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Explore the science of remote sensing using satellite images, from spectral reflectance to spatial resolution. Learn about EMR, matter interactions, and different types of remote sensing. Discover how technology like Landsat MSS and SPOT satellites revolutionize environmental analysis.
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Remote Sensing of Our Environment Using Satellite Digital Images to Analyze the Earth’s Surface
Definition of Remote Sensing • Remote sensing is the science and art of acquiring information (spectral, spatial, temporal) about material objects, area, or phenomenon, without coming into physical contact.
EMR • In remote sensing, information transfer is accomplished by use of electromagnetic radiation (EMR).
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
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
Spectral Reflectance of Land Covers Spectral reflectance of vegetation, soil and water
Spectral Reflectance of Land Covers Spectral reflectance of different kinds of trees
Resolution • Spectral Resolution • Radiometric Resolution • Spatial Resolution • Temporal Resolution
Landsat MSS • Spectral Resolution • 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
Landsat MSS • Orbital altitude – 570 miles • 11.560 FOV – 115 mile swath
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.
SPOT • Orbital altitude – 516 miles • 73 mile swath
Commercialization of Space Remote Sensing Here is a SpaceImaging high resolution panchromatic scene that shows the pyramids outside of Cairo, Egypt
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.
IKONOS • 1999 launch • Spatial Resolution: • B/W: 82-cm • Multispectral: 4-meter
IKONOS • Spectral Range • 526–929 nm445–516 nm (blue)506–595 nm (green)632–698 nm (red)757–853 nm (near IR) • Revisit Time • Approximately 3 days