Objective  The coastal zone is where terrestrial and marine environments mutually interact. The research on landscape in coastal zone can be traced back to the 1980s, with early researchers being dominated by American and Australian scholars. After the year 2010, China also entered a period of rapid development in relevant academic arenas. It is believed that coastal zone will continue to play a critical role in coping with climate change, maintaining ecological pattern, activating land-sea interaction, presenting landscape identity, and sustaining urban public life. China has a long coastline of over 33,000 kilometers, which has obvious features and great potential for future development. Driven by the rise of land-sea integration, the implementation of territorial spatial planning and the complete ban on offshore aquaculture, the research on landscape in coastal zone in China has therefore entered a new stage that especially emphasizes the ecological, economic, cultural and aesthetic values of landscape in coastal zone. It is now necessary to conduct a systematic review of domestic and foreign researches in the past 40 years, so as to clarify the core direction and key needs of future research.

Methods  By the semantic segmentation technology based on deep learning, this research conducts a thematic cluster analysis and in-depth reading analysis of over 1,000 domestic and foreign literature on related topics, which are mainly selected from China National Knowledge Network (CNKI) and Web of Science (WoS) using keywords “coastal landscape”, with 820 English literature and 186 Chinese literature being identified closely related. Due to a large amount of literature selected, the research firstly sorts, classifies and summarizes the key themes in existing evidence based on semantic segmentation and cluster analysis, and then adopts the documental analysis method to discuss the development history, trends and hot topics of the research on landscape in coastal zone based on the results of thematic cluster analysis.

Results  The results of cluster analysis suggest that foreign literature can roughly be classified into two levels of themes. Level-I themes include the three categories of ecological protection, planning and design management, and model and method research. The category of ecological protection can be further divided into three sub-categories: disaster prevention, landscape ecological pattern and ecological protection and management. The category of planning and design management can also be divided into three sub-categories: urban development, landscape character and landscape perception. There is no secondary classification of model and method research. Thus, there is a total of six Level-II themes for English literature. The classification results of Chinese literature also show that there are two levels of themes. Level-I themes are the same as English literature, while there is a total of 12 Level-II themes: landscape ecology, disaster prevention, coastal zone management, landscape character, public space, coastal tourism and resource, coastal urban development, design and strategy, land-sea integration, coastal zone culture, and landscape resource evaluation and protection. In addition, it is found that over the past 40 years, the focus of the research on landscape in coastal zone years have been shifted from coping with urgent issues such as climate change and maintaining ecosystem stability to preserving the natural ecology and the economic, cultural and landscape values of coastal zones in response to the human-oriented paradigm. In general, there are three obvious development trends. First, coastal zone resilience, ecological pattern and conservation management have become research hotspots since the 1980s and have developed steadily ever since. They will continue to be the core topics in the field of landscape in coastal zone for a long time, and a sound theoretical and practical basis has been formed for relevant research. Besides, the protection and spatial quality optimization of landscape in coastal zone have become emerging focuses with the development of human-oriented paradigm, but to date, most of them are theoretical attempts with only a few countries trying to incorporate them into practical planning and management. In addition, territorial spatial planning led by the idea of land-sea integration has been studied intensively after 2012 and soon became an essential part of the research system for sustainable development of coastal zone. However, a unified and complete theoretical framework has not yet been established and all related efforts are still in the initial stage.

Conclusion  Through a discussion-based review, this research identifies underlying tendency changes and proposes future development paths for the research on landscape in coastal zone in China. To sum up, the research on landscape in coastal zone in China should actively respond to the global crisis of climate change and explore the characteristics of a reasonable development path that is in line with local development needs in the future. Research results suggest that the problems caused by global climate change should be put in the first place. Also, the protection and prominence of local landscape characters should be preserved to better serve the needs of creating high-quality coastal spaces. In addition, the theoretical and practical application of land-sea integration strategy should be promoted simultaneously to achieve the long-term goal of sustainable coastal development.