Abstract
At present, China's urban construction has been transformed to the historical stage of fine adjustment and improvement, which means that the focus of urban planning and construction has begun to shift from the concept of speed first to quality pursuit, and gradually pay attention to people's life comfort and happiness in cities. In the face of urban fine design needs, there is an urgent need for a comprehensive and rapid evaluation system to evaluate the quality of street space. Thinking about the quality of street space is not new. The pioneers represented by Jacobs and Lefebvre began to discuss the spatial quality and its social and economic effects as early as 1960s. Gehl, Whyte and Lynch deeply studied the characteristics of urban space, and constantly summarized the methods to improve the quality and vitality of urban space, in which street space is the research focus. These research results are still of guiding significance for the current research, but due to the lack of quantitative basic data and evaluation index construction, it is not conducive to further assist the fine design practice and management. This paper selects the street space of Lujiazui core area with dense traffic flow in Shanghai as the research object, and uses multi-source data such as POI data, road network data, spatial morphology data, social media data and street view images to establish the basic database for quantitative evaluation of street space quality. The evaluation index system of street space quality was constructed by using spatial syntax analysis, panoramic segmentation analysis of street view images, functional clustering analysis, POI density mixing degree and heat analysis, spatial and temporal variation of population density distribution and other analysis methods. The index system relies on the two dimensions of material space composition and subjective space perception of urban street space quality, including five indicators, 18 evaluation factors in total: street space carrying capacity (construction intensity, space form, street green coverage rate, street height width ratio, street space identifiability), street space vitality (street function, street scene type analysis, street facade color analysis, business hours facing the street analysis), street environment comfort (walking convenience, landscape beauty, facilities perfection), street travel safety (street brightness, vehicle interference index, completeness of marking facilities), crowd social interaction (Baidu heat map, crowd concentration, social interface index). The evaluation results show that the richness of various service formats in Lujiazui core area in Shanghai is low, the slow traffic system is broken, the degree of street humanization is low, the street space lacks the connection between streamline and style, and the street service level does not match the high-density crowd. Then we put forward promotion strategies from three aspects of street public space, street public facilities and street support system. It is pointed out that in the street planning and design, different types of squares and commercial facilities should be set up in combination with the diversified needs of residents, so as to make the street have diversified functions, improve the accessibility of traffic and the comfort of the street environment, as well as for the purpose of accumulating popularity and making the street more energetic. In this study, the evaluation of traffic trunk roads is relatively low, but as functional roads, they fully meet the requirements. Therefore, this study is applicable to the spatial quality evaluation of living streets and has high universal applicability. At the same time, limited by data sources and research technology, this study still has some limitations. In the follow-up study, we can carry out a more comprehensive evaluation by integrating the street's own attributes.
