Dynamic monitoring of coastline can provide theoretical support for coastal belt protection, coastal resource development, utilization, and decision support in sustainable development. Based on the Landsat and GF-1 series satellite images covering Lianyungang City from 1973 to 2017, the paper extracts the coastline information by coastline classification system, and analyzes the evolution characteristics of the coastline and its causes. The results show: 1) In 2017, the total length of the coastline in Lianyungang City was 205.90km. The main types of coastlines were construction dikes and port coastline. The total length of the two types of coastline was 120.52km, accounting for 58.53% of the total coastline length. 2) From 1973 to 2017, the length of the coastline of Lianyungang City showed an overall growth trend. During the 44 years, the length of the coastline increased by 57.17km, with an annual growth rate of about 1.3km/a. 3) The main types of the coastline changes in Lianyungang City were silty silt coastline, biological coastline, port coastline, construction dike and Yantian dike during the 44 years. 4) In 2017, the length of the natural coastline of Lianyungang City was 69.15km, accounting for 33.6% of the total coastline length. During the 44 years, the length of the natural coastline decreased by 28.8km, and the annual reduction rate was 0.65km/a. The main reasons for the reduction of natural coastlines are the development of aquaculture, urban expansion and port construction. |