5.3. Resolution of Sensors

Objectives

The objective of this learning object is to explain the different aspects of resolution in remote sensing.

“The ability of an imaging system to record fine details in a distinguishable manner” (Estes and Simonett, 1975)

Essentially, there are four different types of resolution affecting sensors. These are:

  • Spatial resolution – refers to the size of objects on the ground which can be detected
  • Spectral resolution – refers to the smallest portion of electromagnetic radiation which can be detected
  • Radiometric resolution – refers to the level of the signal
  • Temporal resolution – refers to the time interval between sensor visits to the same area

(Juggling image source: CCRS)

It is important to understand that it is not possible to increase all these resolutions at the same time: there are trade-offs which have to be made between them. To increase the amount of energy detected (higher radiometric resolution) without reducing spatial resolution, we would have to broaden the wavelength range detected for a band. This would reduce the spectral resolution. Thus the inter-relationships between the different types of resolution can be quite complex. Coarser spatial resolution would allow improved radiometric and/or spectral resolution.

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