Reference Work Entry

Encyclopedia of GIS

pp 662-670

Mobile Object Indexing

  • George KolliosAffiliated withDepartment of Computer Science, Boston University
  • , Vassilis TsotrasAffiliated withDepartment of Computer Science and Engineering, University of California-Riverside
  • , Dimitrios GunopulosAffiliated withDepartment of Computer Science and Engineering, University of California-Riverside

Synonyms

Spatio‐temporal index; Indexing moving objects

Definition

Consider a database that records the position of mobile objects in one and two dimensions, and following [8,13,16], assume that an object's movement can be represented (or approximated) with a linear function of time. For each object, the system stores an initial location, a starting time instant and a velocity vector (speed and direction). Therefore, the future positions of the object can be calculated, provided that the characteristics of its motion remain the same. Objects update their motion information when their speed or direction changes. It is assumed that the objects can move inside a finite domain (a line segment in one dimension or a rectangle in two). Furthermore, the system is dynamic, i. e., objects may be deleted or new objects may be inserted.

https://static-content.springer.com/image/prt%3A978-0-387-35973-1%2F16/MediaObjects/978-0-387-35973-1_16_Part_Fig22_HTML.gif
Figure 1

Trajectories and query in (t, y) plane

Let P(t0) = [x0, y0] be the initial position of an object at time t0. Then, the object st ...

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