Environmental Impact Assessment is the systematic identification and evaluation of the potential impacts (effects) of proposed projects plans, programmes or legislative actions on the total environment. EIA identifies methods to minimize the adverse impacts to improve the project viability. Environmental Impact Assessment (EIA) considers land use, land price, population density, socio-economic level, road accessibility, railway accessibility, air quality, ground water quality, noise level, biological content, historical value, archaeological and visual importance etc.
RS
and GIS are ideal
tools for environmental monitoring.
Remote
Sensing and Geographical Information System (GIS) are the latest technologies or
support systems or tools which will produce much more accurate results and
perform various geographic analyses even in complex situations.
Remote
Sensing and GIS technique
is more comfortable, easy and accurate and complete the EIA of any proposed
developmental activity in less time. GIS and remote sensing could be used in environmental
monitoring for land use analysis, wetland assessment and ground water
modelling, habitat mapping, disaster management
Remote sensing is the art and science of making
measurements of the earth using sensors on airplanes or satellites.
Remote
sensing is the
acquisition of information about an object or phenomenon without making
physical contact with the object and thus in contrast to on-site observation.
Remote
sensing is used in numerous fields, including geography, land surveying and
most Earth Science disciplines (for example, hydrology, ecology, oceanography,
glaciology, geology); it also has military, intelligence, commercial, economic,
planning, and humanitarian applications.
Remote
sensed imagery is
integrated within a GIS.
Geographic
information system or GIS
is a system designed to capture, store, manipulate, analyze, manage, and
present spatial or geographic data.
GIS
has many applications related to engineering, planning, management,
transport/logistics, insurance, telecommunications, and business.
Remote
Sensing
Science
and art of acquiring information (spectral, spatial, and temporal) about
material objects, area, or phenomenon, without coming into physical contact
with the objects, or area, or phenomenon under investigation. It is important
in acquiring data for effective resource management and can be applied to
environment monitoring and management. It can be used for acquiring data in
more efficient way which is beneficial in quick change detection and
effective resource management.
Remote
sensing, is the process of inferring surface parameters from measurements of the
electromagnetic radiation (EMR) from the Earth’s surface. This EMR can either
be reflected or emitted from the Earth’s surface. In other words, remote
sensing is detecting and measuring electromagnetic (EM) energy emanating or
reflected from distant objects made of various materials, so that we can
identify and categorize these objects.
Remote
sensing provides a
means of observing large areas and has extensive applications in environmental
monitoring, urban planning, civil engineering, disaster management services
such as flood and drought warning and monitoring, damage assessment in case of
natural calamities, etc.
Principles
of Remote Sensing
Different
objects reflect or emit different amounts of energy in different bands of the
electromagnetic spectrum. The amount of energy reflected or emitted depends on
the properties of both the material and the incident energy. Detection and
discrimination of objects or surface features is done by studying the reflected
or emitted electromagnetic radiation from the object. A “sensor” (e.g.,
cameras and scanners) mounted on a “platform” (e.g., aircrafts and
satellites) detects the reflected or emitted electro-magnetic radiation from an
object. Data acquired by RS is interpreted with the help of GIS software‘s.
•
data collection from a sensor
mounted on a platform eg. a satellite;
•
data handling;
•
data interpretation which end up
in producing some thematic maps of the investigated surfaces.
Main stages in remote sensing are:
A.
Emission of electromagnetic radiation · The Sun or an EMR source located
on the platform
B.
Transmission of energy from the source to the object ·
Absorption and scattering of the EMR while transmission
C.
Interaction of EMR with the object and subsequent reflection and emission
D.
Transmission of energy from the object to the sensor
E.
Recording of energy by the sensor · Photographic or non-photographic
sensors
F.
Transmission of the recorded information to the ground station
G.
Processing of the data into digital or hard copy image
H.
Analysis of data
Passive/
Active Remote Sensing
Depending on the source of electromagnetic energy, remote sensing can be classified as passive or active remote sensing.
Sun is the naturally available source of energy in passive remote sensing. Most of the remote sensing systems work in passive mode using solar energy as the source of EMR. Solar energy reflected by the targets at specific wavelength bands are recorded using sensors onboard air-borne or space borne platforms.
In the case of active remote
sensing, energy is generated and sent from the remote sensing platform towards
the targets. The energy reflected back from the targets are recorded using
sensors onboard the remote sensing platform. Most of the microwave remote
sensing is done through active remote sensing.
Remote
sensing platforms
Remote
sensing platforms can be placed at different elevations from the Earth’s
surface and are classified accordingly:
· Ground level remote sensing
- Ground level remote sensors are very close to the ground. They are used to
develop and calibrate sensors for different features on the Earth’s surface.
· Aerial remote sensing
o
Low altitude aerial remote sensing
o
High altitude aerial remote sensing
· Space borne remote sensing
o
Space shuttles
o
Polar orbiting satellites
o
Geo-stationary satellites
From
each of these platforms, remote sensing can be done either in passive or active
mode
Advantages
of remote sensing are:
a)
Provides data of large areas
b)
Provides data of very remote and inaccessible regions
c)
Can obtain imagery of any area over a continuous period of time through which
the any anthropogenic or natural changes in the landscape can be analyzed
d)
Relatively inexpensive than employing a team of surveyors
e)
Easy and rapid collection of data
f)
Rapid production of maps for interpretation
Disadvantages
of remote sensing
are:
a)
The interpretation of imagery requires a certain skill level
b)
Needs cross verification with ground (field) survey data
c)
Data from multiple sources may create confusion
d)
Objects can be misclassified or confused
e)
Distortions may occur in an image due to the relative motion of sensor and
source
A geographic information system
captures, stores, analyses, manages and presents data, which is linked to
locations or having spatial distribution. Functions of GIS include data entry,
display, management, information retrieval and analysis. A system of hardware,
software and procedures to facilitate the management, manipulation, analysis,
modelling, representation, display of geo-reference data to solve complex
problems regarding planning and management of resources.
It is a computer-based system that
provides four sets of capabilities to handle geo-reference data, such are:
•
data
capture: graphic
data by digitization or data loaded from existing data files
•
data
storage and manipulation:
file management and editing
•
data
analysis: database
query, spatial analysis and modelling
•
data
display: maps and
reports
GIS
is becoming simpler to use and much cheaper to buy that it is hard to imagine a
future for environmental monitoring systems without it. GIS is a tool for
management, manipulation, analysis, modelling, representation of geographical
information recorded with the help of RS.
Data entry, data display, data
management, information retrieval, and analysis are the functions of GIS.
Data acquisition is the process of identifying and collecting the data required for the application. After data acquisition, the methods used to convert a dataset into a suitable format for input into the GIS is known as pre-processing.
Preprocessing is the data format conversion- digitization of maps and printed records and recording this data into a computer database; map projection, data reduction and generalization, error detection, and interpolation. Data sets are manipulated before and after entering into the computer to have a common geometric coordinate, orientation and scale.
GIS software‘s e.g; ERDAS, ArcView, ArcGIS, SWAT -improves image quality, overlapping etc. The datasets can be manipulated as needed by the analysis.
Many types of analyses are feasible
within a GIS; mathematical combinations of layers and complex simulations using
the GIS as a database.
•
Final
output of GIS is fully classified map or image which is easy to
understand.
• Geographical
Information System (GIS), is composition of traditional sciences,
contemporary science and technology.
•
A
GIS can manage different data types occupying the same geographic space.
•
The
major advantage of GIS is that it can read and analyze different layers of
information in the form of maps and satellite images easily and allows
identifying the spatial relationships.
Advantages
of GIS
On
the basis of GIS,
•
the
digital data base is developed and can be used in future and any related
information can be extracted conveniently and efficiently.
•
New
information overlaps can
be incorporated with newly defined condition.
•
GIS
is a powerful tool for handling data collected from a variety of sources
at different scales and resolution.
•
Large
quantities of data can be stored, maintained and retrieved with a
greater speed and low cost.
•
GIS
is extremely helpful in planning scenarios, decision models and interactive
processes
•
Remotely
sensed data used for resource mapping, monitoring and management.
Applications of Remote Sensing & Geographical Information System
1.
GIS is effectively used in the management of spaces for different housing
projects. Space management which is a major issue concerning the
provision of limited space to meet housing goals, minimize operating costs and
promote an effective and productive environment.
2.
The suitable site selection is the primary and essential part of
eco-city/housing projects planning. GIS can be utilized to visualize whether a
particular site meets the predefined criterions or not. GIS techniques help to
generate several important functional maps for the master plan such as the
location of the waste management sites, green space, parks and open areas etc.
3.
Housing and construction industry is one of the major sources for Green
House Gas (GHG) emission. GIS technique helps in monitoring GHG emission from
the construction activities. The maps generated from several sources could be
overlaid to prepare the emission scenario and its impact on settlements.
4.
Many applications are enhanced by the use of 3-D spatial information,
such as visualization of planning development proposals, flood predictions,
tourist visit simulations and the design of transportation networks.
Some GIS software also predicts the future growth with the help of modelling techniques. The applications of remote sensing and GIS in Environmental Impact Assessments are numerous including environmental impact and compliance studies, site investigations and characterizations, emergency planning, monitoring, transportation, telecommunication site, and water and power plant site selection etc.
1. Flooding, environmental
degradation and climate studies.
2. Agriculture and Precision
Farming.
3. In the Health Sector and
Paramedics.
4. In the Mining and Extractive
Industry
5. City planning, Transportation,
Communication Network designs and in Aviation Industry.
6. Traffic and Accident control and
prevention.
7. Planning and Re -Planning
program (Slum Re-settlement).
8. Crime Mapping and hot-spots
delineations.
9. Land use and Land cover Studies
for sustainability.
10. General Developmental control
and resource inventory and allocations.
11. Emergency planning and
alternative route development.
12. Development of agronomical data
and early warning data for food security issues.
13. Deforestation and A forestation
studies and preservation of wild life and biodiversity.
14. Engineering mapping
15. Surface water mapping
16. Land use planning and
management
17. Environmental impact studies
18. Natural resource mapping
19. coastal zone management
20. In irrigation
21. In air, water, noise, and soil
management and planning
22. solid waste disposal etc
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