560
26.3 Issues and Applications
It is important to prepare inventory of wetlands
and their catchments in order to conserve and
manage these unique resources. Also, it is essential to store and analyse the data. Digital maps
are very useful tools to achieve this objective.
Maps relate the feature to any given geographical
location which has a strong visual impact. Maps
are essential for monitoring and quantifying
change over time scale, and thus, they assist in
decision making. The technique used in the
preparation of map started with ground survey.
The Survey of India (SOI) topographical maps
(toposheets) are the earliest true maps of India
showing various land use/cover classes including wetlands. Recent years have seen advances
in mapping technique to prepare maps with
much more information based on remote sensing (RS) and geographical information system
(GIS) techniques.
RS is now recognised as an essential tool for
viewing, analysing, characterising and making
decisions about land, water and atmospheric
components. From a general perspective, RS is
the science of acquiring and analysing information about objects or phenomena from a distance
(Jensen 2000 ; Lillesand and Kiefer 1987 ). Today,
satellite RS could be defi ned as the use of
satellite- borne sensors to observe, measure and
record the electromagnetic radiation (EMR)
refl ected or emitted by the earth and its environment for subsequent analysis and extraction of
information. EMR sensors include visible light;
near-, mid- and far-infrared (thermal); microwave; and long-wave radio energy. The capability
of multiple sources of information is unique to
RS. Of specifi c advantage is the spectral, temporal and spatial resolution. Spectral resolution
refers to the width or range of each spectral band
being recorded. Since each target affects different wavelengths of incident energy differently,
they are absorbed, refl ected or transmitted in different proportions. At present, there are many
kinds of RS satellites for land resource that have
sensors operating in the green, red, near-infrared
and short-wave infrared regions of the electromagnetic spectrum giving a defi nite spectral signature of various targets due to difference in
radiation absorption and refl ectance of targets.
These sensors are of common use for land cover
studies, including wetlands . Since the early
1960s, several satellites with suitable sensors
have been launched into orbit to observe and
monitor the earth and its environment. Most
early satellite sensors acquired data for meteorological purposes. The advent of earth resource
satellite sensors (those with a primary objective
of mapping and monitoring land cover) had been
initiated when the fi rst Landsat satellite was
launched in July 1972. At present, more than a
dozen orbiting satellites of various types provide
data crucial to improving our knowledge of the
earth’s atmosphere, oceans, ice, snow and land.
Of particular interest to India is the indigenous
series of satellites called Indian Remote Sensing
Satellites (IRS Series). Since the launch of the
fi rst satellite IRS 1A in 1987, India has now a
number of satellites providing data in multispectral bands with different spatial resolution. IRS
P6/RESOURCESAT 1 is the current generation
satellite that provides multispectral images in
spatial resolution of 5.8 m (LISS IV), 23.5 m
(LISS III) and 56 m (AWiFS). Over the past few
decades, Indian RS data has been successfully
used in various fi elds of natural resources.
Further, development of technologies like GIS
has enhanced the use of RS data to obtain
accurate geospatial database. GIS specialises in
handling related, spatially referenced data,
combining mapped information with other data
and acts as analytical tool for research and
decision making. During the past few decades,
technological advances in the fi eld of satellite
RS sensors, computerised mapping techniques,
global positioning system (GPS) and GIS have
enhanced the ability to capture more detailed
and timely information about the natural
resources at various scales catering to the needs
of studies at the local, regional, national and
global levels.
26 Habitat Mapping of the Wetlands on GIS Platform
26.3 Issues and Applications
It is important to prepare inventory of wetlands
and their catchments in order to conserve and
manage these unique resources. Also, it is essential to store and analyse the data. Digital maps
are very useful tools to achieve this objective.
Maps relate the feature to any given geographical
location which has a strong visual impact. Maps
are essential for monitoring and quantifying
change over time scale, and thus, they assist in
decision making. The technique used in the
preparation of map started with ground survey.
The Survey of India (SOI) topographical maps
(toposheets) are the earliest true maps of India
showing various land use/cover classes including wetlands. Recent years have seen advances
in mapping technique to prepare maps with
much more information based on remote sensing (RS) and geographical information system
(GIS) techniques.
RS is now recognised as an essential tool for
viewing, analysing, characterising and making
decisions about land, water and atmospheric
components. From a general perspective, RS is
the science of acquiring and analysing information about objects or phenomena from a distance
(Jensen 2000 ; Lillesand and Kiefer 1987 ). Today,
satellite RS could be defi ned as the use of
satellite- borne sensors to observe, measure and
record the electromagnetic radiation (EMR)
refl ected or emitted by the earth and its environment for subsequent analysis and extraction of
information. EMR sensors include visible light;
near-, mid- and far-infrared (thermal); microwave; and long-wave radio energy. The capability
of multiple sources of information is unique to
RS. Of specifi c advantage is the spectral, temporal and spatial resolution. Spectral resolution
refers to the width or range of each spectral band
being recorded. Since each target affects different wavelengths of incident energy differently,
they are absorbed, refl ected or transmitted in different proportions. At present, there are many
kinds of RS satellites for land resource that have
sensors operating in the green, red, near-infrared
and short-wave infrared regions of the electromagnetic spectrum giving a defi nite spectral signature of various targets due to difference in
radiation absorption and refl ectance of targets.
These sensors are of common use for land cover
studies, including wetlands . Since the early
1960s, several satellites with suitable sensors
have been launched into orbit to observe and
monitor the earth and its environment. Most
early satellite sensors acquired data for meteorological purposes. The advent of earth resource
satellite sensors (those with a primary objective
of mapping and monitoring land cover) had been
initiated when the fi rst Landsat satellite was
launched in July 1972. At present, more than a
dozen orbiting satellites of various types provide
data crucial to improving our knowledge of the
earth’s atmosphere, oceans, ice, snow and land.
Of particular interest to India is the indigenous
series of satellites called Indian Remote Sensing
Satellites (IRS Series). Since the launch of the
fi rst satellite IRS 1A in 1987, India has now a
number of satellites providing data in multispectral bands with different spatial resolution. IRS
P6/RESOURCESAT 1 is the current generation
satellite that provides multispectral images in
spatial resolution of 5.8 m (LISS IV), 23.5 m
(LISS III) and 56 m (AWiFS). Over the past few
decades, Indian RS data has been successfully
used in various fi elds of natural resources.
Further, development of technologies like GIS
has enhanced the use of RS data to obtain
accurate geospatial database. GIS specialises in
handling related, spatially referenced data,
combining mapped information with other data
and acts as analytical tool for research and
decision making. During the past few decades,
technological advances in the fi eld of satellite
RS sensors, computerised mapping techniques,
global positioning system (GPS) and GIS have
enhanced the ability to capture more detailed
and timely information about the natural
resources at various scales catering to the needs
of studies at the local, regional, national and
global levels.
26 Habitat Mapping of the Wetlands on GIS Platform