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Questions and Answers
What does spatial resolution in remote sensing refer to?
What does spatial resolution in remote sensing refer to?
- The edge length of a pixel in the image, representing the actual ground area. (correct)
- The time interval between two identical flights over the same area.
- The number of digital levels a sensor uses to express brightness variability.
- The number of spectral bands in the data.
A satellite in a geostationary orbit has a revisit time of approximately 100 minutes.
A satellite in a geostationary orbit has a revisit time of approximately 100 minutes.
False (B)
What is the primary difference between a whisk broom and a push broom line scanner?
What is the primary difference between a whisk broom and a push broom line scanner?
scanning method
A sensor with a high ________ resolution is more sensitive to detecting small differences in reflected energy.
A sensor with a high ________ resolution is more sensitive to detecting small differences in reflected energy.
Match the following resolutions with their definitions:
Match the following resolutions with their definitions:
Which of the following is considered a low spatial resolution?
Which of the following is considered a low spatial resolution?
Hyperspectral imagery involves capturing data in fewer than three spectral bands.
Hyperspectral imagery involves capturing data in fewer than three spectral bands.
What are the two remote sensing platforms?
What are the two remote sensing platforms?
________ satellites orbit at an altitude of approximately 36,000 km from the equator.
________ satellites orbit at an altitude of approximately 36,000 km from the equator.
Which satellite program includes Sentinel-2, known for land monitoring and climate change applications?
Which satellite program includes Sentinel-2, known for land monitoring and climate change applications?
The temporal resolution of METEOSAT is approximately 16 days.
The temporal resolution of METEOSAT is approximately 16 days.
Name three instruments aboard Sentinel-3.
Name three instruments aboard Sentinel-3.
The Landsat program captures multispectral data, including bands in the visible spectrum and ________.
The Landsat program captures multispectral data, including bands in the visible spectrum and ________.
If a remote sensing system captures data in only one spectral band, it is referred to as:
If a remote sensing system captures data in only one spectral band, it is referred to as:
Assuming consistent cloud cover of 60%, the revisit time of a satellite such as Sentinel-2 is the sole determinant of how often usable imagery can be gathered for a particular location.
Assuming consistent cloud cover of 60%, the revisit time of a satellite such as Sentinel-2 is the sole determinant of how often usable imagery can be gathered for a particular location.
Which resolution type describes the level of detail within an image based on the area represented by each pixel?
Which resolution type describes the level of detail within an image based on the area represented by each pixel?
A high spatial resolution image has a pixel size greater than 30 meters.
A high spatial resolution image has a pixel size greater than 30 meters.
What unit of measurement is used to describe spatial resolution?
What unit of measurement is used to describe spatial resolution?
The time interval between two identical flights over the same area is known as ______ resolution.
The time interval between two identical flights over the same area is known as ______ resolution.
Match the following spectral resolutions with their band characteristics:
Match the following spectral resolutions with their band characteristics:
Which of the following platforms is NOT typically used for remote sensing?
Which of the following platforms is NOT typically used for remote sensing?
Geostationary satellites orbit the Earth faster than the Earth's rotation.
Geostationary satellites orbit the Earth faster than the Earth's rotation.
What is the approximate altitude of a geostationary satellite above the equator in kilometers?
What is the approximate altitude of a geostationary satellite above the equator in kilometers?
________ orbits pass near the poles and are typically positioned 400-900 km from the equator.
________ orbits pass near the poles and are typically positioned 400-900 km from the equator.
Which of the following is an example of a sensor naming convention that combines both satellite and sensor name?
Which of the following is an example of a sensor naming convention that combines both satellite and sensor name?
The Sentinel-2 constellation consists of three satellites: 2A, 2B, and 2C.
The Sentinel-2 constellation consists of three satellites: 2A, 2B, and 2C.
What is the revisit time of the Sentinel-2 constellation when using both the 2A and 2B satellites?
What is the revisit time of the Sentinel-2 constellation when using both the 2A and 2B satellites?
The Sentinel-3 instrument dedicated to measuring sea and land surface temperature is called ________.
The Sentinel-3 instrument dedicated to measuring sea and land surface temperature is called ________.
If a sensor has a radiometric resolution of 12 bits, how many digital levels (grey levels) can it use to express variability of brightness?
If a sensor has a radiometric resolution of 12 bits, how many digital levels (grey levels) can it use to express variability of brightness?
Insanely Difficult: Consider two remote sensing systems: System A has a spatial resolution of 5m and a temporal resolution of 10 days, while System B has a spatial resolution of 10m and a temporal resolution of 5 days. For monitoring rapidly changing agricultural conditions (e.g., crop stress due to drought), which system would be theoretically more suitable, assuming all other factors (spectral and radiometric resolution) are equal, and why?
Insanely Difficult: Consider two remote sensing systems: System A has a spatial resolution of 5m and a temporal resolution of 10 days, while System B has a spatial resolution of 10m and a temporal resolution of 5 days. For monitoring rapidly changing agricultural conditions (e.g., crop stress due to drought), which system would be theoretically more suitable, assuming all other factors (spectral and radiometric resolution) are equal, and why?
Flashcards
Spatial Resolution
Spatial Resolution
The area on the ground represented by a single pixel in an image, measured in meters.
Spectral Resolution
Spectral Resolution
The number and width of spectral bands a sensor uses.
Radiometric Resolution
Radiometric Resolution
The sensitivity of a sensor to detect differences a reflected energy.
Temporal Resolution
Temporal Resolution
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Remote Sensing Platforms
Remote Sensing Platforms
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Geostationary Orbit
Geostationary Orbit
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Polar Orbit
Polar Orbit
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Remote Sensors
Remote Sensors
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Panchromatic Sensor
Panchromatic Sensor
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Multispectral Sensor
Multispectral Sensor
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Hyperspectral Sensor
Hyperspectral Sensor
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Landsat
Landsat
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Copernicus Program
Copernicus Program
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Sentinel-2
Sentinel-2
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Sentinel-3
Sentinel-3
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Spatial Resolution Definition
Spatial Resolution Definition
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Low Spatial Resolution
Low Spatial Resolution
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Medium Spatial Resolution
Medium Spatial Resolution
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High Spatial Resolution
High Spatial Resolution
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Spectral Resolution Definition
Spectral Resolution Definition
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Panchromatic
Panchromatic
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Radiometric Resolution Definition
Radiometric Resolution Definition
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Radiometric Resolution Units
Radiometric Resolution Units
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Temporal Resolution Definition
Temporal Resolution Definition
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Landsat Temporal Resolution
Landsat Temporal Resolution
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METEOSAT Temporal Resolution
METEOSAT Temporal Resolution
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Remote Sensing Platforms Examples
Remote Sensing Platforms Examples
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Geostationary Orbit Characteristics
Geostationary Orbit Characteristics
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Polar Orbit Characteristics
Polar Orbit Characteristics
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Sensor Naming Conventions
Sensor Naming Conventions
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Study Notes
Four Resolutions
- Spatial resolution determines the level of detail and area covered in an image
- Spectral resolution signifies the colours or bands captured
- Radiometric resolution determines the colour depth
- Temporal resolution determines revisit frequency
Spatial Resolution
- Spatial resolution describes the ground length represented by an image pixel
- It is measured in meters
- Low spatial resolution exceeds 30m
- Medium spatial resolution ranges from 2 to 30m
- High spatial resolution is less than 2m
- Increased spatial resolution with finer grids provides more earth surface details
Spectral Resolution
- Spectral resolution signifies spectral bands in data and band width
- Panchromatic images have 1 band
- RGB images have 3 bands
- Multispectral images contain 3+ bands, such as RGB + NIR
- Hyperspectral images contain hundreds of bands
Radiometric Resolution
- Radiometric resolution signifies the number of digital levels or grey levels a sensor uses to represent brightness variability
- It is expressed in bits as binary numbers
- 8 bits has 256 values (28)
- 11 bits has 2048 values (211)
- Finer radiometric resolution improves the detection of subtle differences in reflected energy
Temporal Resolution
- Temporal resolution is the time between identical flights over the same area
- It relates to satellite remote sensing
- Landsat's temporal resolutions is 16 days
- SPOT's temporal resolutions is 26 days
- METEOSAT's temporal resolutions is 15 minutes
- MODIS temporal resolutions is 24 to 48 hours
Platforms
- Common remote sensing platforms are space-borne (e.g., satellite), air-borne (e.g., manned aircraft, UAV), and handheld (e.g., field spectrometer)
Satellite Orbits
- Sun-synchronous (near polar) satellites and Geostationary satellites are different types of satellite orbits
- Geostationary satellites have a 24-hour orbit time, matching Earth's rotation speed
- Geostationary satellites are 36000 km from the equator, and are used for meteorological and communication purposes
- Polar orbit satellites pass near the poles at a 98° inclination to the equator and 400 - 900 km altitude with a 100-minute orbit
Sensors
-Satellites may feature multiple sensors and ENVISAT used 6 sensors
- Sensor types: Cameras, line scanners, and whisk broom vs push broom scanners
- Sensors are named by satellite (e.g., IKONOS), exact sensor (e.g., MODIS on Aqua and Terra), or satellite-sensor combination (e.g., LANDSAT 7 ETM+)
Landsat
- Landsat legacy includes: Landsat 1 (1972-1978), Landsat 2 (1975-1982), Landsat 3 (1978-1983), Landsat 4 (1982-1993), Landsat 5 (1984-2013), Landsat 6 (1993), Landsat 7 (1999-), Landsat 8 (2013-), and Landsat 9 (2021-)
- Landsat 8 bands include:
- Band 1 (Coastal/Aerosol), 0.433-0.453µm wavelength, 30m resolution
- Band 2 (Visible Blue), 0.450-0.515µm wavelength, 30m resolution
- Band 3 (Visible Green), 0.525-0.600µm wavelength, 30m resolution
- Band 4 (Visible Red), 0.630-0.680µm wavelength, 30m resolution
- Band 5 (Near Infrared), 0.845-0.885µm wavelength, 30m resolution
- Band 6 (Short Wavelength Infrared), 1.56-1.66µm wavelength, 30m resolution
- Band 7 (Short Wavelength Infrared), 2.10-2.30µm wavelength, 60m resolution
- Band 8 (Panchromatic), 0.50-0.68µm wavelength, 15m resolution
- Band 9 (Cirrus), 1.36-1.39µm wavelength, 30m resolution
- Band 10 (Long Wavelength Infrared), 10.3-11.3µm wavelength, 100m resolution
- Band 11 (Long Wavelength Infrared), 11.5-12.5µm wavelength, 100m resolution
Landsat 8
- OLI Operational Land Imager generates 9 spectral bands (1-9) on Landsat-8
- OLI images can differentiate vegetation, cultural features, biomass and vigor
- TIRS Thermal Infrared Sensor has 2 thermal bands at 100m spatial resolution, measuring earth's thermal energy for tracking land and water use.
Copernicus Program - Sentinel
- Sentinel 2 monitors land and climate, possessing a 13-band multispectral instrument
-The bands in Sentinel 2 are:
- 4 bands are 10 m
- 6 bands are 20 m
- 3 bands are 60 m.
- Sentinel 2 contains a 2A and 2B satellite constellation that has a revisit time of 10 days with one satellite and 5 days with both working together
- Sentinel 3 measures sea surface topography, sea and land surface temperature, and ocean/land surface color using four instruments
- Sentinel 3 includes OLCI (Ocean and Land Colour Instrument), SLSTR (Sea and Land Surface Temperature Instrument), SRAL (SAR Radar Altimeter), and MWR (Microwave Radiometer)
- Sentinel 1 uses a RADAR mission, with C band data via 3 satellites designated 1A, 1B, and 1C
MODIS
- MODIS (Moderate Resolution Imaging Spectroradiometer) occupies Terra (1999) and Aqua (2002) satellites
- MODIS contains 36 channels with spatial resolutions of 250 m, 500 m, and 1000 m, and produces NPP and LAI products
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