Scientists predict that the use of scanning sensors will increase in the future because they produce more objective results which are easily interpreted. Extracting data from a photograph is tedious and subject to interpretation. Often the results vary with the skills of the interpreter. In contrast, data from scanning sensors can be stored and recalled for comparison. This data from scanning sensors is stored by number with each number representing the intensity of radiation emitted or reflected from the sensed object.
Sensors can be either active or passive.
Regardless of whether active or passive, most sensors produce a photographic image. Infrared color film, which depicts vegetation in various shades of red, is commonly used because it indicates subtle differences in vegetation. Information from scanning sensors on satellites is particularly useful for monitoring change in environments such as coastal wetlands, wildlife habitats, or crop production areas. Researchers can, for example, map irrigated acreage quickly and accurately through remote sensing techniques. They can easiIy distinguish irrigated fields from non-irrigated and fallow fields by analyzing data generated from scanning sensors mounted on satellites.