Time dependent geometry
A moving object is essentially a time dependent geometry. Moving objects are the entities represented and queried in moving objects databases.
The term emphasizes the fact that geometries may change continuously (whereas earlier work on spatio-temporal databases allowed only discrete changes, e.g., of land parcels). One can distinguish between moving objects for which only the time dependent position is of interest and those for which also shape and extent are relevant and may change over time. The first can be characterized as moving points, the second as moving regions. For example, moving points could represent people, vehicles (such as cars, trucks, ships or air planes), or animals. Moving regions could be hurricanes, forest fires, spread of epidemic diseases etc. Moving point data may be captured by GPS devices or RFID tags; moving region data may result from processing sequences of satellite images, for example. Moving...