Transcript Remote Sensing of Our Environment

Remote Sensing of Our
Environment
Using Satellite Digital Images to
Analyze the Earth’s Surface
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Remote Sensing Definition
• Remote sensing is the small- or large-scale
acquisition of information of an object or
phenomenon, by the use of either recording
or real-time sensing device(s) that are
wireless, or not in physical or intimate
contact with the object.
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Remote Sensing Definition (cont)
• In practice, remote sensing is the stand-off
collection through the use of a variety of
devices for gathering information on a
given object or area. Examples include:
• Aircraft
 PET
• Spacecraft
 X-Ray
• Ships
 Space Probes
• MRI

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Remote Sensing
• Remote sensing makes it possible to collect
data on dangerous or inaccessible areas.
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Data Acquisition Techniques
• There are two main types of remote sensing:
– passive remote sensing and
– active remote sensing.
• Passive sensors detect natural radiation that
is emitted or reflected by the object or
surrounding area being observed.
• Active sensors emit energy at an object and
records the energy reflected back to the
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sensor
Wavelength Units of
Measurements
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CIR Film at Close Range
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Air Photos
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Artist’s Rendition of SPOT
Satellite
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EMR
• In remote sensing, information
transfer is accomplished by use of
electromagnetic radiation (EMR).
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Electromagnetic Radiation
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Electromagnetic
Spectrum
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Geraniums - Normal Color Film
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Geraniums - CIR Film
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Normal Color/CIR Comparison
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Thermal Radiometer
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Archeology Site - South Dakota
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Big Brother Watching…..
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Interactions between Matter and
Electro-magnetic Radiation
• All matter reflects, absorbs, penetrates and
emits electro-magnetic radiation in a unique
way.
• For example, the reason why a leaf looks
green is that the chlorophyll absorbs blue
and red spectra and reflects the green
spectrum
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Types of Remote Sensing with
Respect to Wavelength Regions
• Remote sensing is classified into three types
with respect to the wavelength regions;
– (1)Visible and Reflective Infrared Remote
Sensing,
– (2)Thermal Infrared Remote Sensing and
– (3)Microwave Remote Sensing
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Spectral Reflectance of Land Covers
Spectral reflectance of vegetation, soil
and water
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Spectral Signatures
At what one
wavelength
does there
appear to be
maximum
separability?
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Spectral Reflectance of Land Covers
Spectral reflectance of different
kinds of trees
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Landsat MSS - Where??
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Where?
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Where?
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Where?
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Where?
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Gemini Film Image
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What Season?
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See the Line?
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Significant Variations in Land
Cover and Land Use
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Ready to Go!
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What Scale?
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MSS vs. TM
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SPOT - Washington DC
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Pacman Farm….
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Gharb, Morocco
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Gharb - Pre-Harvest
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Gharb - Post-Harvest
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Sakur, Japan
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Chernobyl - 1986
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Ocean Measurements
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California Mosaic
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Resolution
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Spectral Resolution
Radiometric Resolution
Spatial Resolution
Temporal Resolution
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Landsat MSS
• Spectral Resolution
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Band 4 (0.5 – 0.6 um, green)
Band 5 (0.6 – 0.7 um, red)
Band 6 (0.7 – 0.8 um, photo IR)
Band 7 (0.8 – 1.1um, near IR)
• Radiometric Resolution
– 1 byte (256 levels (0 – 255))
• Spatial Resolution
– 80m (260ft)
• Temporal Resolution
– 16 days
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Landsat MSS
• Orbital altitude – 570 miles
• 11.560 FOV – 115 mile swath
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SPOT
• Spectral Resolution
– Band 1 (0.50 – 0.59 um, green)
– Band 2 (0.60 – 0.68um, red)
– Band 3 (0.79 – 0.89um, RIR)
• Radiometric Resolution
– 1 byte
• Spatial Resolution
– 20m
• Temporal Resolution
– 26 days vertically downward. Can move mirror 270, increasing
repeatability to 7x in 26 days.
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SPOT
• Orbital altitude – 516 miles
• 73 mile swath
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Commercialization of Space Remote
Sensing
Here is a SpaceImaging
high resolution
panchromatic scene that
shows the pyramids outside
of Cairo, Egypt
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Quickbird-2 is the flagship of Digital Globe
The Pentagon (a year after it
was damaged by a terrorist
air assault) on the Virginia
side of the Potomac River
outside Washington, D.C.
2.8m spatial resolution.
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IKONOS
• 1999 launch
• Spatial Resolution:
– B/W: 82-cm
– Multispectral: 4-meter
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IKONOS
• Spectral Range
– 526–929 nm
445–516 nm (blue)
506–595 nm (green)
632–698 nm (red)
757–853 nm (near IR)
• Revisit Time
– Approximately 3 days
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GeoEye-1 and IKONOS
Comparison
Satellite Feature
GeoEye-1
IKONOS
Panchromatic Resolution
.5-meter
1-meter
Multispectral Resolution
1.64-meter
3.28-meter
Spectral Range
R G B IR
R G B IR
Launch Date
9/6/08
9/24/99
Orbit Altitude
681-km/423-miles
681-km/423/miles
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GeoEye-1: Ayers Rock
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GeoEye-1: Canyonlands, Utah
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GeoEye-1: El Capitan
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GeoEye-1: Kenai Fjords National Park,
Alaska
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GeoEye-1: The Moon
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GeoEye-1: Niagara Falls
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GeoEye-1: Rainbow Bridge, Utah
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GeoEye-1: Nile River Delta
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GeoEye-1: Burning Man 2009
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GeoEye-1: Burning Man 2009
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GeoEye-1: Sand & Gravel Plant
Arkansas
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GeoEye-1: Sand & Gravel Plant
Arkansas
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Aster: Yukon Delta
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Military Intelligence Satellites
The KH-12 series, the last for
which some specifications can
be found, is reputed to achieve
a resolution of 2+ cm, although
images of this sharpness haven't
been released.
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US Spy Imagery Sources
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U-2
SR-71
TARPS (Tactical Airborne Reconnaissance Pod System)
ATARS (Advanced Tactical Airborne Reconnaissance
System)
Predator UAV TESAR (Synthetic Aperture Radar)
Predator UAV Electro-optical
KH-4 CORONA
KH-5 ARGON
KH-11 KENNAN/CRYSTAL
KH-12 IMPROVED CRYSTAL
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Spatial Resolution
Detection vs.Recognition
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NYC Landsat TM
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Landsat 5
NYC
(summer 1997)
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ASTER: NYC - 9/22/02
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Digital Images
Colors present are additive mixes of
two or more primaries (e.g., yellow is
a mix of red and green; orange is a
mix of more red and some green;
white is an equal mix of all three
primaries, and black is simply the
absence of any colored light of any
wavelength). The colors that result
from combinations of blue, green,
and red (the primaries) are indicated
in this additive color diagram.
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NY Area Landsat MSS
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NY Area Landsat MSS
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Digital Image Construction
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