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


                                                                            Image/Diagram courtesy : Google image search engine
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