report

information from a spatial perspective.

18: How to apply geography to interpret the present and plan for the future.

Indiana Social Studies cademic Indicators addressed:

Eighth Grade

8.#.1 Read a topographic map to interpret its sym$ols. %etermine the land forms and human features that represent

physical and cultural characteristics of areas in the &nites States.

8.#.11 &se of information technology! such as Geographic 'nformation Systems and remotely sensed images to

gather information on ways people have changed the physical environment of the &nited States in the 1(

th

century.

High School Geography and History of the World

).* +repare maps! timelines! and,or other graphic representations showing the origin and spread of specific

innovations. -ssess the impact of these innovations on the human and physical environments of the regions towhich they spread.

!"ectives: &pon completion of the activities! students will $e a$le to

1. discuss and eplain the different spectral signatures for dry $are soil! vegetation! and water!

*. identify and interpret color composite satellite images!

#. eplain reflectance values /%0 values!

2. identify and eplain spectral signatures $y reading graphs! and

3. classify satellite images $ased on their spectral signatures.

Bac$ground:

Students will have already completed activities 14# on the interactive we$site.

Students will also $e given a handout on the day $efore over spectral signatures. See attached.

%aterials Re&uired:

1. 5omputer la$ with internet access

*. Remote Sensing and 'nteractive We$site4 http:,,$a$y.indstate.esu,mvh,#. 5omputers networ6ed so that the instructor can monitor the answers

2. Handout over spectral signatures! attached at the end of this lesson plan

Procedures:1. Students go to 4http:,,$a$y.indstate.esu,mvh, and log into we$site.

*. Students will navigate through the we$site completing activity 2.

#. eacher will monitor the classroom and answer "uestions as needed.2. %iscuss the impact that geo4spatial technologies has on the lives of humans and on the 7arth. 'dentify ways in

which the technologies have diffused.

ssessment:

1. 'nstructor will monitor the students answers on the interactive we$site.

daptations'E(tensions')all-!ut:

1. his lesson could $e used in any secondary Geography class.

http://baby.indstate.esu/mvh/http://baby.indstate.esu/mvh/http://baby.indstate.esu/mvh/http://baby.indstate.esu/mvh/http://baby.indstate.esu/mvh/

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Resources:

http:,,$a$y.indstate.esu,mvh,

http:,,rst.gsfc.nasa.gov,

Bac$ground on Spectral Signatures

9or any given material! the amount of solar radiation that is reflected /a$sor$ed! transmitted will vary with

wavelength. his important property of matter allows us to separate distinct cover types $ased on their response

values for a given wavelength. When we plot the response characteristics of a certain cover type againstwavelength! we define what is termed thespectral signatureof that cover. he diagram $elow illustrates the

spectral signatures for some common cover types.

Generalied spectral signatures for some common cover types

;y comparing the response patterns of different features we may $e a$le to distinguish $etween them! where we

might not $e a$le to! if we only compared them at one wavelength. 9or eample! water and vegetation may reflect

somewhat similarly in the visi$le wavelengths $ut are almost always separa$le in the infrared. Spectral response

can $e "uite varia$le! even for the same target type! and can also vary with time /e.g.

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of the water $ody! then this will allow $etter reflectivity and a $righter appearance of the water. he apparent colour

of the water will show a slight shift to longer wavelengths. Suspended sediment /S can $e easily confused with

shallow /$ut clear water! since these two phenomena appear very similar. 5hlorophyll in algae a$sor$s more of the

$lue wavelengths and reflects the green! ma6ing the water appear more green in colour when algae is present. he

topography of the water surface /rough! smooth! floating materials! etc. can also lead to complications for water4

related interpretation due to potential pro$lems of specular reflection and other influences on colour and $rightness.

+egetation4 - chemical compound in leaves called chlorophyll strongly a$sor$s radiation in the red and $lue

wavelengths $ut reflects green wavelengths. ?eaves appear