A Semantics Associated Model for Trajectory-directed Line Movement and Its SQL Analysis

Trajectories move relative to directed lines, incurring topological events of various kinds, such as entries, departures, crosses, meets, retracements, stops and so on. Based on the spatial-temporal characteristics of trajectory-directed line movements a semantic associated model of trajectory-directed line movement is proposed, Our strategy depicts complex detailed topological relations between trajectories and directed lines by combining sets of local topological relations. In this way, movements of trajectories with respect to directed lines can be specified from the perspective of both topology and semantics. A relational schema based on this model was designed and evaluated in for two cases of typical queries types and analyzing trajectory-directed line movement by exploring pure SQL statements.