Spatiotemporal Data Warehouses

Synonyms

Spatio-temporal online analytical processing; Spatio-Temporal OLAP

Definition

Consider Nregions R₁, R₂,…,R_N and a time axis consisting of discrete timestamps 1, 2,…,T, where T represents the total number of recorded timestamps (i.e., the length of history). The position and area of a region R_i may vary along with time, and its extent at timestamp t is denoted as R_i (t). Each region carries a set of measures R_i (t).ms, also called the aggregate data of R_i (t). The measures of regions change asynchronously with their extents. In other words, the measure of R_i (1 ≤ i ≤ N) may change at a timestamp t (i.e., R_i (t).ms ≠ R_i (t − 1).ms), while its extent remains the same (i.e., ${R}_i(t) = {R}_i\left(t-1\right)$), and vice versa.

A spatio-temporal data warehouse stores the above information, and efficiently answers the spatio-temporal window aggregate query, which specifies an area q_R and a time interval q_T of continuous timestamps. The goal is to return the aggregated measure Agg(...