IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
  
  
  
  
   
  
     
  
  
   
  
  
  
  
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Figure 1. Study area (Gulf of Mannar 
3. MATERIALS AND METHODS 
Geocoded imagery of IRS LISS-III May 1998 (Figure 2), and 
Survey of India (SOI) toposheets have been used in this study. 
Geocoded IRS1D LISS — III imagery on 1:50,000 scale were 
visually interpreted based on image characteristics, and various 
coastal geomorphic categories were identified and mapped 
along the coast of Gulf of Mannar. In the present study, an 
image interpretation key indicating tone/colour, size and pattern 
developed by Space Applications Center, Ahmedabad SAC 
1991), was mad. The basic information like transport network, 
tanks, rivers etc are transferred from SOI toposheet. After 
identification and delineation, an accuracy test was made for 
118 sample points on SOI toposheet. The study area map was 
divided into grids and intersecting points of each grid within the 
study area were taken as sample points for validation of 
classified satellite data in ground truth checking. Over the 
ground, out of the 118 sample points, 105 points were found to 
be correctly interpreted giving an accuracy of about 90 per cent. 
The georeferenced geomorphology map was digitized, edited, 
labeled and projected using ARC-INFO GIS. Finally a coastal 
geomorohology map was generated using intercept operation of 
ARC/VIEW. The area statistics of coastal geomorphology in 
the map were generated. 
392 
4. RESULT AND DISCUSSION 
4.1 Coastal Land form 
The coastal plain between Dhanuskodi and Tuticorin has 
various geomorphic units with different types of configurations 
(Figure 3). The geomorphic units, interpreted from remotely 
sensed data and checked subsequently through fieldwork, have 
been categorized into four genetic classes — marine, fluvio- 
marine, fluvial, aeolian and biogenic landforms. 
4.1.1 Marine Landforms 
In the coastal zone various marine landform features such as 
beaches, spit, beach ridges, swales and backwater zone, 
mudflat, offshore islands, coral reefs, wave cut platform, sea 
cliff, sea cave, water logged land and strand lines have been 
identified. 
Beaches are extensively developed along the entire coastline of 
Gulf of Mannar with an average width of 105.35 m. The shore 
between Tuticorin and south of Sippikulam (2.04 km?), Vaippar 
River and Gundar River (2.56 km?), Gundar River and Palar 
River, (2.64 km?), Palar River and Kottakkarai River (2.189 
km?), Kottakkarai River and Marakkayarpattanam (2.18 km?), 
southern coastal parts of the Rameswaram Island (2.91 km?) 
and the western part of the Rameswaram Island from Pamban 
to Peikkarumbu have important beach areas in Gulf of Mannar 
coast. All along the shore the beach is observed to be gently 
sloping and marked with altered crusts and troughs that are 
formed due to wave action.