Page 7 - RemoteSnsing&GIS by PK Gogoi

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sensory organs,viz. Eyes, Nose, Ears act as a receiving these shades of colour through our acquisition process of remote sensing, data in

remote sensing mechanism. Through ages of eyes , we can able to interpret the meaning of the form of EMR (Electromagnetic Radiation)
he word Remote Sensing is a
biological evolution, animals (including the sentences. (We may apply this procedure to are acquired by sensors as reflected rays of
Tcombination of two words ‘Remote’
people)have many natural receptors to sense understand the Remote Sensing Process.). terrestrial features. On the other hand, data
meaning ‘far away’ and ‘Sensing” meaning to
different forms of energy .’Eye’ can detect henever in real world scenario, the analysis is the process in which received data
perceive or acquire.. The term "remote sensing"
visible portion of electromagnetic energy in the Wremote sensing is used as a area being analysed by users with tools and
is itself a relatively new addition to the
form of light. ‘Ears’ detect acoustic (sound) technological basis of spatial data acquisition , techniques.
technical lexicon .It was coined by Ms Evelyn
energy by acquiring vibration in the form of the reflected form of energy from objects, areas .2.The Elements of Remote Sensing
Pruitt in the mid- 1950's when she was with or phanomana being investigated are received 1
wave from an object .Similarly,’Nose’ contains
the U.S. Office of Naval Research he elements remote sensing is nothing
sensitive chemical receptors that respond to by specially designed electronic device called
ssentially , Remote sensing is Tbut the different process being
minute amounts of airborne chemicals given Sensor. The reflected waves are of different
Edefined as the science (and to some involved in data acquisition and later, data
off by the materials in our surroundings. There types viz. gravity waves, acoustic waves
extent, art) of acquiring information analysis. Theses are mentioned as under :
are studies which reveals that, animals too (sonar) and in the form of electromagnetic
about the earth's surface without . Energy Source or Illumination (A)
have equally developed remarkable use of such waves (EMR). This EMR is used for
actually being in contact with it. This is 1and Radiation principles -: In remote
organs and sometimes re modified these organs inventorying, mapping and monitoring earths
done by sensing and recording of sensing it is the primary requirement for
for their survival in nature. Dolphin, uses their resources using various kinds of sensors which
reflected or emitted energy and receiving of data as it illuminates or provides
typical sense of reflected vibration of sound are being placed at terrestrial to space borne
processing, analyzing, and applying that electromagnetic energy to the target of interest.
energy to view to move in river. platforms. For a better understanding, have a
information. Literally, remote sensing is . Radiation and the Atmosphere (B) :As
odestly saying, the functioning of look at the different platform (A spacial
the science of obtaining and interpreting 2the energy travels from its source to the
Mremote sensing can be attributed to discussion on remote sensing platform has been
information from a distance, using target or earth surface, it will come in contact
that of the reading process. Our eyes are acting referred in this book in the following chapter)
sensors placed on a areal platform that with atmospheric elements . This interaction
as sensors or receptors (organ that receives Fig: 1 Earth Topography and Remote
are not in physical contact with the may again take place for the second time as the
light) that respond to the light reflected from
object of the earth being observed. energy travels from the target to the sensor.
any kinds of object (supposing from this page
hus, the Remote Sensing is the science of (Detailed discussion is available in advance
itself). Lets consider that this page of the book
Tacquiring information about the earth learning topic in next chapter.)
has many letters forming sentences. In
using instruments which are remote to the . Interaction with the Target (C) - Once
technical scene, each letters in this page has
earth's surface, usually from aircraft or 3the energy reaches the target through the
different pattern of dark and light shades of
satellites. Instruments may use visible light, atmosphere, it interacts with the target(earth’s
colour and from this page, light is being
infrared or radar to obtain data. Remote sensing surface) depending on the properties of both the
reflected back to our eyes. Firstly, in viewing or
offers the ability to observe and collect data for target and the radiation.
reading ,there needs to be a source of light like
large areas relatively quickly, and is an
sun light or an artificial source of light. The . Recording of Energy by the Sensor (D)
important source of data for GIS. (Source:
reflected rays from the page are sensed by our Sensing 4- After the energy is scattered by, or emitted
digicam)
eyes (act as a sensor) and the received (radiated back) from the target, a sensor (placed
roadly, in remote sensing two distinctive
aturally, we are familiar with the process information from the page are finally analysed at the different platform) collects and record the
Bprocess are involved viz. I) data
Nof remotely sensed information. Our by our brain or as human computer.Thus, after electromagnetic radiation.
acquisition and II) data analysis. In data

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