Cars, aircraft, mobile cell phones, ships, tanks, and mobile robots all have the common property that they are moving objects. A kinematic representation can be used to describe the location of these objects as a function of time. For example, a moving point can be represented by the function p ( t ) = x → 0 + ( t - t 0 ) v → , where x → 0 is the start location, t 0 is the start time, and v → is its velocity vector. Instead of storing the location of the object at a given time in a database, the coefficients of the function are stored. When an object's behavior changes enough so that the function describing its location is no longer accurate, the function coefficients for the object are updated. Because the location of each object is represented as a function of time, spatial query results can change even when no transactions update the database. We present efficient algorithms to maintain k -nearest neighbor, and spatial join queries in this domain as time advances and updates occur. We assume no previous knowledge of what the updates will be before they occur. We experimentally compare these new algorithms with more straight forward adaptations of previous work to support updates. Experiments are conducted using synthetic uniformly distributed data, and real aircraft flight data. The primary metric of comparison is the number of I/O disk accesses needed to maintain the query results and the supporting data structures.

Moving object databases store and process data for objects that change location frequently. Materialized views maintained over time must be updated to reflect changes due to the motion of objects in their environment. To visualize view query results, displays must be updated to reflect the change. In this paper we present the Internet Spatial Spreadsheet (ISS) as a means to organize, query, and visualize changing spatial data in a network environment such as the Internet.The goal of the ISS is to keep client visualizations of query results up to date with the server state. This is accomplished by pushing the minimal set of spatial data needed for rendering query results on the client. Incremental changes to query results are subsequently transmitted to the client as the database is updated to keep the visualization current. Additional constraints in the network environment such as firewall limitations are also considered.