- 55 - 3.1. General The objective of methodology is to gain familiarity with a phenomenon to achieve new insights, to portray accurately the characteristics of a phenomenon, situation or a group, to determine the frequency with which something occurs or with which it is associated with something else, and to test a hypothesis of a causal relationship between variables. Data collection describes the process of preparing and collecting all the related information for the study. The data processing deals with processing the obtained data and an important process of a scientific study. All spatial and non-spatial information have to be carefully processed by using latest geo-processing tools and programs with a structured execution of valid tools to formulate accurate, effective and useful findings. This chapter deals with the collection and processing of different types of data for the study of quantitative analysis of coastal landform dynamics using remote sensing and Geographic Information System (GIS). In this research work, the methodology has four major stages. The first stage involves with the collection of primary data such as topographical maps, aerial photograph, local maps and other related information. The second stage involves with the collection of beach profile survey data using sophisticated survey equipments. Selected beaches have been surveyed and monitored with a regular interval of time and the profile data is processed to predict the morphological and volumetric parameters of beaches. The littoral environmental observation (LEO) has been carried out in this stage. The near shore and swell (deep water) wave data are processed to predict the sediment transport along the beaches. The third stage is to obtain the remote sensing data and to process it for finding the shoreline changes and dynamics of coastal landforms. The final stage is devoted to integrate all the extracted information together to develop a web-based coastal GIS. Thus the results and finding on the dynamics of coastal landforms along the study area are shared and disseminated to the scientific community.
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3.1. General
The objective of methodology is to gain familiarity with a phenomenon to achieve
new insights, to portray accurately the characteristics of a phenomenon, situation or a
group, to determine the frequency with which something occurs or with which it is
associated with something else, and to test a hypothesis of a causal relationship between
variables. Data collection describes the process of preparing and collecting all the related
information for the study. The data processing deals with processing the obtained data
and an important process of a scientific study. All spatial and non-spatial information
have to be carefully processed by using latest geo-processing tools and programs with a
structured execution of valid tools to formulate accurate, effective and useful findings.
This chapter deals with the collection and processing of different types of data for
the study of quantitative analysis of coastal landform dynamics using remote sensing and
Geographic Information System (GIS). In this research work, the methodology has four
major stages. The first stage involves with the collection of primary data such as
topographical maps, aerial photograph, local maps and other related information. The
second stage involves with the collection of beach profile survey data using sophisticated
survey equipments. Selected beaches have been surveyed and monitored with a regular
interval of time and the profile data is processed to predict the morphological and
volumetric parameters of beaches. The littoral environmental observation (LEO) has been
carried out in this stage. The near shore and swell (deep water) wave data are processed to
predict the sediment transport along the beaches. The third stage is to obtain the remote
sensing data and to process it for finding the shoreline changes and dynamics of coastal
landforms. The final stage is devoted to integrate all the extracted information together to
develop a web-based coastal GIS. Thus the results and finding on the dynamics of coastal
landforms along the study area are shared and disseminated to the scientific community.
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3.2. Spatial and Non-Spatial Data
3.2.1. Secondary Data
a) Topographical Maps: A topographical map is a type of map characterized by large-
scale detail and quantitative representation of earth relief, usually using contour lines in
modern mapping. It is also defined as a detailed and accurate graphic representation of
cultural, natural and manmade features on the surface of earth. Topographical maps
simply called ‗Toposheet‘ have wide application in all fields such as planning, resource
management and exploitation, recreational activities etc. The Survey of India (SOI) is the
India‘s central engineering agency in charge of mapping and surveying set up in 1767.
The SOI maps are generated for a ground size of 15° × 15° in different scales with
polygonic projection and Everest 1830 as datum. The paper format of these maps (Sheet
Nos. 58-H/12, 58-H/15, 58-H/16, 58-L/1, 58-L/2, 58-L/3, Period-1969) with 1:50000
scale are scanned by using an A0 scanner and saved as TIFF and JPEG image format.
b) Aerial Photographs: An aerial photograph is any photograph taken from an airborne
vehicle (aircraft, balloons, satellites etc.). The aerial photograph has wide applications
and advantages. So, they are also used to identify the coastal landforms along the coast.
c) Local Maps: The local district maps are needed to locate the geographic boundaries of
districts, coastal villages and important landform features. The maps such as road map,
vegetation map, irrigation map are also useful to extract the information about the study
area. So these maps are also obtained from the local government authorities and scanned
and saved as TIFF and JPEG image format. The attributes of both spatial and non-spatial
information of all geographic features along the coastal area are collected and they are
used to produce the coastal geo-database.
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d) Field Visits and Ground Survey: Regular filed visits are performed to familiar with
the study area. Hand held Trimble GPS receivers are used to locate and identify the
various coastal features. The coastal landforms such as sand dunes, spits, beaches, sand
bars, estuaries, mud flats are visited and their significances are discussed with colleagues.
The dimension and significances of features are noted and used to produce the attributes.
3.2.2. Beach Profile Survey Data
a) Survey Sites: The selection of beaches for performing profile survey is based on the
geological and environmental aspects. Beaches nearer to recreational and developmental
projects, beaches with complex morphology, beaches with sand dunes, and beaches with
mining sites are selected for the beach profile analysis (12 Beaches-Figure 1.3). The
Kanyakumari beach is influenced by tourism and developments. Headlands are present
along the beaches of Manappad, Tiruchendur. The coast of Navaladi, Ovari and
Periathalai have sand dunes with a maximum height of 67 m and sand mining is actively
pursued along the coasts. Breakwater has been constructed in Koottapuli and Periathalai.
The Perumanal coast has an estuary and the sediments from Hanuman Nathi are deposited
along the beaches. The Tuticorin coast has many features and it is a major port of India.
b) Methods and Data Acquisition: The beach profile survey is the process of making
simple datasets with successive elevation and distance from a reference starting point in a
beach towards the off-shore. It can be easily performed through simple and sophisticated
methods. Several techniques are available to perform the beach profile survey. The rod
and transit (Surveyor‘s level) is a conventional and very adequate method used in
performing beach profile surveys (Parson, 1997). Krause, (2004) also insisted the
effectiveness and accuracy of this conventional and traditional profile survey method.
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Figure 3.1 Beach Profile Survey using Level and Staff
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In this present study the beaches are surveyed by using a Surveyor‘ level (Figure
3.1) for a period of two years (Mar.2006 to Feb.2008). First a narrow transect along the
beach was choused. A transect has a reference point (bench mark) whose elevation from a
reference datum is known. The profiling can be started from this reference point behind to
sub-tidal platform along the shore normal transect.
The level is placed on the reference point and the graduated staff is held vertically
at a known distance. By using the level and staff, the back-sight (BS) and intermediate
sight (IS) values are noted. Now the reading staff is moved to the next segment to read the
second intermediate sight value. Profiling has been done at regular interval of distances
from this reference point along a straight line and finally the fore-sight value (FS) is also
noted. If the beach terrain is complex and more undulating, then the level is shifted to two
or more change points (CP). The survey has been done up to a maximum low water line
of the coast covering the entire beach including berm, high tide, mid tide and low tide
zones. A compass and a GPS receiver have also been used to locate the exact location for
repeated measurements of the survey. By using this method, the beaches are surveyed and
the survey data has been recorded in the field book (Annexure A1).
3.2.3. Wave Data
a) Swell Wave Data: The deep water wave data is provided by the National Institute of
Oceanography (NIO), India (http://www.incois.gov.in/Incois/osf_coastal.jsp). The NIO
has deployed many directional wave rider buoys along the Indian coast. The wave data
including the wave height and direction for the study area has also been collected.
b) Near-Shore Wave Data: The Littoral Environment Observation (LEO) Program was
instituted by Coastal Engineering Research Center (CERC) during 1968 to provide low-
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cost data on waves, currents, and sand movements along beaches. The data collected from
the LEO program has been beneficial for design and monitoring of numerous projects
(Schneider 1981, Smith and Wagner 1991). The LEO has also been used by many
researchers to monitor the coastal processes along the Indian coast (Jena and
Chandramohan, 1997, 2001; Jeyakumar et al., 2004). In this present work, the LEO
observation was carried out for a period of two years (From Mar.2006 to Feb.2008) at the
12 beaches (Figure 1.3). The parameters such as breaking wave height and breaking
angle were measured during every month by using the above CERC procedure.
3.2.4. Remote Sensing Data
Optical Remote Sensing data such as Landsat TM and IRS 1C- LISS-III are
complimentary to coastal and marine information extraction at a particular time and
monitoring changes over a given period (Lillysand & Keifer, 2000). It provides the
excellent information about coastal landforms and shoreline changes. The present
research uses both IRS and Landsat data imageries (Table 3.1).
a) IRS Satellite Data: The Indian Remote Sensing satellites (IRS) data has been used as
the prime source for delineation of shorelines and to map the various coastal landforms
along the study area. The IRS satellites are a series of Earth Observation satellites, built,
launched and maintained by Indian Space Research Organisation (ISRO). IRS satellite
data are used for various applications such as resources management, Drought
monitoring, urban planning, coastal studies, land use and land cover mapping etc. For this
present work, the radiometrically corrected standard product of multi-date IRS-LISS III
satellite data (1999, 2006) with a cloud cover of less than 10% are obtained from NRSA.
Nayak (2002) insists the importance of low tide satellite data for shoreline mapping. So in
order to eliminate the influence of tidal variations and to get a clear demarcation of both
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low and high water levels, satellite data during low tide with same period have been used.
b) Landsat Satellite Data: The Landsat Program is a series of earth-observing satellite
missions jointly managed by NASA and the U.S. Geological Survey (USGS). Landsat
satellites have taken specialized digital imageries of Earth‘s surfaces for over three
decades; which enable to study many aspects of our planet earth and to evaluate the
dynamic changes caused by both natural processes and human practices. Multi-date
Landsat 7 ETM + satellite data with a cloud cover of less than 10% has also been used for
the research.
c) SRTM - DEM: The NASA‘s Shuttle Radar Topographic Mission (SRTM) provides
digital elevation data (DEM) for over 80% of the globe. SRTM consisted of a specially
modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day
mission in Feb.2000. The SRTM data is available as 3 arc second (approx. 90m
resolution) DEM‘s. This elevation data has been downloaded from the National Map
Seamless Data Distribution System and utilised for identifying the coastal landforms.
Table 3.1 Characteristics of Satellite Data
Sr.
No. Data Characteristics IRS LANDSAT
1 Sensor LISS III ETM +
2 Spatial Resolution 23.5 m 30 m (Visible & IR)
3 Swath 141 km 185 km
4 Repetivity 25 days 16 days
5 Coverage 141×141 km 185×185 km
6 Spectral Bands
Band-1 Visible
Band-2 Visible
Band-3 - NIR
Band-4 - SWIR
Band -1,2,3 Visible
Band -4,5,7 Reflected IR
Band -6 Thermal IR
Band -8 PAN
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3.3. Data Processing and Methodology
3.3.1. Design, Development and Execution of Computer Program
and Beach Profile Analysis
a) Beach Profile Analysis: Several software programs are available to perform the beach
profile data analysis. Majority of them are location based and analyses the data obtained
of specific beaches alone. Only few programs like Beach Profile Analysis System