2
GeoMTGM: A Graphical Data Model
for Semistructured, Geographical, and Temporal Data
Carlo Combi, Sara Migliorini, Barbara Oliboni, and Alberto Belussi
University of Verona, Verona (Italy)
2.1 Introduction
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:
• One or more spatial attributes. They describe the location, shape, orientation,
and size of the object in 2D or 3D space.
• A set of descriptive or thematic attributes. These attributes provide a description
of the object, for example, the population of a country.
GeoMTGM: A Graphical Data Model
for Semistructured, Geographical, and Temporal Data
Carlo Combi, Sara Migliorini, Barbara Oliboni, and Alberto Belussi
University of Verona, Verona (Italy)
2.1 Introduction
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:
• One or more spatial attributes. They describe the location, shape, orientation,
and size of the object in 2D or 3D space.
• A set of descriptive or thematic attributes. These attributes provide a description
of the object, for example, the population of a country.