Page 6 - 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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