关键词: 公共空间, 手机数据, 活力评价, 公园, 南京

Abstract:

The vitality of public space is an important indicator of urban quality, as urban public space is important for people to attain positive experiences from public life and social interactions. Measuring the vitality of public space faces challenges, because the vitality is a multi-dimensional and nebulous concept. Meanwhile existing approaches often focus on the scale of activity to indicate vitality but lack of a comprehensive assessment of vitality. To overcome this problem this paper aims to address this research gap by proposing a multi-dimensional framework for a holistic evaluation of the vitality of public space. Three aspects are identified, based on theories about the vitality of public space, as critical to assessing the vitality of public space, which include individual behavior, spatial activities, and spatial interaction networks. Accordingly, three measurements, including the ratio of tourists’ revisit, the degree of mixed activities, and the centrality of network interactions are proposed. Using the proposed measurements, a case study in the city of Nanjing was carried out. The vitality of 42 parks in the center city, as examples of public space, was evaluated. To measure tourists’ activities, a dataset of two weeks’ anonymous mobile phone signal records during the March 2018 was used. The results showed that the vitalities of parks are high overall, while there are significant differences among different types of parks. In particular, parks with more comprehensive functionalities tend to show higher scores of vitalities, and parks providing one or a few specific functionalities have lower vitality and the neighborhood parks are the lowest in vitality. Moreover, the three measurements indicate variety vitality of parks. For instance, the ratios of tourists’ revisit vary greatly among parks. The degree of mixed activities, in contrary, presents a cluster pattern in which most parks gained high scores. The centrality of network interactions also varies considerably among parks. A core network of parks was observed, which is composed of 22 parks such as Xuanwu Lake, Meihuashan, and Luboyuan. From a methodological perspective, an evaluation framework proposed in this study allows us to comprehensively understand and to quantitatively measure different constructs of the vitality. The measurements also provide useful insights into the design and planning of public space, as planners could optimize public space and improve the vitality based on the evaluation results. Through the higher resolution activity data, this analysis framework can be applied to analyze the vitality of small-scale space accurately, and combined with other information, such as tourists’ property and space facility, to further explore the influencing factors of space vitality.

Key words: public space, mobile phone data, vitality evaluation, park, Nanjing