Abstract:
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.
What is remote sensing?
Remote Sensing: remote sensing is science of acquiring, processing, and interpreting images
and related data that are obtained from ground-based, air-or space-borne instruments
that record the interaction between matter (target) and electromagnetic radiation.
Remote Sensing: using electromagnetic spectrum to image the land, ocean,
and atmosphere.
In this class, we will mostly focus on the principles and techniques
for data collection and the interaction of electromagnetic energy with the Earth's
surface some application examples also you will get familiar with ENVI, an image
processing software.
Why is remote sensing important?
Remote sensing makes it possible to collect data on dangerous or inaccessible
areas.
Remote sensing provides real time updates, and does not require active
human assistance (i.e. you can collect data at any time, at any frequency, as
long as the equipment allows it)
Remote sensing can detect things that are not normally present in
the visible spectrum - for example, temperature, or by detecting landforms underneath
the surface of the ground or ocean.
Remote sensing can scan large areas of land by satellite - much more
quickly than a ground survey ever could.
Components
Energy Source or Illumination (A) - The first requirement for remote
sensing is to have an energy source which illuminates or provides electromagnetic
energy to the target of interest.
Radiation and the Atmosphere (B)– as the energy travels from its source
to the Target, it will come in contact with and interact with the atmosphere it
passes through. This interaction may take place a second time as the energy travels
from the target to the sensor.
Interaction with the Target (C)- once the energy makes its way to the
target through the atmosphere, it interacts with the target depending on the properties
of both the target and the radiation.
Recording of Energy by the Sensor (D) - after the energy has been
scattered by, or Emitted from the target, we require a sensor (remote - not in contact
with the target) to collect and record the electromagnetic radiation.
Advantages
A) Provides data of large areas
b) Provides data of very remote and inaccessible regions
c) Able to obtain imagery of any area over a continuous period of time
through which the any anthropogenic or natural changes in the landscape can be analyzed
d) Relatively inexpensive when compared to employing a team of surveyors
e) Easy and rapid collection of data
f) Rapid production of maps for interpretation.
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