Remote Sensing: Definition and Applications

Remote Sensing: Definition and Applications

• Remote sensing is the process of acquiring information about the earth's surface using images taken from an overhead perspective.
• It uses electromagnetic radiation (EMR) reflected or emitted from the earth's surface in different regions of the electromagnetic spectrum.
• The process is often used to study environmental issues and natural resources, like:
  • Topography
  • Drainage
  • Temperature
  • Tectonic motion
  • Urban and regional planning
  • Natural resource inventories
  • Monitoring environmental issues
  • Agriculture (crop forecasting, precision farming)
  • Geology, hydrologic studies
  • Land cover
  • Benthic cover mapping
  • Soil surveys (soil moisture)
  • Military reconnaissance
  • Atmospheric applications (precipitation, clouds, concentration of gases)
  • Ocean (temperature, color)
  • Renewable energy assessment

Remote Sensing System: Considerations

• The best method for acquiring information depends on the following:
  • Does the information required change with spatial position? (point observations, interpolation needed)
  • Is the information dependent on time? (data collection at regular intervals, for change detection and mapping)
  • Does the collection of required information affect the resource being monitored, cause time delays, or create administrative or cost issues? (timeliness)
  • Can the required information be reliably extracted from image data? (EMR-material interaction, cloud cover, day or night acquisition)
  • Can the information be obtained directly from data or through its relationship with other physical characteristics of the environment?

Remote Sensing Examples:

• Puerto Galera, Philippines:
  • QuickBird image data displayed in different bands: Blue (0.45-0.52 µm), Green (0.52-0.60 µm), Red (0.63-0.69 µm), NIR (0.76-0.90 µm)
  • True color composites (R-G-B) and false color composites (NIR-R-G) are used for visual interpretation.
• Water Quality Mapping:
  • Remote sensing is used to monitor and assess water quality changes.
• Mt. Pinatubo, Philippines:
  • RADARSAT radar backscatter image (February 1998) and SPOT image (December 1991) were used to study changes in the lahar deposits caused by the eruption.
• Meteorology:
  • Typhoon tracking using satellite imagery data, like the example of Super Typhoon Rosita.
• Disaster Management:
  • Visualization of the aftermath of Typhoon Yolanda (02/23/2012 vs. 11/10/2013) highlighting the impact of the disaster and post-disaster response.
• Renewable Energy Assessment:
  • Estimated theoretical solar PV power potential (PPV) assessed using remote sensing data.
• Fishing Ground Identification:
  • Machine learning applied to Earth Observation data for identifying fishing grounds in the Philippines.
• Flood Extent Mapping:
  • Remote sensing used to map the extent of floods and understand their impact.
• Volcanic Eruptions:
  • Mapping sulfur dioxide emissions surrounding Mt. Bulusan and Mt. Mayon during eruptions, using remote sensing data.

Advantages of Remote Sensing

• Provides a permanent record of an area at a point in time.
• Data is relatively consistent spatially and temporally.
• Does not interfere with the resources being measured.
• Can provide direct information or insights using the relationship with other environmental characteristics.