Extracting Trajectories with the Map Cube Operator

Abstract

OLAP (On Line Analytical Processing) is a set of techniques and operators to facilitate the analysis of data that are usually stored in a specialized database known as data warehouse. Data is analyzed in order to provide information about a particular business subject called fact, for example, crimes, sales, shipments, among others. In this paper, we extend the functionality of an OLAP operator, known as map cube, with the definition and incorporation of a function called Trajectory. This function allows the analysts extract the trajectory followed by a set of facts. For example, the trajectory of crimes of each suspect, starting from his/her oldest crime to his/her more recent one. In order to prove the expediency of our proposal, we developed a prototype that was applied to a case study of crimes in Pennsylvania. Although more extensive experiments are required, our results show patterns that can help to understand the modus operandi of suspects.

Lupa espacio-temporal: Una herramienta para el análisis visual de trayectorias en una bodega de datos

“…Dadas n columnas de agrupamiento, map cube genera en un mapa los subtotales de las medidas numéricas y espaciales (estas son agregadas mediante la función unión geométrica) para todas las posibles combinaciones de estas columnas, i. e., 2n subtotales. Moreno et al [31] extendieron este operador con diferentes funciones de agregación espacial y en [32] Moreno et al lo extendieron para la generación de trayectorias a partir de un conjunto de hechos (p. ej. el orden cronológico de los crímenes cometidos por un mismo individuo genera una trayectoria).…”