Introduction%20to%20Remote%20Sensing

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• Introduction to Remote Sensing
• Example Applications and Principles
• Exploring Images with MultiSpec
• User Interface and Band Combinations
• Questions

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Definitions

• Lillesand and Kiefer (1994) The science and
  art of obtaining information acquired by a
  device that is not in contact with the object
• CCRS Glossary A group of techniques for
  collecting image or other forms of data from
  measurements made at a distance from the object,
  and the processing and analysis of the data.

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Examples of Remotely Sensed Data

• Weather
• Ocean Properties
• Physical Geography
• Major Disturbance Events / Hazards
• Cultural Features urban mapping
• Many other examples thematic info

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disturbance
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Decision
From Lillesand and Kiefer (1994)
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Decision
From Lillesand and Kiefer (1994)
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An Electromagnetic Wave
l wavelength
c velocity of light
n frequency
From Lillesand Kiefer (1994)
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O3 absorption at 0.2 um
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H2O absorption at 1.4, 1.6, and 1.9 um
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CO2 absorption at 2.0 um
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CH4 absorption at 2.2 2.5 um
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Human eye
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E(l)i E(l)a E(l)t Er(l)
Incident Energy
Reflected Energy
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Atmospheric Interactions
Rayleigh Scattering
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Types of Satellite Orbits

• Geostationary 35,790 km above the Earth
• Sun-synchronous or Polar between 700 and 800
  km above the Earth

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Satellite Orbits
http//science.nasa.gov/Realtime/jtrack/3d/JTrack3
D.html
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Resolution in Remote Sensing

• Four types
• 1) Spatial the ground coverage / pixel
• 2) Spectral area and subdivision of the EM
  spectrum
• 3) Temporal frequency of coverage
• 4) Radiometric sensitivity to changes in
  energy intensity

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Issues of spatial temporal scale of the sensor
platform -SPATIAL- grain and extent Pixel
-TEMPORAL- Frequency of
imaging
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September 30
September 15
October 15
October 30
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Color Theory and Band Combinations

• Additive colors vs. Subtractive colors
• Natural and False color composites
• Displaying images, extracting information

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• Additive Primaries

No single primary can be formed by mixture of
other two All other colors can be formed by
mixtures of additives

• Subtractive Primaries

Representations of color via pigments and
dyes Yellow absorbs blue, cyan absorbs red,
magenta absorbs green
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Blue (0.45 um) Green (0.55 um) Red (0.65 um)
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Green 2.5 x
Red x
Blue x
Blue (0.45 um) Green (0.55 um) Red (0.65 um)
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Feb. 14, 2006 MODIS Terra, Eastern US
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Snow Vs. Clouds
Clouds scatterat all wavelengths
Snow absorbs at gt1.4 mm
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Snow Vs. Clouds
Clouds scatterat all wavelengths
Snow absorbs at gt1.4 mm
c
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Natural Color 3,2,1
Color IR 4,3,2
False Color 5,4,3
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MultiSpec RS Software

• Research and education
• Long period development and refinement
• Freely available
• Supported by tutorials
• http//cobweb.ecn.purdue.edu/biehl/MultiSpec/