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Rs fundamentals

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This document provides an overview of remote sensing including: 1. The history of remote sensing from early aerial photography to modern satellite systems. 2. The principles of electromagnetic radiation and how different sensors capture radiation in various parts of the spectrum to analyze objects. 3. The various types of remote sensing platforms, sensors, and data products including satellites, spectral resolution, spatial resolution, temporal resolution, and applications like land cover mapping.

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Outline 1. Definition 2. History of remote sensing 3. Principles of radiation 4. Radiation-target interaction 5. Spectral signatures 6. Resolution 7. Satellite orbits 8. Applications
Remote Sensing Definition Science and art of obtaining information about an object, area or phenomenon through an analysis of data acquired by a device that is not in direct contact with the area, object or phenomenon under investigation. Lillesand, Thomas M. and Ralph W. Kiefer, Remote Sensing and Image Interpretation John Wiley and Sons, Inc, 1979, p. 1 What are some common examples of remote sensors?
History of Remote Sensing 1609 - Invention of the telescope Galileo
History of Remote Sensing 1859 - First aerial photographer Gaspard Felix Tournachon, also known as Nadar 1862 - US Army balloon corp
History of Remote Sensing 1909 - Dresden International Photographic Exhibition 1903 - The Bavarian Pigeon Corps
History of Remote Sensing 1914-1918 - World War I 1908 - First photos from an airplane First flight, Wright Bros., Dec. 1903
Electromagnetic energy is emitted in waves Amount of radiation emitted from an object depends on its temperature Planck Curve Radiation
Electromagnetic Spectrum
Remote Sensing Systems Human eye Camera Radiometer Radar Sonar Laser Passive Active { {
Remote Sensing Platforms - Ground based - Aircraft - Space shuttle - Satellite
Components of a Remote Sensing System
Remote Sensing Four Fundamental Properties For Design Image depends on the wavelength response of the sensing instrument (radiometric and spectral resolution) and the emission or reflection spectra of the target (the signal). - Radiometric resolution - Spectral resolution Image depends on the size of objects (spatial resolution) that can be discerned - Spatial resolution Knowledge of the changes in the target depends on how often (temporal resolution) the target is observed - Temporal resolution
Radiation - Target Interactions Spectral response depends on target Leaves reflect green and near IR Water reflects at lower end of visible range Incide nt R a dia tio n R e fle cte d A bs o rbe d T ra ns m itte d
Radiometric Resolution Number of Shades or brightness levels at a given wavelength Smallest change in intensity level that can be detected by the sensing system
Spectral Response Differences TM Band 3 (Red) TM Band 4 (NIR)
Pixels
80 x 80 Spatial Resolution 320 x 320 40 x 40
Application of Temporal Data: Urban Sprawl Atlanta, GA 1973 1987
Example: Black and white image - Single sensing device - Intensity is sum of intensity of all visible wavelengths Can you tell the color of the platform top? How about her sash? Spectral Resolution 0.4 袖m 0.7 袖m Black & White Images Blue + Green + Red
Spectral Resolution (Cont) Example: Color image - Color images need least three sensing devices, e.g., red, green, and blue; RGB Using increased spectral resolution (three sensing wavelengths) adds information In this case by sensing RGB can combine to get full color rendition 0.4 袖m 0.7 袖m Color Images Blue Green Red
Spectral Resolution (Cont) Example - What do you believe the image would look like if you used a blue only sensitive film? - What do you believe the image would look like if you used a green only sensitive film? - What do you believe the image would look like if you used a red only sensitive film?
Spectral Resolution (Cont) Example - Blue only sensitive film - Green only sensitive film - Red only sensitive film
Spectral Resolution (Cont) Example - What do you believe the image would look like if you used near and middle infrared sensitive film?
Spectral Resolution (Cont) Example - What do you believe the image would look like if you used a thermal infrared sensitive film? Blinded in the darkness, he extended his arms, felt around for obstacles, both to avoid and to hide behind. The men wearing infrared monocular night-vision units, the lenses strapped against their eyes by means of a head harness and helmet mount, were doubtless also carrying handguns. The others had rifles fitted with advanced infrared weapon sights. Both allowed the user to see in total darkness by detecting the differentials in thermal patterns given off by animate and inanimate objects. Ludlum, Robert, 2000: The Prometheus Deception, p. 96.
Spectral Resolution (Cont) Example (Cont) - What do you believe the image would look like if you used a thermal infrared sensitive film?
Heat - Energy Transfer Example - Thermal infrared view Note warmer objects are brighter
Spectral Resolution (Cont) Example of sampling wavelengths
Data Acquisition - Satellite Orbits Satellites: Sun-synchronous (Landsat, SPOT) Geostationary (TIROS)
Satellite Orbit Determines... what part of the globe can be viewed. the size of the field of view. how often the satellite can revisit the same place. the length of time the satellite is on the sunny side of the planet.
Types of Orbits Lower Earth Orbit (LEO) - Orbit at 500 - 3,000 km above the Earth (definition varies) - Used for reconnaissance, localized weather and imaging of natural resources. - Space shuttle can launch and retrieve satellites in this orbit - Now coming into use for personal voice and data communications - Weather satellites > Polar orbit - Note, as the satellite orbits, the Earth is turning underneath. Current NOAA satellites orbit about 700 - 850 km above Earths surface > Orbital period about every 98 - 102 min Satellite Observations
Types of Orbits (Cont) Medium Earth Orbit (MEO) - Orbit at 3,000 - 30,000 km (definition varies) - Typically in polar or inclined orbit - Used for navigation, remote sensing, weather monitoring, and sometimes communications > GPS (Global Position System) satellites 24-27 GPS satellites (21+ active, 3+ spare) are in orbit at 20,000 km (about 10,600 miles) above the Earth; placed into six different orbital planes, with four satellites in each plane One pass about every 12 h Satellite Observations
Types of Orbits (Cont) Highly Elliptical Orbits (HEO) - Typically pass low (1,000 km) over the southern regions, then loop high over the northern regions - One pass every 4 to 12 h - Used in communications to provide coverage of the higher latitudes and the polar regions Satellite Observations
Types of Orbits (Cont) Geosynchronous - Orbital period of 1 day, i.e., satellite stays over the same spot on the Earth - Orbital radius is 42,164 km or 35,786 km above the Earths surface at the Equator where the Earths radius is 6.378 * 106 m - Used for many communication satellites; > Cover a country like Australia > Dont require complex tracking dishes to receive the signals; Note: satellite stay stationary relative to Earth Satellite Observations
Types of Orbits (Cont) Geosynchronous (Cont) - Weather satellites > GOES (Geosynchronous Operational Environmental Satellites) Satellite Satellite Observations
Applications of Remote Sensing Images serve as base maps Observe or measure properties or conditions of the land, oceans, and atmosphere Map spatial distribution of features Record spatial changes
Classification - Supervised Training
Maximum Likelihood
Classification
Change Detection - Flooding Landsat imagery of the 1993 Mississippi flood
Quantifying Urban Sprawl San Francisco Bay
Change Detection - Urban Sprawl
Monitoring Weather GOES-8 Water Vapor
Detecting and Monitoring Wildland Fires Arizona, June 2002 Borneo
Monitoring Sea Surface Temperature
GOES and MODIS Spatial and Temporal Resolution GOES sounder temporal resolution every hour; spatial resolution (10 km) MODIS instrument on the polar orbiting platforms - up to four passes a day, two daytime and two nighttime; spatial resolution (1 km) AQUA MODIS 24 JAN 2004 GOES LST 2 AM CST
GOES and MODIS Spectral Resolution MODIS observes 36 separate frequencies of radiation, ranging from visible to infrared. GOES detects only five frequencies. http://science.nasa.gov/headlines/y2004/09jan_sport.htm
Land Surface Temperature (LST) Comparison Dry Period June 25-July 3, 2004 July 25-August 3, 2004 Wet Period June 26-July 3, 2005 July 23-31, 2005
LST Products MODIS/Terra Land Surface Temperature/Emissivity Daily L3 Global 1 km SIN Grid (MOD11A1) Data Set Characteristics Area = ~ 1100 x 1100 km Image Dimensions = 2 (1200 x 1200 row/column) Average File Size = 24 MB Resolution = 1 kilometer (actual 0.93 km) Projection = Sinusoidal Land Surface Temperature (LST) Data Type =16-bit Unsigned Integer Emissivity Data Type = 8-bit Unsigned Integer Data Format = HDF-EOS Science Data Sets (SDS) = 12 The MODIS/Terra Land Surface Temperature/Emissivity Daily L3 Global 1km SIN Grid product, MOD11A1, is a gridded version of the level-2 daily LST product. It is generated by projecting MOD11_L2 pixels to Earth locations on a sinusoidal mapping grid.
MODIS/Terra Land Surface Temperature/ Emissivity Daily L3 Global 1 km SIN Grid SDS Units Data Type-bit Fill Value Valid Range Multiply By Scale Factor Add Additional Offset Daily daytime 1 km grid Land- Surface Temperature Kelvin 16-bit unsigned integer 0 7500- 65535 0.0200 na Daily nighttime 1 km grid Land- Surface Temperature Kelvin 16-bit unsigned integer 0 7500- 65535 0.0200
Land Cover Products MODIS/Terra Land Cover Type Yearly L3 Global 1 km SIN Grid Version VOO4 The MOD12 classification schemes are multitemporal classes describing land cover properties as observed during the year (12 months of input data). These classes are distinguished with a supervised decision tree classification method
LEGEND MOD12Q1 Land Cover Type 5 Land Cover Class Fill Value 255 Water 0 Evergreen needleleaf trees 1 Evergreen broadleaf trees 2 Deciduous needleleaf trees 3 Deciduous broadleaf trees 4 Shrub 5 Grass 6 Cereal crop 7 Broadleaf crop 8 Urban and built up 9 Snow and ice 10 Barren or sparse vegetation 11

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Rs fundamentals

  • 1. Outline 1. Definition 2. History of remote sensing 3. Principles of radiation 4. Radiation-target interaction 5. Spectral signatures 6. Resolution 7. Satellite orbits 8. Applications
  • 2. Remote Sensing Definition Science and art of obtaining information about an object, area or phenomenon through an analysis of data acquired by a device that is not in direct contact with the area, object or phenomenon under investigation. Lillesand, Thomas M. and Ralph W. Kiefer, Remote Sensing and Image Interpretation John Wiley and Sons, Inc, 1979, p. 1 What are some common examples of remote sensors?
  • 3. History of Remote Sensing 1609 - Invention of the telescope Galileo
  • 4. History of Remote Sensing 1859 - First aerial photographer Gaspard Felix Tournachon, also known as Nadar 1862 - US Army balloon corp
  • 5. History of Remote Sensing 1909 - Dresden International Photographic Exhibition 1903 - The Bavarian Pigeon Corps
  • 6. History of Remote Sensing 1914-1918 - World War I 1908 - First photos from an airplane First flight, Wright Bros., Dec. 1903
  • 7. Electromagnetic energy is emitted in waves Amount of radiation emitted from an object depends on its temperature Planck Curve Radiation
  • 9. Remote Sensing Systems Human eye Camera Radiometer Radar Sonar Laser Passive Active { {
  • 10. Remote Sensing Platforms - Ground based - Aircraft - Space shuttle - Satellite
  • 11. Components of a Remote Sensing System
  • 12. Remote Sensing Four Fundamental Properties For Design Image depends on the wavelength response of the sensing instrument (radiometric and spectral resolution) and the emission or reflection spectra of the target (the signal). - Radiometric resolution - Spectral resolution Image depends on the size of objects (spatial resolution) that can be discerned - Spatial resolution Knowledge of the changes in the target depends on how often (temporal resolution) the target is observed - Temporal resolution
  • 13. Radiation - Target Interactions Spectral response depends on target Leaves reflect green and near IR Water reflects at lower end of visible range Incide nt R a dia tio n R e fle cte d A bs o rbe d T ra ns m itte d
  • 14. Radiometric Resolution Number of Shades or brightness levels at a given wavelength Smallest change in intensity level that can be detected by the sensing system
  • 15. Spectral Response Differences TM Band 3 (Red) TM Band 4 (NIR)
  • 17. 80 x 80 Spatial Resolution 320 x 320 40 x 40
  • 18. Application of Temporal Data: Urban Sprawl Atlanta, GA 1973 1987
  • 19. Example: Black and white image - Single sensing device - Intensity is sum of intensity of all visible wavelengths Can you tell the color of the platform top? How about her sash? Spectral Resolution 0.4 袖m 0.7 袖m Black & White Images Blue + Green + Red
  • 20. Spectral Resolution (Cont) Example: Color image - Color images need least three sensing devices, e.g., red, green, and blue; RGB Using increased spectral resolution (three sensing wavelengths) adds information In this case by sensing RGB can combine to get full color rendition 0.4 袖m 0.7 袖m Color Images Blue Green Red
  • 21. Spectral Resolution (Cont) Example - What do you believe the image would look like if you used a blue only sensitive film? - What do you believe the image would look like if you used a green only sensitive film? - What do you believe the image would look like if you used a red only sensitive film?
  • 22. Spectral Resolution (Cont) Example - Blue only sensitive film - Green only sensitive film - Red only sensitive film
  • 23. Spectral Resolution (Cont) Example - What do you believe the image would look like if you used near and middle infrared sensitive film?
  • 24. Spectral Resolution (Cont) Example - What do you believe the image would look like if you used a thermal infrared sensitive film? Blinded in the darkness, he extended his arms, felt around for obstacles, both to avoid and to hide behind. The men wearing infrared monocular night-vision units, the lenses strapped against their eyes by means of a head harness and helmet mount, were doubtless also carrying handguns. The others had rifles fitted with advanced infrared weapon sights. Both allowed the user to see in total darkness by detecting the differentials in thermal patterns given off by animate and inanimate objects. Ludlum, Robert, 2000: The Prometheus Deception, p. 96.
  • 25. Spectral Resolution (Cont) Example (Cont) - What do you believe the image would look like if you used a thermal infrared sensitive film?
  • 26. Heat - Energy Transfer Example - Thermal infrared view Note warmer objects are brighter
  • 27. Spectral Resolution (Cont) Example of sampling wavelengths
  • 28. Data Acquisition - Satellite Orbits Satellites: Sun-synchronous (Landsat, SPOT) Geostationary (TIROS)
  • 29. Satellite Orbit Determines... what part of the globe can be viewed. the size of the field of view. how often the satellite can revisit the same place. the length of time the satellite is on the sunny side of the planet.
  • 30. Types of Orbits Lower Earth Orbit (LEO) - Orbit at 500 - 3,000 km above the Earth (definition varies) - Used for reconnaissance, localized weather and imaging of natural resources. - Space shuttle can launch and retrieve satellites in this orbit - Now coming into use for personal voice and data communications - Weather satellites > Polar orbit - Note, as the satellite orbits, the Earth is turning underneath. Current NOAA satellites orbit about 700 - 850 km above Earths surface > Orbital period about every 98 - 102 min Satellite Observations
  • 31. Types of Orbits (Cont) Medium Earth Orbit (MEO) - Orbit at 3,000 - 30,000 km (definition varies) - Typically in polar or inclined orbit - Used for navigation, remote sensing, weather monitoring, and sometimes communications > GPS (Global Position System) satellites 24-27 GPS satellites (21+ active, 3+ spare) are in orbit at 20,000 km (about 10,600 miles) above the Earth; placed into six different orbital planes, with four satellites in each plane One pass about every 12 h Satellite Observations
  • 32. Types of Orbits (Cont) Highly Elliptical Orbits (HEO) - Typically pass low (1,000 km) over the southern regions, then loop high over the northern regions - One pass every 4 to 12 h - Used in communications to provide coverage of the higher latitudes and the polar regions Satellite Observations
  • 33. Types of Orbits (Cont) Geosynchronous - Orbital period of 1 day, i.e., satellite stays over the same spot on the Earth - Orbital radius is 42,164 km or 35,786 km above the Earths surface at the Equator where the Earths radius is 6.378 * 106 m - Used for many communication satellites; > Cover a country like Australia > Dont require complex tracking dishes to receive the signals; Note: satellite stay stationary relative to Earth Satellite Observations
  • 34. Types of Orbits (Cont) Geosynchronous (Cont) - Weather satellites > GOES (Geosynchronous Operational Environmental Satellites) Satellite Satellite Observations
  • 35. Applications of Remote Sensing Images serve as base maps Observe or measure properties or conditions of the land, oceans, and atmosphere Map spatial distribution of features Record spatial changes
  • 39. Change Detection - Flooding Landsat imagery of the 1993 Mississippi flood
  • 41. Change Detection - Urban Sprawl
  • 43. Detecting and Monitoring Wildland Fires Arizona, June 2002 Borneo
  • 44. Monitoring Sea Surface Temperature
  • 45. GOES and MODIS Spatial and Temporal Resolution GOES sounder temporal resolution every hour; spatial resolution (10 km) MODIS instrument on the polar orbiting platforms - up to four passes a day, two daytime and two nighttime; spatial resolution (1 km) AQUA MODIS 24 JAN 2004 GOES LST 2 AM CST
  • 46. GOES and MODIS Spectral Resolution MODIS observes 36 separate frequencies of radiation, ranging from visible to infrared. GOES detects only five frequencies. http://science.nasa.gov/headlines/y2004/09jan_sport.htm
  • 47. Land Surface Temperature (LST) Comparison Dry Period June 25-July 3, 2004 July 25-August 3, 2004 Wet Period June 26-July 3, 2005 July 23-31, 2005
  • 48. LST Products MODIS/Terra Land Surface Temperature/Emissivity Daily L3 Global 1 km SIN Grid (MOD11A1) Data Set Characteristics Area = ~ 1100 x 1100 km Image Dimensions = 2 (1200 x 1200 row/column) Average File Size = 24 MB Resolution = 1 kilometer (actual 0.93 km) Projection = Sinusoidal Land Surface Temperature (LST) Data Type =16-bit Unsigned Integer Emissivity Data Type = 8-bit Unsigned Integer Data Format = HDF-EOS Science Data Sets (SDS) = 12 The MODIS/Terra Land Surface Temperature/Emissivity Daily L3 Global 1km SIN Grid product, MOD11A1, is a gridded version of the level-2 daily LST product. It is generated by projecting MOD11_L2 pixels to Earth locations on a sinusoidal mapping grid.
  • 49. MODIS/Terra Land Surface Temperature/ Emissivity Daily L3 Global 1 km SIN Grid SDS Units Data Type-bit Fill Value Valid Range Multiply By Scale Factor Add Additional Offset Daily daytime 1 km grid Land- Surface Temperature Kelvin 16-bit unsigned integer 0 7500- 65535 0.0200 na Daily nighttime 1 km grid Land- Surface Temperature Kelvin 16-bit unsigned integer 0 7500- 65535 0.0200
  • 50. Land Cover Products MODIS/Terra Land Cover Type Yearly L3 Global 1 km SIN Grid Version VOO4 The MOD12 classification schemes are multitemporal classes describing land cover properties as observed during the year (12 months of input data). These classes are distinguished with a supervised decision tree classification method
  • 51. LEGEND MOD12Q1 Land Cover Type 5 Land Cover Class Fill Value 255 Water 0 Evergreen needleleaf trees 1 Evergreen broadleaf trees 2 Deciduous needleleaf trees 3 Deciduous broadleaf trees 4 Shrub 5 Grass 6 Cereal crop 7 Broadleaf crop 8 Urban and built up 9 Snow and ice 10 Barren or sparse vegetation 11