| Abstract: | The morphological and functional dynamics of coastlines are further complicated by the intricate interplay between land, sea, and air. Concerning coastline extraction, this study employs both human-machine interactive interpretation and focused profiling methods based on extensive multi-source data within the surrounding areas of the Nanshawan area to identify various coastlines. In recent years, the extensive application of remote sensing technology and GIS provides an important basis for the study of coastline. Based on vast amounts of open source data, this paper takes the Nanshawan as the sample area to explore extraction of different types of coastline by combining a visual interpretation method and a transect-focused approach. Integrating two methods to extract the Nansha district coastline, this study focus on analyzing the spatiotemporal evolution of the coastline of Nansha district. The results showed that: The transect-focused approach is more scientifically rigorous in identifying natural coastlines, whereas human-machine interactive interpretation based on orthophoto images of UAV and QuickBird satellite images is consistent with actual conditions. The length of the coastline experienced relatively drastic changes between 1990 and 1995, as well as between 2005 and 2012; the coastline rapidly expanded into the sea, with a rapid increase in reclamation area, before 2012,and it narrows gradually in the later stage. The results reveal that the state of the coastline during different stages of development is highly correlated with human activity. In the stage of agricultural civilization, reclamation projects of Wanqingsha Town promoted southward expansion of coastline. In the industrial development stage, development of Longxue Subdistrict further expanded coastline. In the new town construction stage, ecological restoration coastline increased while part of coastline retreated inland, achieving refined utilization of coastline. |
