建成环境对城市活力影响的时空异质性研究:基于大数据的分析

The Spatio-temporal Impacts of the Built Environment on Urban Vitality:A Study Based on Big Data

城市地理与城乡规划一直关注建成环境对城市活力的影响,但鲜有研究揭示该影响的时空异质性。城市活力表现为居民在实体空间上的分布及其活动,并呈现时间动态变化特征。通过采集广州市中心城区新浪微博签到数据以及建成环境大数据,在1 km×1 km方格网、2 h时间段的时空单元上可视化城市活力的时空动态变化特征,基于时空地理加权回归模型(GTWR)揭示区位、功能混合度与密度对城市活力影响的时空异质性,并对比工作日与双休日的差异。研究发现:(1)广州中心城区城市活力呈现东西带状的“多节点”空间格局,在24 h内经历“分散-集聚-进一步集聚-分散”的时空动态变化。(2)区位、功能混合度与密度对城市活力的边际效应表现出空间和时间双重维度的不稳定性。(3)由于居民活动的时空约束不同,城市活力时空特征及其建成环境影响在工作日与双休日存在差异。

Urban vitality reflects human activities and their interactions with spatial entities, which exhibits both spatial and temporal variations. However, the spatio-temporal variations have not been well addressed in existing research on the impacts of the built environment on urban vitality. Based on a collection of Sina Weibo check-in records and POI-based built environment data in central Guangzhou, this research visualizes the urban vitality at the scale of 1 km×1 km grid and 2 h period over one day. Geographically and temporally weighted regression(GTWR) are used to unveil the influence of location, density, and diversity on the urban vitality and their spatiotemporal heterogeneity. The difference between urban vitality and the impacts of the built environment on weekdays and on weekends have also been examined. The results show that: 1) the urban vitality in central Guangzhou extends along the east-west strip, with White Goose Pool, Beijing Road, Shangxiajiu Road,Zhuajing Newtown, Pazhou as the agglomerations. In one day, the urban vitality experiences dynamic changes from relatively scattered to agglomeration during the daytime and keep further agglomeration till midnight.2) Although the location, density, and diversity significantly influence urban vitality, their impacts vary across space and time over a 24-h period. Generally, distance to the city center is negatively associated with urban vitality, while diversity and the density of leisure, housing, transport, and other facilities are positively associated with urban vitality. 3) Due to a lower activity constraint of space and time on weekdays and on weekends, their urban vitality and the spatio-temporal impacts of the built environment are obviously different.