17-05-2013, 04:14 PM
Remote sensing applications: An overview
[attachment=54095]
ABSTRACT
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.
INTRODUCTION
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.
Microwave remote sensing
Microwave remote sensing is highly useful, as it provides
observation of the earth’s surface, regardless of day/night
and the atmospheric conditions. The microwaves are the
electromagnetic waves with frequencies between 109 and
1012 Hz. Radar is an active microwave remote sensing
system. The system illuminates the terrain with electromagnetic
energy, detects the scattered energy returning
from the terrain (called radar return) and then records it
as an image. Intensity of radar return, for both aircraft
and satellite-based systems, depends upon radar system
properties and terrain properties. The radar equation expresses
the fundamental relationship between the radar
parameters, the target characteristics and the received
signal.
Analysis techniques
The output of a remote sensing system is usually an image
representing the scene being observed. Many further
steps of digital image processing and modelling are required
in order to extract useful information from the image.
Suitable techniques are adopted for a given theme,
depending on the requirements of the specific problem.
Since remote sensing may not provide all the information
needed for a full-fledged assessment, many other spatial
attributes from various sources are needed to be integrated
with remote sensing data. This integration of spatial
data and their combined analysis is performed through a set
of computer software/hardware, known as Geographical
Information System (GIS).
Geographical information system
Geographical Information System (GIS) is a computerassisted
system for capture, storage, retrieval, analysis
and display of spatial data and non-spatial attribute data.
Analysis models comprise simple user defined views to
complex stochastic models. Some of these are reclassifications,
aggregation, overlays, suitability analysis, network
and route analysis, optimization, allocation/siting, etc.
The data can be derived from alternative sources such as
survey data, geographical/topographical/aerial maps or
archived data. Data can be in the form of locational data
(such as latitudes/longitudes) or tabular (attribute) data.
Applications of GIS range from simple database query
systems to complex analysis and decision support systems.
Areas of applications range from natural resources
management to crime control and near real time application
like flood warning. GIS techniques are playing an increasing
role in facilitating integration of multi-layer
spatial information with statistical attribute data to arrive
at alternate developmental scenarios17.
Evolution of Indian earth observation systems
The choice of sensor parameters is one of the most critical
concerns for both users of the data and designers of
the sensors. The observational requirements in terms of
spatial and temporal resolution are different for different
applications as time and spatial scales vary significantly
with regard to land, ocean and atmospheric phenomenon.
In order to meet the observational requirements pertaining
to assessment of natural resources, a series of Earth
Observation (EO) systems have been launched in both
polar and geosynchronous orbits. Detailed specifications
of all the sensors and satellites are given in Table 1. Joseph18
has reviewed different types of sensors, along with
their principles of operation and various tradeoffs. Kasturirangan19
has discussed the technological issues associated
with the designing of optical remote sensing
sensors. Navalgund4 has given an overview of Indian EO
system from the perspective of observational requirements
and evolution of present and future sensor systems.
A brief summary of evolution of different IRS sensors is
as follows.
Applications
Starting from the coconut root wilt disease detection using
colour infrared imageries in 1970, Indian remote sensing
applications have matured to the present status of operational
use in resource management. It is difficult to discuss
all these useful applications within the limitation of
a single article. We have tried to group the applications
into different categories. Scope of remote sensing data
under each category and details of a few national level
applications has been discussed. Future trends in each
application area are indicated.
Disaster monitoring and mitigation
The country is vulnerable to several types of disasters
causing widescale human and financial losses, every year.
Hence disaster mitigation has been one of the prime concerns
of remote sensing applications of the country. A
Disaster Management Support Programme (DMSP) has
been initiated with the setting up of a Decision Support
Centre (DSC) at NRSA43 in 2003. IRS series of satellites
and available microwave data from the international satellite
missions as well as aerial photography/Airborne
Laser Terrain Mapper (ALTM)/Airborne SAR (ASAR)
provide necessary data.
Village resource centre
To address the changing and critical needs of the rural
community, a unique experiment of setting up Village
Resource Centres (VRCs) in partnership with the reputed
NGOs and others has been initiated recently. Capabilities
in satellite communication and satellite-based earth observation
are aptly integrated to disseminate a variety of
services emanating from the space systems and other IT
tools. VRCs are envisaged as the single window delivery
mechanism for a variety of space-enabled services and
deliverables such as telemedicine; tele-education; information
on natural resources for planning and development
at local level; interactive advisories on agriculture, fisheries,
and land and water resources management; livestock
management; interactive vocational training towards skill
improvement, alternate livelihood; e-governance services;
weather information, etc. More than 170 VRCs have been
setup with active NGOs and many more are in the offing
in the coming years.
Future perspectives
Integrating EO products and services with multi-institutional
framework and people’s participation in decisionmaking
process relevant to society stand as the principle
for future direction of EO application programme. This
would turn the direction of working from being a ‘data
provider’ to ‘service provider’ by giving end-to-end solutions.
As part of this, food security, water security, environmental
monitoring and infrastructure development are
going to be the mainstay of applications with a focus on
rural development. On the other hand, the ecosystem responses
and disaster monitoring and mitigation, and climate
change studies would also stand as important
activities as they would ultimately impact the overall development.
[attachment=54095]
ABSTRACT
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.
INTRODUCTION
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.
Microwave remote sensing
Microwave remote sensing is highly useful, as it provides
observation of the earth’s surface, regardless of day/night
and the atmospheric conditions. The microwaves are the
electromagnetic waves with frequencies between 109 and
1012 Hz. Radar is an active microwave remote sensing
system. The system illuminates the terrain with electromagnetic
energy, detects the scattered energy returning
from the terrain (called radar return) and then records it
as an image. Intensity of radar return, for both aircraft
and satellite-based systems, depends upon radar system
properties and terrain properties. The radar equation expresses
the fundamental relationship between the radar
parameters, the target characteristics and the received
signal.
Analysis techniques
The output of a remote sensing system is usually an image
representing the scene being observed. Many further
steps of digital image processing and modelling are required
in order to extract useful information from the image.
Suitable techniques are adopted for a given theme,
depending on the requirements of the specific problem.
Since remote sensing may not provide all the information
needed for a full-fledged assessment, many other spatial
attributes from various sources are needed to be integrated
with remote sensing data. This integration of spatial
data and their combined analysis is performed through a set
of computer software/hardware, known as Geographical
Information System (GIS).
Geographical information system
Geographical Information System (GIS) is a computerassisted
system for capture, storage, retrieval, analysis
and display of spatial data and non-spatial attribute data.
Analysis models comprise simple user defined views to
complex stochastic models. Some of these are reclassifications,
aggregation, overlays, suitability analysis, network
and route analysis, optimization, allocation/siting, etc.
The data can be derived from alternative sources such as
survey data, geographical/topographical/aerial maps or
archived data. Data can be in the form of locational data
(such as latitudes/longitudes) or tabular (attribute) data.
Applications of GIS range from simple database query
systems to complex analysis and decision support systems.
Areas of applications range from natural resources
management to crime control and near real time application
like flood warning. GIS techniques are playing an increasing
role in facilitating integration of multi-layer
spatial information with statistical attribute data to arrive
at alternate developmental scenarios17.
Evolution of Indian earth observation systems
The choice of sensor parameters is one of the most critical
concerns for both users of the data and designers of
the sensors. The observational requirements in terms of
spatial and temporal resolution are different for different
applications as time and spatial scales vary significantly
with regard to land, ocean and atmospheric phenomenon.
In order to meet the observational requirements pertaining
to assessment of natural resources, a series of Earth
Observation (EO) systems have been launched in both
polar and geosynchronous orbits. Detailed specifications
of all the sensors and satellites are given in Table 1. Joseph18
has reviewed different types of sensors, along with
their principles of operation and various tradeoffs. Kasturirangan19
has discussed the technological issues associated
with the designing of optical remote sensing
sensors. Navalgund4 has given an overview of Indian EO
system from the perspective of observational requirements
and evolution of present and future sensor systems.
A brief summary of evolution of different IRS sensors is
as follows.
Applications
Starting from the coconut root wilt disease detection using
colour infrared imageries in 1970, Indian remote sensing
applications have matured to the present status of operational
use in resource management. It is difficult to discuss
all these useful applications within the limitation of
a single article. We have tried to group the applications
into different categories. Scope of remote sensing data
under each category and details of a few national level
applications has been discussed. Future trends in each
application area are indicated.
Disaster monitoring and mitigation
The country is vulnerable to several types of disasters
causing widescale human and financial losses, every year.
Hence disaster mitigation has been one of the prime concerns
of remote sensing applications of the country. A
Disaster Management Support Programme (DMSP) has
been initiated with the setting up of a Decision Support
Centre (DSC) at NRSA43 in 2003. IRS series of satellites
and available microwave data from the international satellite
missions as well as aerial photography/Airborne
Laser Terrain Mapper (ALTM)/Airborne SAR (ASAR)
provide necessary data.
Village resource centre
To address the changing and critical needs of the rural
community, a unique experiment of setting up Village
Resource Centres (VRCs) in partnership with the reputed
NGOs and others has been initiated recently. Capabilities
in satellite communication and satellite-based earth observation
are aptly integrated to disseminate a variety of
services emanating from the space systems and other IT
tools. VRCs are envisaged as the single window delivery
mechanism for a variety of space-enabled services and
deliverables such as telemedicine; tele-education; information
on natural resources for planning and development
at local level; interactive advisories on agriculture, fisheries,
and land and water resources management; livestock
management; interactive vocational training towards skill
improvement, alternate livelihood; e-governance services;
weather information, etc. More than 170 VRCs have been
setup with active NGOs and many more are in the offing
in the coming years.
Future perspectives
Integrating EO products and services with multi-institutional
framework and people’s participation in decisionmaking
process relevant to society stand as the principle
for future direction of EO application programme. This
would turn the direction of working from being a ‘data
provider’ to ‘service provider’ by giving end-to-end solutions.
As part of this, food security, water security, environmental
monitoring and infrastructure development are
going to be the mainstay of applications with a focus on
rural development. On the other hand, the ecosystem responses
and disaster monitoring and mitigation, and climate
change studies would also stand as important
activities as they would ultimately impact the overall development.