Short note: Remote sensing process, applications

Remote sensing process

Remote sensing is the collection of information about the Earth's surface without touching it. The process has these stages:

 Sun --> Atmosphere --> Target --> Atmosphere --> Sensor
 (A)       (B)          (C)          (B)          (D)
                                                   |
        Ground station <-- transmission <----------+
              |
        Processing & analysis --> Application

1. Energy source (A): the sun (passive) or the sensor (active) provides electromagnetic energy.
2. Radiation and atmosphere (B): energy travels to the target and back, and is partly absorbed and scattered by the atmosphere.
3. Interaction with the target (C): the surface reflects, absorbs or emits energy according to its spectral signature (e.g. vegetation, water, soil).
4. Recording by the sensor (D): satellite or aircraft sensors record the energy as images.
5. Transmission and reception: the data are sent to a ground station.
6. Processing and interpretation: corrections, enhancement and classification; visual or digital interpretation.
7. Application: the information is used in maps, reports and decisions.

Applications in civil engineering

• Land use and land cover mapping; urban growth monitoring.
• Route and site selection for roads, canals, dams, bridges and pipelines.
• Water resources, flood mapping, catchment and watershed studies.
• Geological and landslide hazard mapping, soil mapping.
• Disaster assessment after earthquakes and floods.
• DEM and contour generation; environmental impact studies.