Landscapes and

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Landscapes and
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100km
Detroit
Toledo
Cleveland
Pittsburgh
Columbus
Cincinnati
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ESR
Laboratory
Kent State University
Ohio DEM 30m Digital Elevation Model of Ohio.
Compiled and clipped from the National Elevation
Dataset
100km
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3-D Visualization of Landscapes
Digital Elevation Model of Downtown Cleveland
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WHY USE DIGITAL ELEVATION MODELS?

• DEMs display virtually no features that were made
  by humans

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What is a DEM (Digital Elevation Model)?
Files of elevation data with each pixel assigned
a height value
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What the numbers mean when converted to a DEM
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3
2
1
0
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Some satellites can measure heights on the ground
or even the sea

• Skylab
• Geos-3
• SeaSat
• GeoSat

• ERS-1
• Topex/Poseidon
• ERS-2

TOPEX
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What are DEMs used for?

• Monitoring glacial movement, growth, and decay
• Simulating river flow
• Determining how much of a landscape would be
  flooded if a dam was built
• Monitor Earth movements

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Damming What if the Grand Canyon was dammed
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700m
650m
800m
750m
1600m
900m
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Landsat 7 image of Cleveland and NASA Glenn
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DEM model of Cleveland and NASA Glenn
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Light occurs in different wavelengths
SHORTEST
LONGEST
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ADVANCE
RETREAT
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Courtesy of Chromadepth
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Courtesy of Chromadepth
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The Tibetan Plateau
Chromostereoscopy
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NASA Glenn
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Monitoring Change the eruption of Mount St.
Helens, May 18th, 1980
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1980 eruption of Mount St. Helens
Before the eruption
After the eruption