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545 Application of Remote Sensing and GIS

                              regeneration/ regrowth of forest area and tracing major changes in land
                                     Remote  sensing  data  derived  from  different  satellite  such  as
                              Landsat  MSS  data  can  provide  us  information  about  the  areal  extent,
                              conditions  and  boundary  of  coastal  wetlands.  Further,  multidated
                              satellite data can be used effectively to find out the changes in the aereal
                              extent of mangroves. Sequential nature of IRS data provide opportunity
                              to monitor changes in the landuse activities in the mangroves. IRS has
                              been  quite  extensively  used  for  Mangrove  landuse  pattern  both  the
                              visual  as  well  as  the  digital  analysis  of  IRS  data  provide  useful

                                     Data acquired by both passive and active remote sensing systems
                              can be used in the study of mangroves. The research involves two main
                              steps. In the first step, a broad classification of the general land cover,
                              including mangroves is made (Figure1). This indicates the best approach
                              to  dealing  with  the  various  types  of  imagery  in  order  to  detect  the
                              mangrove  deforestation.  The  second  step  concentrates  on  the  specific
                              problem  of  detecting  changes  in  the  mangrove  areas  (Figure2).  It
                              examines different approaches for monitoring the nature of the changes
                              in order to produce maps showing the current and former conditions in
                              an  area.  SAR  data,  which  is  independent  of  cloud,  cover and weather
                              interference  can  be  used  for  mapping  mangrove  and  estimation  of
                              mangrove biomass.
                                     One of the sub tasks of Land Ocean Interactions in the Coastal
                              Zone  (LOICZ)  of  IGBP  project  is  to  develop  a  methodology  for
                              mangrove  zonation,  succession  and  regeneration  (IGBP,  1994).  The
                              important  tasks  for  the  study  of  mangroves  are  mapping  and  change
                              detection,  identification  of  species/  plant  communities  and  biomass
                              estimation.  To  prepare  a  management  plan  for  mangroves,  a
                              comprehensive database should be available, including the information
                              on distribution and extent of mangrove areas and species composition.
                              As a first step towards this, the Space Applications Centre has carried
                              out national level wetlands mapping to prepare shoreline change maps
                              and wetland maps on 1: 250,000 scale (SAC, 1992). This work presented
                              the status of wetlands, primarily the level‐I and level‐II categories and
                              the total area of mangroves has been estimated to be about 4000 sq. km.
                                     Although  the  methodology  for  visual  interpretation  of  satellite
                              data  for  vegetation/  land  cover  classification  and  mapping  has  been
                              standardized  and  made  operational  in  India,  the  potential  of  high
                              resolution data such as IRS LISS‐II and LISS‐III for extracting vegetation‐
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