Land use is defined as all human or economic activities associated with a specific land pattern, while the term land cover refers to the type of feature present on the Earth's surface (Lillesand et al., 2015). One of the objectives of this work is to investigate the problems and causes of coastal land cover change. Global environmental change is clearly a unique process that deals with land use/land cover changes through the alteration of the land surface and its biotic cover.
Land use refers to the human use of the land and land cover refers to the physical and biotic character of the land surface. Not only is information on land use and land cover change relatively low at the global level, but we need a much clearer understanding of the driving forces behind these changes. The highest erosion rates around the southern part of the island are shown by different methods (Islam et al., 2014).
One of the studies was done on simulating land cover changes and their impact on land surface temperature in Dhaka (Ahmed et al., 2013). Most of the people in this area are fishermen and are largely dependent on the Bay of Bengal.
Siltation
The country has a long, dynamic, varied, straight and continuous coastline along the Cox's Bazar and Khulna area, where there are no islands to serve as windbreaks.
Geo-morphological change
Impacts of siltation on fisheries
Unsupervised classification
Supervised classification
Raw data collected from the USGS data site that maps Earth images to available geospatial data types. Data specialists, systems engineers, user service representatives, and science communicators work together to support LP DAAC activities.
Description of LULC classes
- Image pre-processing and LULC class detection
- Land Use/Land Cover Change processing of unsupervised classification Land Use Land Cover change processing had to run various successive processes
- Embellishment of final layer
- Further analysis of processed image
11 Cultivation of fish or shrimp on the island and also human interpretation or use of land for salt production during the dry season. Google Earth Pro Clear and historical imagery provided knowledge of the study area that aided in supervised classification. Using QGIS software, the shapefile of the study area was extracted from the Bangladesh imaginary using WGS84.
In this process, the layer found after using the project's raster tool was used as input. In this process, the last processed layer was used as input and before the system. Then, the names and color of all legends were changed for the map of all years in the same study area.
It helped to interpret these maps and calculate the change of changes in land use. For calculation of Land Use Land Cover Change (LULC) the final map of all years for two studied areas (Moheshkhali and Kutubdia) was used and processed.
Data Validation and Field validation
CHAPTER FOUR RESULTS
Unsupervised classification of Kutubdia and Moheshkhali .1 LULC change of Kutubdia Island
The area of each land use/cover class of the 3 distinct categories is represented by the data reported in the table. 5, the years and land classes are waste land, plantations, aquaculture, mangrove forests, salt, grass land, deciduous needle leaves. forests are included. The analysis of the changes of the entire time period in the study area provides information about the changes of three different time periods. 25 | P a g e Table 5 Area (square meter) and percentage of land use/cover classes of different time periods.
Land Use Land cover Change Of Kutubdia
The land use and land cover change analysis of the entire time period in the field of research provides information on developments in three separate periods. Plantation and mangrove have a destructive downward trend throughout those years (figure of plantation and 28.91% mangrove was decrease in Kutubdia (table 6). The conversion of the land use/cover classes from one type to another and the net change matrix of different time periods, from 2001 to 2019, significant changes have taken place.
LULC change in Kutubdia (2001-2019)
Aquaculture/ Salt Pan Deciduous Forest Mangrove Forest Permanent Wetlands Plantations Bare Land Water Bodies Grand Total. There were two major soil classes that contained a major change throughout the period of 2001-2019. The significant value (0.214) is more than 0.05 which means that null hypothesis is accepted and there is no significant correlation between Aquaculture and Mangrove Forest in Kutubdia.
In Moheshkhali, eight major land cover categories were identified in all study years and 2019, namely barren land, water bodies, plantations, aquaculture/salt pans, mangrove forests, grassland, deciduous forests and permanent wetlands. Change analysis of the entire time cycle in research provides data on developments in three different time periods. The landmass and area change rates of this island were measured without a permanent wetland.
35 | P a g e Table 9 Area (m2) and percentage of land use/cover classes of different time periods in Moheshkhali Island.
Land Use Land Cover Change of Moheshkhali
Water bodies and plantations have not undergone any obvious change, but there has been a significant amount of diversion into aquaculture. In this study, the change analysis of the entire time period provides information about changes over three different time periods. The area increased or decreased within the land class shown in Table 10.
38 | Page Table 11 presented the transfer from one type to another of the land use/cover groups and the net change matrix of different periods. Swapping area from one land class to another, giving Moheshkhali Island a significant change.
LULC change in Moheshkhali (2001-2019)
Parallelism among land classes of Kutubdia and Moheshkhali
A comparative study between Kutubdia and Moheshkhali Island on the basis of increasing aquaculture rate was carried out during this study. On the other hand, Moheshkhali contains a good amount of rising aquaculture, but it was lower than Kutubdia (Fig. 23).
Rate of Aquaculture
Moreover, in the first decade, plantation in both study areas was similar in trends, but in the last decade, from 2009 to 2019, a huge change took place. In 2019 this will reach 2%, which could pose a major threat to the ecosystem of this cyclone-prone erodible island (Fig. 25).
Rate of Plantations
Supervised Classification of Kutubdia and Moheshkhali Island
Different land classes were found after ground truth and GPS data collection of different areas. Land classes such as salt pan, mangrove, plantation and cropland crop abundantly in this area. With supervised classification of these areas, maps of different years showed a distinct change in Kutubdia and Moheshkhali. The rate of rise of the salt pan was so strong that it dominated the northeastern side of Kutubdia and the northwestern side of Moheshkhali.
Rate of Mangrove Forest
CHAPTER FIVE DISCUSSION
On the other hand, grass land and aquaculture rate, plantation, water bodies were improving from 2001 to 2019. On the plantation side, Moheshkhali has a relatively good view with an improved rate, but in Kutubdia has a loss of plantations in the last decade. This geospatial data includes not only land use and land cover (LULC) maps and locations, but also various data attributes, such as socio-economic census data.
There are different types of LULC components such as salt marshes, mangroves, grasslands, plantations, forest lands and many more. There are wide-ranging applications for LULC maps, such as natural resource management, GIS input baseline mapping, legal restrictions for property taxes and assessments, and much more. It is important to conduct research on construction, improvement of local socio-economic problems, evaluation of various environmental and biodiversity impacts to evaluate and manage the appropriate land planning to evaluate and manage updated information on different classes of land in Kutubdia and Moheshkhali Island.
Anthropogenic behaviors and, to some extent, some natural phenomena were the main controlling factors of physical and ecological changes in the different land classes of this region from 1971 to 2009 (Islam and Murshed, 2011). 50 | P a g e Rapid invasions of the salt field into the mangrove forest area are reducing the environmental balance. In the near future, the rest of the mangrove forest may also be affected by the construction of the deep-sea port at Sonadia.
The government should be responsible for promoting agricultural practices for local citizens to preserve the remaining arable land. Local citizens and local authorities should have a vital role to play in stopping these criminal activities and appropriate legislation and mitigating measures for conservation of hill forests should be enforced.
CHAPTER SIX CONCLUSION
RECOMMENDATIONS
LIMITATIONS
CHAPTER SEVEN REFERENCES
Spatial Land Use/Land Cover Changes in Moheshkhali Island, Bangladesh: A Fact Finding Approach Using Remote Sensing Analysis. Land use and land cover change detection using remote sensing approach: A case study of Kodaikanal Taluk, Tamil Nadu. Modeling spatio-temporal shoreline movement of a coastal island in Bangladesh using geospatial techniques and an extension of DSAS.
2017, Scenario-based simulation on dynamics of land use-land cover change in Punjab province, Pakistan. Climate induced vulnerability and migration of the people from islands of Bangladesh: a case study on coastal erosion of Kutubdia Island. Variations in ecosystem service values and local economy in response to land use: A case study of Wu'an, China.
Urban built-up land change detection using road density information and spectral information from multi-temporal Landsat TM data.
