The view from above

  • Created by: catehrine
  • Created on: 16-04-20 13:05

Remote sensing


  • Remote sensing relies on electromagnetic radiation
  • an e-m wave is characterised by amplitude, frequency and wavelength
  • The waves travel at the speed of light
  • amplitude affects brightness and wavelength affects temperature

Active sensors 

  • generate waves themselves
  • radar/laser

Passive sensors

  • natural light is used
  • Optical satellite imagery
  • sunrays
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Absorbtion, reflection and emission

How an object defers waves is dependent on its optical properties

Different compounds and elements present in nature reflect different parts of the e-m spectrum

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Acquiring imagery

Sensors = record the data 

Platforms = hold the sensor

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Resolution 1


  • level of spatial detail
  • Raster images
  • high resolution means there is more detail but it is in a larger file


  • precision to which a sensor can identify the wavelength of radiaiton
  • Low = only three colours
  • Lansat bands - different parts of data from the satellite 
  • multispectral = multiple bands
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Resolution 2


  • Greyscale
  • amount of energy and radiation it recieves 
  • high = distinguishes between loads of energy levels
  • 8 bit colour is the one used


  • frequency the data is colleccted at
  • revisited time
  • depends on orbital height and path
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Satellite remote sensing

Field of view

  • the angle the satellite hits the earth measured in radians

Swath width

  • the area of the earth the satellite sees with angle and height influencing it

Across track seperation

  • the overlap between satellites

False colour images

  • three bands of images

Elevation data

  • we know the speed so measure the time the wavelength comes back to work out distance
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Landsat Program


Landsat 8 in 2013

Each different sensor looks at a different landsat band

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Aerial remote sensing

Aerial photography

Flase colour images can show mining 


Airborne laser scanning

  • Mounted
  • Laser emitted out and measure the time it takes to comne back
  • Monitor vegetation
  • It can map out the trees on the ground and detect leaves on the floor showing a changing distance therefore season
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Terrestrial remote sensing

On the ground

Uses a digital camera

  • the more pixels there are the more detailed it will be

Terrestrial laser scanning

  • Map out the coastline to track the erosion of the cliffs
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Imaging the earth

To determine change

Atmospheric remote sensing

Air quality

  • track what are human emissions and what are sourced naturally


  • water depth and grain size
  • partial image velocity 
    • velocity = displacement/time between images taken
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