A visual analysis system for exploring passenger flow information at multiple levels

In this paper, based on Smart Card Data (SCD), bus stations data and bus lines data, we present an interactive system to visually analyze the urban passenger flow. These knowledge derived from our system can help users perceive the possible traffic congestion. It is different from the previous studies which focus on detecting congestion based on car speed. Our visual analysis work consists of two phases. The first phase is preprocessing, in which we develop strategies to clean the SCD and aggregate it with the other input data to derive passenger flow information in spatial-temporal space. The second phase is visual exploration, in which we make exploration and analysis in several views of multiple levels. Firstly, we explore the passenger flow of road segments in city level; secondly, we explore the passenger flow of bus stations within a whole day in bus line level and bus station level; thirdly, we analyze the travel patterns of passengers. Case studies with the SCD collected in Beijing On August 7, 2015 demonstrate the effectiveness of our system.