| Wenzhou has a vast land-sea boundary line,and the total length of the coastline is more than 300 kilometers.In the past 20 years,the coastline of Wenzhou City has been constantly changing due to the impact of human activities.The natural coastline has gradually shortened from 60% to about 30%.More than 80% of the islands have been developed and utilized.The land area directly increased by the creation of land from the sea is as high as more than 200 square kilometers.It can be seen from these that the influence of human activities is disturbing the changes of the coastal zone in a large area,and natural influence factors have become a secondary factor.The coastline is an important national land resource and a non-renewable resource.The rational use of the coastline is of great significance.However,due to problems such as the long coastline and weak human resources,problems such as the unclear status of coastline usage,the lack of knowledge of coastline changes,and the inability to quantitatively express the implementation of coastline have all appeared on the Wenzhou coastal zone.In order to find a solution,this article will use remote sensing technology to extract and analyze the temporal and spatial evolution of the coastline of Wenzhou City for 20 years,analyze the driving factors of its coastline change,the intensity of the change and other influencing factors,and provide guidance for the sustainable development and utilization of the coastline of Wenzhou City in the future.opinion.The remote sensing image sources used in this study are Landsat TM,ETM+,OLI,and are based on the Arc GIS platform and e-Cognition platform combined with remote sensing(RS)technology to extract the 20-year(2000-2019)coastline of Wenzhou City.The first phase of coastline is extracted annually,totaling 10 phases of coastline data.In this study,the interpretation marks of various types of shorelines were first established,and the latest ESP2 optimal segmentation scale tool was used to confirm the "optimal segmentation scale parameter" compared to directly confirming the segmentation scale through visual interpretation.This method makes the image segmentation accuracy.It has been greatly improved,and then used the object-oriented classification method to extract the 10 th shoreline,and calculate the length and type of the 10 th shoreline.Afterwards,the extracted ten-stage coastline is analyzed and studied on its time-space evolution on the Arc GIS platform,and its evolution process is evaluated using coastline evaluation indicators.Finally,the fractal dimension is used to analyze the intensity of the coastline transition.The study came to the following conclusions:1)During the 20 years from 2000 to 2019,the overall trend of the length of the coastline in Wenzhou City showed a state of gradually decreasing first and then slowly increasing.In 2019,the total length of the coastline of various districts and counties in Wenzhou was 970.4km.In 2000,the total length of the coastline of all districts and counties was 966.6km.Compared with the year of 2000,the coastline length increased in 19 years,and the total coastline length increased by 3.8km.The total coastline length of Cangnan County has increased by 1.92 km,Pingyang County has been shortened by2.27 km,Yongjia County has been shortened by 0.81 km,and Wenzhou City(Dongtou District,Lucheng District,Longwan District)has increased by 2.67 km,while Yueqing City and Ruian The city has increased by 0.03 km and 2.25 km respectively.2)In the past 20 years,the artificial coastline and the natural coastline have been declining.During this period,the artificial coastline has increased by 223.3km,and the natural coastline has decreased by 219.5km.After analysis,the main influencing factors are the reclamation of land from the sea and the aquaculture,which has also led to a significant decline in the maintenance rate of natural shorelines in the past 20 years.In summary,due to population growth and the acceleration of urbanization during the20-year period,human activities have gradually spread from the inland to the coastal zone,and the impact on the coastal zone has exceeded the natural factors in intensity,breadth and speed.The impact caused by the coastal zone.3)Coastline changes have increased the land area of Wenzhou by 213.05 km~2.The land area increased by 18.77 km~2 from 2000 to 2007,the land area increased by129.97 km~2 from 2007 to 2013,and the land area increased by 64.32 km~2 from 2013 to2019.4)During the 20 years from 2000 to 2019,the fractal dimension of the Wenzhou coastline has shown a downward trend on the whole,which also shows that the Wenzhou coastline has gradually changed from complex to simple during this period,and the fractal dimension has changed significantly.The shape of the shoreline has a high correlation. |
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