Remote Sensing (RS) refers to the science of identification of earth surface features and estimation of their geo-biophysical properties using electromagnetic radiation as a medium of interaction. Spectral, spatial, temporal and polarization signatures are major characteristics of the sensor/target, which facilitate target discrimination. Earth surface data as seen by the sensors in different wavelengths (reflected, scattered and/or emitted) is radiometrically and geometrically corrected before extraction of spectral information. RS data, with its ability for a synoptic view, repetitive coverage with calibrated sensors to detect changes, observations at different resolutions, provides a better alternative for natural resources management as compared to traditional methods. Indian Earth Observation (EO) programme has been applications- driven and national development has been its prime
motivation. From Bhaskara to Cartosat, India’s EO capability has increased manifold. Improvements are not only in spatial, spectral, temporal and radiometric resolutions, but also in their coverage and value-added products. Some of the major operational application themes, in which India has extensively used remote sensing data are agriculture, forestry,
water resources, land use, urban sprawl, geology, environment, coastal zone, marine resources, snow and glacier, disaster monitoring and mitigation, infrastructure development, etc. The paper reviews RS techniques and applications carried out using both optical and microwave sensors. It also analyses the gap areas and discusses the future perspectives.
Keywords: Applications, image analysis, remote sensing,
signature, microwave, sustainable development.
HUMANKIND, in pursuit of its needs, has put natural resources
of the earth to a severe strain. The rate of degradation
and depletion of resources has accelerated tremendously
in view of the ever-increasing demographic pressure. Deforestation,
desertification, soil erosion and salinization
have degraded the environment, threatening the food security
and economic development of many countries. Although
India is endowed with rich natural resources and
considered as one of the important biodiversity pools for
genetic, economic and ecological prudence, it suffers
from a variety of problems, ranging from demographic
pressure to accelerated land degradation.
Agricultural food grain production, which stands at
around 210 million tonnes today needs to be increased to
325 m tonnes in the next decade or so to meet the needs
of increasing population. Improving productivity in the
rain-fed agricultural areas is one of the major concerns.
Inappropriate cropping systems, reduction in crop diversity,
inadequate post-harvest infrastructure are other major
areas of concern. Area under closed forest category is
presently half of what it was about fifty years ago. Added
to this, the increasing requirements of timber, estimated at
68,857 m tonnes in 1980, would rise to 181,270 m tonnes
by 2025, is yet another area of concern. Surface water resources
support wide ranging natural and man-made biological
systems and hence, play a key role in better
management of natural resources. However, the per capita
availability of fresh water in the country has decreased
from a healthy 5177 m3 in 1951 to 1869 m3 in 2001, which
might further decrease to 1341 m3 in 2025. Increasing
population and industrialization along the coastal areas are
adding pressure on coastal wetlands, seagrass area, and
coral reefs at an alarming rate. Global warming is showing
its impact, with the glaciers in the Indian Himalayas
showing an alarming retreat. India, owing to its geographical
location with coast on either side of its boundary,
complex mountainous terrain, bioclimate, vegetation
type and geological features, is vulnerable to several
natural disasters. About 40 m ha of land mass is prone to
floods; 5700 km out of 7500 km of coastline is prone to
cyclones; 54% of land mass is vulnerable to earthquakes
and 68% of the total geographical area is drought-prone.
Fifty-five per cent of Indian forests are prone to fires.
Considering India’s resource richness and the mounting
problems, the country needs a sustainable resources development
plan. Towards this, mapping and monitoring of
existing natural resources and forecasting the future scenarios
are highly important. Remote Sensing (RS) plays a
significant role in providing geo-information in a spatial
format and also in determining, enhancing and monitoring
the overall capacity of the earth. Satellite observations of
land, oceans, atmosphere, and specifically, during natural
and human-induced hazards have become crucial for protecting
the global environment, reducing disaster losses,
and achieving sustainable development. Remote sensing
using space-borne sensors is a tool, par excellence, for obtaining
repetitive (with a range from minutes to days) and
synoptic (with global coverage) observations. These data
could be used for a number of applications

Download full report
http://ias.accurrsci/dec252007/1747.pdf