Moving Objects Databases

Moving objects databases are particular cases of spatiotemporal databases that represent and manage changes related to the movement of objects. Unlike spatio-temporal applications associated with geographic phenomena where the identity of geographic features may change over time, in moving objects databases the objects maintain their identities but change their locations or shapes through time. That is, it is the geometric aspect of an object that changes rather than the object itself. Within this domain, the most suitable applications are those where objects are cars, airplanes, or any object with regular movements. Traditional DBMSs are not well equipped to handle data about moving objects. One of the reasons is that DBMSs assume that data is constant unless an explicit modification occurs, and this assumption is not adequate for handling continuously changing data such as the locations of moving objects. In traditional DBMSs, it is difficult to specify queries about spatial and temporal information. For example, a query such as “retrieve the cars that will intersect at a particular location in an hour” is not easily expressed with SQL. Finally, location of a moving object is inherently imprecise because the location stored in the database cannot always be the actual location of the object (Wolfson, 2002). Unlike traditional database applications, moving objects applications involve the following requirements, which are a subset of spatio-temporal applications requirements (Pfoser & Tryfona, 1998):