Differences in urban daytime and night block vitality based on mobile phone signaling data: A case study of Kunming’s urban district

Exploring the pattern of block vitality within cities and its influencing factors is an important topic in urban vitality research, which has great significance in promoting high-quality urban development. However, existing research has paid little attention to the spatial difference characteristics of daytime and night urban vitality and the differences in their influencing factors. Using the urban area of Kunming, China, as a case study, this study explores the differences in spatial patterns of daytime and night vitality at the intra-city block scale and analyses the differences in the main influencing factors of daytime and night block vitality using spatial regression models. The study obtains the following findings: (1) daytime block vitality in Kunming’s urban district (the urban Dist. of KM) is higher than night block vitality. The First Ring Area has the highest daytime block vitality, whereas the Second Ring Area has the highest night block vitality. (2) Block vitality in the urban Dist. of KM presents a polycentric structure. (3) There are obvious differences in the factors influencing urban vitality between daytime and night, with work accessibility, functional mixing, daily consumption accessibility, floor area ratio, and average building age, having different directions of influence on daytime and night urban vitality. (4) Daytime urban vitality in the urban Dist. of KM relies on work activities, while night urban vitality relies on residential activities. The results provide a scientific basis for urban land use layout, facility construction, and higher-quality urban planning and management, thus promoting sustainable urban development.