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for identification of mineral prognostic areas. Two similar projects in Northern
and Eastern regions of India viz., Project ' Bhu Sampada' and Project 'Singhbhumi'
have also been initiated by the Geological Survey of India using LISS-I & II data.
The above studies have indicated that LISS-I data is very good for regional
geological study. The rock boundaries in most of the cases are differentiable
easily and details on structural features such as folds, faults, fractures, dykes
etc. are very clear both on LISS-I and LISS-II data. In most of the cases details
derivable regarding rock types, structures and geomorphology on LISS-I and LISS-II
data have been found comparable with those reflected in Landsat MSS and TM data
respectively. However details depicted on IRS-1A data are much clearer and sharp
(Ravindran, 1988, Bhattacharya et.al, 1988).
2.7 Ocean Resources and Coastal Studies
Ocean/coastal applications of IRS-1A data include wetland mapping, offshore sediment
dispersal, mapping mangroves, coastal zone geomorphological mapping etc. Several
studies using IRS-1A data for wetland and coastal zone mapping monitoring offshore
sediment dispersal pattern have been carried out using visual and digital analysis
techniques and results compared with those of Landsat and SPOT data products. A
coastal atlas of the country (about 6000 km of coastline) using IRS-1A LISS-II data
and Landsat TM data depicting coastal landforms, water features, suspended sediment
levels etc. is under preparation by Department of Space. The results of the above
studies indicate that details derivable on LISS-I & II data of IRS-1A are comparable
with those of Landsat MSS and TM data respectively. In many of the cases details
derivable from LISS-II data have been found better as compared with Landsat TM
mainly due to better clarity of features on IRS LISS-II data. Regarding wetland
mapping details upto level 2 and level 3 in many cases could be derived using LISS-
II imagery. In a case study better separation of mangroves from marshy and saline
from sandy areas was obtained on LISS-II data compared to Landsat TM on 1:250,000
scale. The coastal zone mapping of Bombay area reported better clarity of features
on LISS-II (1:100,000 scale) imagery than on the Landsat TM data of same scale and
upto 7 categories fo coastal zone units could be discriminated as against 9
categories from aerial photographs (Nayak, 1988) . Various digital techniques such
as linear contrast stretching, generation of FCCs, principal component analysis and
detailed spectral analysis using statistical parameters of IRS LISS-I have been
performed to identify the areas having scattered remarks of Deccan Trap basic
volcanic rocks in Lalitpur district of Uttar Pradesh (Krishnamurthy, 1990).
2.8 Drought
Applications of IRS-1A data for agricultural drought assessment and monitoring for
combating drought include generation of Normalised Difference Vegetation Index Maps
(NDVI maps) for assessment of drought affected areas, at the micro level in
conjunction with NOAA data. Towards this biweekly NDVI maps for Kharif season are
being generated. Whereas the above NDVI maps are at regional scale and provide
information at state and district level. NDVI maps generated using LISS-I data give
information on drought affected areas at sub district/ta 1uk level. Under
'Integrated Land and Water Resources Planning' project, IRS-1A data is being used to
generate basic resources information pertaining to drought affected regions. Under
this project ground water and surface water potential, geomorphology, geology and
soils, vegetation, landuse etc are integrated towards developing a scientific plan
of action for drought alleviation on short and long term basis. Under this project
initially 18 drought prone districts in the country have been taken up for the
integrated study using IRS LISS-II data.
2.9 Flood Prone Area Delineation and Flood Mapping
In India, flooding in several major rivers during monsoon season (June-Sept)every
year cause extensive damage (40 m.ha annually) . In order to have real time
information on areas affected due to floods towards taking up rehabilitation
measures, satellite data is being operationally used since 1986. All the major
floods during 1988 and 1989 were mapped exclusively using IRS data.
During the recent cyclone of May 1990 which affected the entire south east coast of
India and caused extensive damage by inundating over 18,000 sq.km area and marooning
600 villages, the IRS images provided an objective assessment of the severity of
the damage. This damage assessment using IRS LISS-I data was the only way to
quantify the crop damages due to flooding as the communication links were totally
affected.
CONCLUSION
IRS mission envisages continuity of data to users and towards this plans are afoot
to launch IRS-1B which is identical to IRS-1A during mid-1991 and the second