Abstract: Trajectory data are increasingly becoming available to researchers due to the advances in technologies like GPS,RFID,and wireless communication devices.Mining or analyzing trajectory data is important in many different applications such as transportation management,mobility study,route suggestion,and mobile communication management.However,as trajectory data contain both spatial and temporal attributes and are often huge in size and high in dimensionality,trajectory data analysis is a very challenging task.Visual analytics solutions show great potential as they can intuitively present multidimensional spatio-temporal trajectory data and provide rich interactions,allowing users to explore the data and improve mining processes and results.In this survey,we first introduce the research problem and summarize key challenges in the visual analysis of trajectories.Then we continue with some background knowledge on trajectory data including data characteristics,collection,processing,and calibration.After that we summarize typical trajectory analysis methods,related visual presentations,and interactive system frameworks.Major visualization techniques for trajectories will be reviewed and discussed in the following section.Then we present state-of-the-art applications such as transportation management,mobility intelligence of drivers,and route suggestion.Finally,we conclude our survey with several future research directions.