城市居民活动轨迹日间稳定性分析——以西宁市为例

Analysis of inter-day stability of urban residents’activity trajectories:A case study of Xining

针对基于轨迹数据分析人类移动特征忽略日间稳定性的问题,本文以西宁市为例构建个体活动轨迹日间稳定度量方法,分析居民活动轨迹日间稳定性及其分布特征。研究表明:①不同类型天之间,居民总体有54.5%的时间位于同一位置;②工作日的日间稳定性较高;活动位置稳定性在一天中的凌晨最高,晚上次之;③青少年人群活动轨迹日间稳定性最高,高出稳定性最低的中年人群14%;④女性在工作时间活动轨迹日间稳定性略高于男性,在休息日白天有较男性更加多样化的活动位置;⑤街道尺度下,近郊区城市居民活动轨迹日间稳定性低于城中心和远郊区。

The availability of massive human trajectory data enables numerious researches and applications in human dynamics.Related results have been widely applied in urban planning,public health promoting,optimization of public facilities,etc.However,the stability of outcomes of the human mobility studies is usually ignored in existing research and applications.Therefore,understanding the inter-day stability of residents’activity trajectories is of great significance for the scientific utilization of limited location data in travel and urban planning decisions.To address this gap,this study analyzes the inter-day stability based on individual trajectories enabled by mobile phone location data.Raw individual trajectories have been interpolated based on records with the shortest time intervals to improve the usability.The location of each record has been allocated to corresponding 500-meter grids.An inter-day stability measurement is constructed based on the total distances between locations with the same timestamp between two users.We calculate and compare inter-day stability among population with different labels(e.g.,genders,ages).To describe the spatial pattern of population inter-day stability,we identify home locations based on anchor points during the night and calculate the average inter-day stability at different grids.To compare temporal patterns of inter-day stability,we divide a day into three periods:midnight(0:00-6:00),daytime(6:00-19:00)and the evening(19:00-24:00).The inter-day stability between different day types(e.g.,weekdays,weekends)is also compared.Using a four-day dataset from Xining as an example,we find that:①Residents spend an average sof 54.5%of their time in the same location between two days,indicating relatively high inter-day stability.However,considering stable time periods,including the night,implies that the“unstable”time accounts for a significant part during a day,especially during the daytime.②Inter-day stability on weekdays is relatively high,with the highest activity location stability before dawn,followed by the evening.③The activity trajectory of teenagers has the highest inter-day stability,14%higher than that of young people with the lowest stability.④Women have slightly higher inter-day stability of activity trajectories during working hours than men,but they have more diverse activity positions during holiday daylight than men.⑤The inter-day stability of activity trajectories of residents in the suburbs is lower than that in the city center and the outer suburbs at the sub-region scale.Inter-day stability exhibits complicated patterns among different populations in different locations or with different properties.The impacts on human mobility research and related applications need to be realized and well understood to avoid potential misuse of related datasets.