Paris in a Different Light
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite (http://modis.gsf
(http://modis.gsfc.nasa.gov/gallery/). c.nasa.gov/gallery/). The infrared image below is of Paris taken on July 23, 2000. The infrared image below is of Paris taken on July 23, 2000. TheThe famous Seine River snakes through the image from left to right, and appears black because water is famous Seine River snakes through the image from left to right, and appears black because water is colder than the surrounding landscape. Vegetation appears red
colder than the surrounding landscape. Vegetation appears red and buildings appear bland buildings appear blue-gray becauseue-gray because of the color-coding that was used to
of the color-coding that was used to represent warm (red) and cold (blue) areas.represent warm (red) and cold (blue) areas.
Problem 1
Problem 1- This image is 5.6 kilometers wide. Using a metric ruler, what is the scale of the- This image is 5.6 kilometers wide. Using a metric ruler, what is the scale of the
image in meters/mm? image in meters/mm?
Problem 2
Problem 2- What is - What is the width, the width, in meters, in meters, of; of; A) The Seine A) The Seine River? River? B) The traffic B) The traffic circle (Arccircle (Arc
de Triomphe) de Triomphe)
Problem 3
Problem 3- The shadow of the Eiffel Tower can be seen as the triangular spot between the- The shadow of the Eiffel Tower can be seen as the triangular spot between the
two arrows. Measure the length of the shadow indicated by the arrows, and from the solar two arrows. Measure the length of the shadow indicated by the arrows, and from the solar
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Answer Key
Answer Key
Problem 1
Problem 1 - This image is 5.6 kilometers wide. Using a metric ruler, what is the scale of- This image is 5.6 kilometers wide. Using a metric ruler, what is the scale of
the image in meters/mm?
the image in meters/mm? Answer: The width is 140 mm, so the scale is 5600/140 = 40Answer: The width is 140 mm, so the scale is 5600/140 = 40 meters/mm.
meters/mm.
Problem 2 - What is the width, in meters, of Problem 2 - What is the width, in meters, of A) the Seine River?
A) the Seine River? Answer: Answer: About About 5 5 mm mm or or 200 200 meters.meters. B) The traffic circle (Arc de
B) The traffic circle (Arc de Triomphe)Triomphe) Answer: About 7mm or 280 Answer: About 7mm or 280 meters.meters.
Problem 3
Problem 3 -- The shadow of the Eiffel Tower can be seen in this ASTER image as the triangularThe shadow of the Eiffel Tower can be seen in this ASTER image as the triangular
spot between the two arrows. Measure the length of the shadow indicated by the arrows, and spot between the two arrows. Measure the length of the shadow indicated by the arrows, and from the solar elevation angle of 60 degrees at the time of the photograph. Create a scaled from the solar elevation angle of 60 degrees at the time of the photograph. Create a scaled drawing of the tower, the shadow and the solar angle. A) From your drawing, what is the height of drawing of the tower, the shadow and the solar angle. A) From your drawing, what is the height of the Eiffel Tower in meters?
the Eiffel Tower in meters? B) At what sun angle would the shadow be 311 meters long?B) At what sun angle would the shadow be 311 meters long?
Answer: A) The sketch below gives this information. The length of the shadow is about 4.5 mm or
Answer: A) The sketch below gives this information. The length of the shadow is about 4.5 mm or
180 meters. Students may carefully draw a scaled triangle using 1cm = 10 meters, so that the
180 meters. Students may carefully draw a scaled triangle using 1cm = 10 meters, so that the
shadow (base of triangle) is 18cm long.
shadow (base of triangle) is 18cm long. The hypotenuse will then be 180m x (2) The hypotenuse will then be 180m x (2) = 360 meters or= 360 meters or
36 cm. The vertical side, which is the height of the Eiffel Tower will be 180 m x (3)1/2 = 180m x
36 cm. The vertical side, which is the height of the Eiffel Tower will be 180 m x (3)1/2 = 180m x
1.732 = 311 meters.
1.732 = 311 meters. The actual height of the Eiffel Tower is 300 metThe actual height of the Eiffel Tower is 300 meters to the roof and 320ers to the roof and 320
meters including the radio spire at its top, so the student's estimate from the shadow length is
meters including the radio spire at its top, so the student's estimate from the shadow length is
reasonably accurate, given the resolution of the photo.
reasonably accurate, given the resolution of the photo.
B)
B) Answer: If the height of tAnswer: If the height of the tower is the same as he tower is the same as the shadow length, the angle must the shadow length, the angle must be 45be 45
degrees.
degrees.
The photograph below shows a more familiar view of this historic structure. (Courtesy The photograph below shows a more familiar view of this historic structure. (Courtesy FreeDigitalPhotos.net)