Exploring temporal and spatial reliability of individual activity space measurements using massive mobile phone data

Abstract

AbstractThe concept of activity spaces is widely used in various research fields, but the reliability issues of individual activity space measurements remain underexplored. In this study, we develop a modified individual activity space measurement using massive mobile phone data for a month, called the weighted confidence ellipse (WCE), to quantitatively explore the reliability issues. According to the empirical results, we determine that using individual activity–travel data accumulated over a period of at least 2 weeks to measure individual activity spaces is relatively reliable in time. If considering the independence between workdays and days‐off, individual activity–travel information for day‐offs is necessary to exceed 2 weeks. In addition, the spatial reliability of individual activity space measurements demonstrates obvious spatial continuity and heterogeneity. Spatial location is the key factor affecting individual activity space measurements, and the impacts of the separation effects of residence and workplace may deserve attention, especially in the areas with a single urban spatial structure or urban function. This study can help us to improve knowledge on the temporal and spatial reliability of individual activity space measurements, so as to provide some references for studies on related research issues.