GeoMTGM: A Graphical Data Model for Semistructured, Geographical, and Temporal Data

A few decades ago, paper maps were the principal means to synthesize and represent geographical information. Manipulating this information was limited to a manual, non-interactive process. Since then, the rapid development of new technologies for collecting and digitizing geographical data, together with an increasing demand for both interactive manipulation and analysis of this data, has generated a need for dedicated software, namely geographical information systems (GISs) [23]. GISs have made available a large amount of geographical data to several applications, and as a consequence, spatial data have been included in different automatic tools (like, many decision support systems), providing a new dimension of analysis, represented by the common reference space: the Earth surface. Different kinds of problems can benefit of the new spatial dimension: from geomarketing to epidemiological crises. Recently, with the diffusion of XML [24] as the language for exchanging data over the Web, it has become more and more common to manage complex geographical information represented as semistructured data, that is, data having an irregular or incomplete structure that can change over time [2]. For this reason, semistructured data are often explained as “schema-less” or “self-describing,” meaning that there is no separate description of the structure of data. In this chapter, we propose a new model for semistructured data that allows one to represent multimedia and temporal aspects of geographical data described as a set of geographical objects. With the term geographical object (or feature in the Open GeoSpatial Consortium terminology), we mean an abstraction of a real-world phenomenon associated with a location on the Earth’s surface [21]. A geographical object may be characterized by the following components: