introduction of satellite remote sensing

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Introduction of Satellite Remote Sensing

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Spatial Resolution(Pixel size)

Spectral Resolution(Bands)

1. Spatial (what area and how detailed)

2. Spectral (what colors – bands)

3. Temporal (time of day/season/year)

4. Radiometric (color depth)

Resolutions of Remote Sensing

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The ability to resolve, or separate, small details is one way of describing what we call spatial resolution. Spatial resolution of images acquired by satellite sensor systems is usually expressed in meters.

For example, we often speak of Landsat as having “30-meter" spatial resolution, which means that two objects, thirty meters long or wide, sitting side by side, can be separated (resolved) on a Landsat image.

Other sensors have lower or higher spatial resolutions.

Landsat represents the world's longest continuously acquired collection of space-based land remote sensing data. It is considered the unique national assets.

The first Landsat satellite was launched in 1972; the most recent, Landsat 7, was launched on April 15, 1999.

The instruments on the Landsat satellites have acquired millionsof images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, geology, forestry, regional planning, education andnational security.

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Landsat MissionsLandsat 1 (07/12/1972 - 01/06/1978) - RBV, MSS (80m)Landsat 2 (01/22/1975-07/27/1983) - RBV, MSS (80m)Landsat 3 (03/05/1978-09/07/1983) - RBV, MSS (80m)

Landsat 4 (07/16/1982 - ) - MSS, TM (30m, 120m TIR)Landsat 5 (03/01/1984 - ) - MSS, TM (30m, 120m TIR)

Landsat 6 (10/05/1993): ETM

Landsat 7 (04/23/1999 - ) - ETM+ (30m, 60m TIR, 15m Pan)

Landsat Data Continuity Mission (LDCM) 2010 ....??????

MSS: Multispectral ScannerTM: Thematic MapperETM+: Enhanced Thematic Mapper PlusPan: PanchromaticTIR: Thermal InfraredRBV: Return Beam Vidicon Camera

August 17, 2007, The Office of Science and Technology Policy (OSTP) released the National Land Imaging Program (NLIP) strategy.

This program is designed to meet U.S. civilian moderate resolution land imaging needs to monitor the changes in land surface, Polar Regions, and coastal zones due to the changes in population growth, development and climate changes.

It establishes a program office in the Department of the Interior, reporting at the Secretary and Assistant Secretary level, to provide focused leadership and management for the nation’s land imaging efforts.

NLIP will focus on maintaining a core, operational government commitment and capability to collect moderate-resolution land imagery through the procurement and launch of a series of U.S. owned satellites thereby ensuring the continuity of U.S. collected and managed Landsat-like data, well into future decades.

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Landsat Multispectral

Scanner (MSS) and Landsat

Thematic Mapper (TM) Sensor System Characteristics

Landsat Multispectral

Scanner (MSS) and Landsat

Thematic Mapper (TM) Sensor System Characteristics

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Rhode Island: Path 12/Row 31

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Rhode Island: Path 12/Row 31

Landsat Ground Stations

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Landsat Images of the World

Ground resolution:1-meter panchromatic (0.45-0.90 µm), 4-meter multispectral (same as Landsat TM bands 1 - 4)

1. Band 1: 0.45-0.52 µm (Blue)2. Band 2: 0.52-0.60 µm (Green)3. Band 3: 0.63-0.69 µm (Red)4. Band 4: 0.76-0.90 µm (Near IR)

Launched: September 24, 1999

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October 19, 2001 DigitalGlobe launched the QuickBird-2 satellite

Spatial Resolutions:

Panchromatic data: 0.6-meterMultispectral Data: 2.5-meter

1. Blue: 0.45 - 0.52 mm2. Green: 0.52 - 0.60 mm3. Red: 0.63 - 0.69 mm4. Near-IR: 0.76 – 0.89 mm

September 3, 2003 QuickBird Satellite Panchromatic Images (0.6-m Spatial Resolution)

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QuickBird satellite image of the Jamaica Bay acquired on September 10, 2003. This is a true color display.

WorldView I, launched September 2007, collects 0.5-meter resolution imagery with an average revisit time of 1.7 days.

WorldView II, is anticipated to launch in late 2008, pending finalization of customer contracts. . 0.5-meter panchromatic resolution and 1.8-meter multispectral resolution, an average revisit time of 1 day.

DigitalGlobe WorldView I First Images (Houston)

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WorldView I, launched September 2007, collects 0.5-meter resolution imagery with an average revisit time of 1.7 days.

WorldView II, is anticipated to launch in late 2008, pending finalization of customer contracts. . 0.5-meter panchromatic resolution and 1.8-meter multispectral resolution, an average revisit time of 1 day.

DigitalGlobe WorldView I First Images (Yokohama)

GeoEye-1, a Google sponsored satellite, was successfully launched September 6, 2008. October 13, 2008, GeoEye released its first image.

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GeoEye Satellite Image taken at 11:19AM shows Washington D.C.'s National Mall and the U.S. Capitol on Jan. 20, 2009 during the Presidential inauguration.

GeoEye's next satellite, GeoEye-2, is in a phased development process for an advanced, third-generation satellite capable of discerning objects on the Earth’s surface as small as 0.25-meter (9.75 inch) in size.

The company expects to contract with a satellite builder in 2008and launch the satellite approximately three years after work begins under that contract.

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Spectral Response Curve

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Spectral Resolution

• Number of spectral bands (red, green, blue, NIR, Mid-IR, thermal, etc.)

• Width of each band• Certain spectral bands (or combinations) are good for

identifying specific ground features

• Panchromatic – 1 band (B&W)• Color – 3 bands (RGB)• Multispectral – 4+ bands (e.g. RGBNIR)• Hyperspectral – hundreds of bands

Band 1: 0.45-0.52µm (blue).Provide increased penetration of water bodies, as well as supporting analysis of land use, soil, and vegetation characteristics.

Band 2: 0.52-0.60µm (green). This band spans the region between the blue and red chlorophyll absorption bands and therefore corresponds to the green reflectance of healthy vegetation.

Band 3: 0.63-0.69µm (red).This is the red chlorophyll absorption band of healthy green vegetation and represents one of the most important bands for vegetation discrimination.

Spectral Cover ofLandsat Sensors

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• Band 4: 0.76-0.90µm (reflective infrared). This band is responsive to the amount of vegetation biomass present in the scene. It is useful for crop identification and emphasizes soil-crop and land-water contrasts.

• Band 5: 1.55-1.75µm (mid-infrared)This band is sensitive to the amount of moisture in plants and therefore useful in crop draught and in plant vigor studies.

• Band 6: 10.4-12.5µm (thermal infrared) This band measures the amount of infrared radiant flux emitted from surface.

• Band 7: 2.08-2.35µm (mid-infrared) This is an important band for the discrimination of geologic rock formation. It is effective in identifying zones of hydrothermal alteration in rocks.

Spectral Cover ofLandsat Sensors

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Comparison of Landsat Sensors

Thematic Mapper (TM) Landsat 4 and 5

Enhanced Thematic Mapper Plus (ETM+)

Landsat 7

Multispectral Scanner (MSS)

Landsat 1-5 Spectral Resolution (µm)

1. 0.45-0.52 (B) 2. 0.52-0.60 (G) 3. 0.63-0.69 (R) 4. 0.76-0.90 (NIR) 5. 1.55-1.75 (MIR) 6. 2.08-2.35 (MIR) 7. 10.4-12.5 (TIR)

1. 0.45-0.52 2. 0.53-0.61 3. 0.63-0.69 4. 0.78-0.90 5. 1.55-1.75 6. 2.09-2.35 7. 10.4-12.5 8. 0.52-0.90 (Pan)

0.5-0.6 (green) 0.6-0.7 (red) 0.7-0.8 (NIR) 0.8-1.1 (NIR)

Spatial Resolution (meter)

30 x 30 120 x 120 (TIR)

15 x 15 (Pan) 30 x 30 60 x 60 (TIR)

79 x 79

Temporal Resolution (revisit in days)

16 16 18 (Landsat 1,2,3)

Spatial coverage (km)

185 x 185 183 x 170 185 x 185

Altitude (km) 705 705 915 (Landsat 1,2,3)

Landsat-7 ETM+ Data of Providence

Landsat-7 ETM+ Data (30 m), Bands 4, 3, 2 in RGB

Landsat-7 Panchromatic Data (15 m) Landsat-7 ETM+ Data (30 m), Bands 3, 2, 1 in RGB

Landsat-7 ETM+ Data (30 m), Bands 4, 5, 3 in RGB

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Comparison of Enhanced Spatial Resolution QuickBird Multispectral Image and True Color Orthophoto

QuickBird-2 SatelliteSpatial Resolutions: 0.61 meter panchromatic; 2.5 meters multispectral

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TERRA (EOS AM) - Launched December 18, 1999

The following instruments fly on TERRA:

ASTER: Advanced Spaceborne Thermal Emission and Reflection Radiometer (15m - 3 bands in VNIR;30m - 6 bands in SWIR; 90m - 5 bands in TIR)

MODIS: Moderate Resolution Spectroradiometer (0.4 - 14.4 µm)(250m - 2 bands, 500m - 5 bands, 1000m - 29 bands)

CERES: Clouds and the Earth's Radiant Energy SystemMISR: Multi-angle Imaging SpectroradiometerMOPITT: Measurements of Pollution in

the Troposphere.

EO-1: successfully launched on November 21, 2000

ALI - Advanced Land Imager consists of a 15° Wide Field Telescope (WFT) and partially populated focal plane occupying 1/5th of the field-of-view, giving a ground swath width of 37 km.

Hyperion – Hyper-spectral sensorsa grating imaging spectrometer having a 30 meter ground sample distance over a 7.5 kilometer swath and providing 10nm (sampling interval) contiguous bands of the solar reflected spectrum from 400-2500nm.

LEISA/LAC - Linear Etalon Imaging Spectrometer Array Atmospheric Corrector (LAC) an imaging spectrometer covering the spectral range from 900 to 1600 nm which is well suited to monitor the atmospheric water absorption lines for correction of atmospheric effects in multispectral imagers such as ETM+ on Landsat. A comparison with Landsat 7 is included.

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Hyperspectral data Such as Hyperion sensor on board the EO-1 Satellite and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

Spectral profile in a single pixel location from 0.4 to 2.5 µm at 10 nm interval for a continuous coverage

over 220 bands

EO-1 launched November 21, 2000

AVIRIS

Different surface types such as water, bare ground or vegetationreflects radiation differently in various channels. The radiation reflected as a function of the wavelength is called the spectralsignature of the surface

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Concept of Hyperspectaral Remote Sensing






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Temporal ConsiderationsTime of Image Acquisition

• Seasonal differences• Phenological differences• Relationship to field sampling• Landscape dynamics• Land use and land cover changes• …

Mt.Kilimanjaro

(5,895m)

Mt. Meru(4,566m)

Forest Cover 1987

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Mt. Meru(4,566m)

Mt.Kilimanjaro

(5,895m)

Forest Cover 2000

Landsat June 21, 2000Pre-fire Sanford fire siteCentral Utah

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Landsat June 14, 2003Post-fireSanford fire siteCentral Utah

19881973

Mount St. Helens in southwestern Washington(before and after the volcanic eruption in 1980)

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Radiometric ResolutionEvery time an image is acquired by a sensor, its sensitivity to the magnitude of the electromagnetic energy determines the radiometric resolution.

The finer the radiometric resolution of a sensor, the more sensitive it is to detecting small differences in reflected or emitted energy.

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Imagery data are represented by positive digital numbers which vary from 0 to a selected power of 2. This range corresponds to the number of bits used for coding numbers in binary format. Each bit records an exponent of power 2.

The maximum number of brightness levels available depends on the number of bits used in representing the energy recorded. Thus, if a sensor used 8 bits to record the data, there would be28=256 digital values available, ranging from 0 to 255.

Maximum Values

20481024512256128643216842

Number of bits1110987654321

8 bits 11 bits

Data volume will increase as the radiometric resolution increases?

Mt. Kilimanjaro

(5,895 m)

Tanzania/Kenya

Coastal Zone

Geographic Information

for Sustainable Development

(GISD)

Shuttle Radar Topography Mission (SRTM), February 11-22, 2000, obtained the high-resolution

digital topographic database of the Earth

Digital Elevation Model (DEM) in GIS

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Ngorongoro Crater

Lake Eyasi

SeaWiFS Level-3 Standard Mapped Image October 1997

Credit line for all images: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE

SeaWiFS Level-3 Standard Mapped Image October 2001

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Examples of SeaWiFSImages

• Multispectral• Multitemporal• Multisensor• Multiresolution

Remote Sensing Data

Spatial, Temporal, and Spectral Resolutions

introduction of satellite remote sensing

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