Moving Object Databases

Moving objects are those whose position changes frequently over a period of time. Conventional databases don't know how to handle this scenario, as they assume the data objects are stationary

In this case, we use moving object databases. These databases can store information about moving objects and allow querying on them.

For example- The location of nearest taxis for a particular customer can be found using querying on moving object databases.

The approaches used in handling moving object databases are:

Location Management

The current locations of the objects are saved in the database and estimations are made on their near future positions. This information is accessed from the moving object database using queries. Past data is deleted as it is no longer useful.

An example of location management is a database storing locations of taxis in a particular locality.In this case, if the taxis frequently send data to the database, then their position in the database will be accurate but there will be too much data to handle. Conversely, if they don't send their location parameters too often, then database may contain outdated data. 

The only solution to this problem is to store the speed and direction of the moving objects in addition to their location. The near future locations can be calculated using the speed and direction and the data flow is also reduced. 

Spatio Temporal Data

The spatio temporal database stores not only the present data but also data that was collected well into the past. All of this data is used to observe patterns in a particular situation and analyze it.

Example- Stored data can be used to analyze the following scenarios −

  • Is the amazon rainforest shrinking?
  • Are the hammerhead sharks dying out?
  • Did the migratory pattern of birds change in India?

The spatio temporal data is stored in the form of points, lines, regions etc.

The spatio temporal data can be in 2 forms −

  • Moving point - Only the location of the data point matters and not its size or extent.
    Example - The location of an airplane at any given moment
  • Moving region - The location of the region as well as its size and extent matters as the region may reduce or increase with time. Example - The location and size of a hurricane as it travels across the country.