CSE 594: Spatial Data Science & Engineering Overview of Moving Object Data Arizona State University Trajectory of Moving Objects A type of spatiotemporal data generated by moving objects A trajectory is a polyline in three-dimensional space Two dimensions refer to the space and the third dimension refers to the time Represented as a sequence of position points Tr(P1, P2, …, Pn) Each position point Pi is represented as (lat, lon, t), where lat and lon are location coordinates and t is the timestamp Queries on Trajectory Data Given a dataset, a moving object id, a time range [ts, te], the query returns all the trajectory line segments of the corresponding object such that all position points Pi of the line segments have the timestamp value within the given time range If the object id is not given, return all trajectory line segments satisfying the above constraints Temporal Query Given a dataset, a spatial range {latmin, lonmin, latmax, lonmax}, the query returns all trajectory line segments such that all position points Pi of the line segments are located in the spatial range Spatial Range Query Queries on Trajectory Data Given a dataset, a spatial range {latmin, lonmin, latmax, lonmax}, and a time range [ts, te], the query returns all trajectory line segments such that all position points Pi of the line segments are within the spatial and temporal range Spatiotemporal Range Query Given a dataset, a query trajectory q, a distance function, and a distance threshold, the similarity query returns all trajectories Tri where the distance between q and Tri is not greater than the given distance threshold. Similarity Query Queries on Trajectory Data Given a dataset, a query trajectory q, a positive integer k, and a distance function, the K-NN query returns k nearest trajectories of q, where the distance from q to other trajectories is measured based on the given distance function K-NN Query Popular Moving Object Databases MobilityDB Secondo TrajMesa TrajStore MovingPandas Sci-kit mobility Libraries for Analyzing Moving Objects
