Multi-granular spatio-temporal object models : concepts and research directions

The capability of representing spatio-temporal objects is fundamental when analysing and monitoring the changes in the spatial configuration of a geographical area over a period of time. An important requirement when managing spatio-temporal objects is the support for multiple granularities. In this paper we discuss how the modelling constructs of object data models can be extended for representing and querying multi-granular spatio-temporal objects. In particular, we describe object-oriented formalizations for granularities, granules, and multi-granular values, exploring the issues of value conversions. Furthermore, we formally define an object-oriented multi-granular query language, and discuss the dynamic adapting of multi-granular data. Finally, we illustrate the current open research issues of multi-granular spatio-temporal data handling.