Introduction

Abstract

Space and time: the two axes according to which our lives are evolving. Every physical object has its own location (in space), a location that may change as time passes. This is how mobility is formed and governs our lives. Think of what ‘frozen’ time would mean; but this turns out to be philosophical discussion, which is for sure beyond the scope of this book… Database industry has for years been able to efficiently support time and space, though independently (the so-called, Spatial and Temporal Databases—SDB and TDB, respectively). However, it is obvious that these two axes of information find many interesting applications, if handled in conjunction. When we have in mind applications (e.g. cadastral systems) that consider spatial objects, which may change their shape or location discretely, from time to time, then we usually call them Spatio-Temporal Databases (STDB) whereas those that consider continuous or at least very frequent changes of objects’ locations are classified under the term Moving Object Databases (MOD). In the latter case, the main content of the database is the so-called mobility data, i.e. information about the movement of objects, which includes, at least, location and time information. In this chapter, we preview the concept of mobility data and briefly discuss what can we learn from such data collections. We summarize by discussing the transition from—stationary—spatial to mobility data management and the challenges that emerge.