Remote Sensing
Remote sensing is the art and
science of recording, measuring, and analyzing information about a phenomenon
from a distance. Humans with the aid of their eyes, noses, and ears are
constantly seeing, smelling, and hearing things from a distance as they move
through an environment. Thus, humans are naturally designed to be remote
sensors. In order to study large areas of the Earth’s surface geographers use
devices known as remote sensors. These sensors are mounted on platforms such as
helicopters, planes, and satellites that make it possible for the sensors to
observe the Earth from above.
Two types of sensors exist, namely passive and active.
A passive sensor system needs an external energy source. In most cases this source is the sun. These sensors generally detect reflected and emit energy wave lengths from a phenomenon.
An active sensor system provides its own energy source. As
an example, a radar sensor sends out sound waves and records the reflection
waves coming back from the surface. Passive systems are much more common than
active systems. Substance
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