Digital Methods for Construction of Shan-Shui City in Combination with Local Geographical Conditions: A Case Study of the Areas along Both Banks of the Qiantang River in Hangzhou

<sec><title>Objective</title> “Urban construction in combination with local geographical conditions” is a unique construction wisdom formed in the practice of urban construction in China since ancient times, which means selecting urban construction forms that are compatible with natural elements such as mountain topography and water patterns, ecological green corridors, and climatic conditions, based on a thorough investigation of such elements, with a focus on the harmonious relationship between man and land, and man and nature. As for how to inherit and carry forward the traditional practical wisdom of urban construction in combination with local geographical conditions in the modern city construction, the current academic research can be divided into three aspects: Shan-Shui city construction focusing on the relationship between city and nature, man-land relationship coordination focusing on the relationship between man and nature, and spatial gene recognition based on the interpretation of city history. However, such research primarily identifies spatial genes from the perspective of history, landscape space, etc., which is ultimately a kind of qualitative summary of experience and model generalization. How to accurately identify the genes of a city from its complex morphological patterns and embed them in the process of urban construction in combination with local geographical conditions needs more detailed and scientific quantitative means to achieve. </sec><sec><title>Methods</title> In the context of the era of big data, while studying and interpreting the wisdom of the traditional urban construction in combination with local geographical conditions, it is also necessary to explore how to use digital technology to inherit and innovate the traditional method. This research explores the digital method for construction of Shan-Shui cities in combination with local geographical conditions, which involves the three steps of “contextual analysis”, “corridor connection” and “shaping”. Specifically, “contextual analysis” refers to the digital sorting of landscape patterns formed by mountains and waterways, involving dividing landscape elements into different levels, identifying landscape pattern information through digital methods such as natural language processing and GIS, establishing a database, and constructing an index system including proximity index and topological connectivity for analysis; “corridor connection” refers to the digital identification and connection optimization of four types of ecological network elements, namely core protected areas, habitat patches, corridor structures, and stepping stone structures, to build a multi-level urban ecological pattern from a digital perspective; “shaping” refers to the shaping of a three-dimensional urban spatial form that connects the spatial elements of landscape pattern through digital analysis methods such as landscape viewing systems and physical environment simulation, so that the spatial elements of landscape pattern can serve urban residents as much as possible. Then the landscape pattern, habitat network and urban form of the target city are comprehensively analyzed and improved. </sec><sec><title>Results</title> This research selects the area along both banks of the Qiantang River in Hangzhou as the research area, analyzes and assesses its landscape pattern, ecological security, and urban morphology, and proposes corresponding optimization strategies. The research finds that in terms of landscape pattern, the multi-scale landscape pattern of “region – city – block” of the Qiantang River is digitally sorted out, and corresponding optimization and control strategies are proposed for the landscape pattern on both banks of the Qiantang River, involving the three aspects of mountain cluster control, water system control and landscape control. In terms of habitat network, MSPA method and GIS minimum path cost method are used to identify and extract the four kinds of natural elements of “core area, ecological batch, corridor, and island”, with a total of 5 core protected areas, 19 habitat patches, 53 ecological corridors and 42 springboard structures extracted, and plant layout, washing distribution and greening layout are optimized and adjusted. In terms of three-dimensional form, the city’s mountains and high-rise buildings are optimized through the overlooking gallery and urban skyline to highlight local characteristics. At the same time, the simulation results of wind environment, acoustic environment and thermal environment are combined to create ventilation corridors to reduce noise pollution and heat island effect. </sec><sec><title>Conclusion</title> The digital approach proposed in this research is based on the inherent characteristics of the elements of Shan-Shui cities such as mountains, waters, habitats and landscapes. It applies big data and digital technologies to the entire process of site analysis and urban planning gradually in a scientific and quantitative way, identifying the intrinsic spatial genes one by one accompanied by necessary problem analysis and optimization design, and further improving the methodological system of site analysis and urban planning. This research aims to identify the spatial genes of Shan-Shui cities in a scientific and quantifiable way, so as to provide a digital method based on traditional wisdom of site selection and city construction for contemporary urban construction, and endow the traditional city-building model with new vitality through the application of digital technology. </sec>