The Ultimate Limitation

A sensor's various resolutions are very important characteristics.
These resolution categories include:

• spatial
• spectral
• temporal
• radiometric

Spatial resolution is a measure of the smallest object that can be resolved by the sensor, or the linear dimension on the ground represented by each pixel or grid cell in the image [See Image 20].

Spectral resolution describes the specific wavelengths that the sensor can record within the electromagnetic spectrum.  For example, the “photographic infrared” band covers from about 0.7 – 1.0 micrometers.

Temporal resolution is a description of how often a sensor can obtain imagery of a particular area of interest. For example, the Landsat satellite revisits an area every 16 days as it orbits the Earth, while the SPOT satellite can image an area every 1 to 4 days.

Radiometric resolution refers to the number of possible brightness values in each band of data and is determined by the number of bits into which the recorded energy is divided. In 8-bit data, the brightness values can range from 0 to 255 for each pixel (256 total possible values). In 7-bit data, the values range from 0 to 127, or half as many possible values.