Logical database design

Applied Geomatics, 2009

In the framework of Land Planning and Management activities, a database including a large variety of datasets of heterogeneous typology and acquisition is fundamental in order to allow for diversified queries and efficient selection of data. Local municipalities (and unions or consortia of municipalities) in Regione Lombardia are encouraged to create their own geographical information systems (GIS) for territorial data management and to incorporate in the database the results of the nowadays on-going photogrammetric surveys which will produce the updated cartography of the region in the form of a database with geo-referenced and topologically structured data (the Italian definition is Database Topografico, and the acronym is DBT). Usually, the towns’ technical departments have cartographic data available in digital format, which means that at least a part of their digital information archives are geographically referenced. However, this does not imply that all the data are already organized as a DB. In general, when newly surveyed data have to be integrated with already existing digital archives containing spatial and thematic information, the challenge is twofold: (a) to structure the existing data archives according to the rules of relational DB design (in the case that it is not already so), in order to obtain a model which univocally organizes and describes the information content of the GIS (thus allowing also for data interoperability); (b) to incorporate the new updated cartographic data (DBT) in the “old” database, without compromising the newly created structure. Both aspects can be studied and solved in the frame of conceptual modeling, which represents the basis for structuring large sets of data enabling to manage a variety of applications for a wide spread of potential users. In this paper, a conceptual model is presented for a relational database for a GIS application to be the main tool supporting everyday work of a Consortium of Local Municipalities in Regione Lombardia. Solutions are presented for both problems described above. After logical modeling, the system was implemented and tested at a prototype level, showing that several data sets (many of them with spatial reference) could be structured in a unique database, producing analysis and elaborations both in an automatic and efficient way.

Australasian Journal of Information Systems, 1998

We present a systematic evaluation of different modeling techniques for the design of Geographic Information Systems as we experienced them through theoretical research and real world applications. A set of exemplary problems for spatial systems on which the suitability of models can be tested is discussed. We analyse the use of a specific database design methodology including the phases of conceptual, logical and physical modeling. By employing, at each phase, representative models of classical and object-oriented approaches we assess their efficiency in spatial data handling. At the conceptual phase, we show how the Entity-Relationship, EFO and OMT models deal with the geographic needs; at the logical phase we argue why the relational model is good to serve as a basis to accommodate these requirements, but not good enough as a stand alone solution.

2008

A summary of the development of a database for a geographic information system. The commonly described disadvantages of the relational model (fixed length fields and an excess of tables) were overcome in a variety of ways, allowing the retention of the advantages of the model. The Binary Data Model (BDM) was used to define the system specifications. A software tool was developed to convert the BDM specification into tables in a relational model and into an object oriented interface to the relational database. A small, dedicated development team followed a strict development cycle, resulting in all major milestones being met. One of the main themes in this paper is the handling of complex (spatial) data that does not obviously suit the relational model.

The GeoJournal Library, 2007

An important research trend in databases is to handle different types of uncertainty at both conceptual and logical levels for various non-traditional applications that may involve imprecision and uncertainty that have been difficult to integrate cohesively in simple database models. In this study we describe how to conceptually model complex and uncertain information at the conceptual level (by utilizing the ExIFO 2 model) for Geographic Information System (GIS) applications. We also give the mapping algorithm that transforms the conceptual schema of GIS applications into the logical database structures by utilizing the fuzzy object-oriented database (FOOD) model at the logical level. The types of uncertainty that we mainly focus in this paper are fuzzy, null, and incomplete information related to objects and their properties, classes, and relationships among objects and classes of GIS applications.

Frontiers of geographic information technology, 2006

architecture, right: integrated architecture (courtesy of Vijlbrief and Oosterom van 1992). Figure 8.1. Evolving architectures of GIS. Left: dual architecture; middle: layered

2005

The Commission on Spatial Data Standards of the International Cartographic Association (ICA) is working on defining spatial models and technical characteristics of a Spatial Data Infrastructure (SDI). To date, this work has been restricted to the Enterprise and Information Viewpoints from the ISO Open Distributed Processing standard. The Commission has developed models for these two viewpoints. The models describe how these two different parts of an SDI fit together in the viewpoints in question. The models cannot be seen as a final result, but more as a small step towards a model that defines the previously mentioned overall model of the SDI and its technical characteristics. During the model development process, the role of the different actors in an SDI have also been identified in Use Case diagrams of an SDI. The model is developed using the Unified Modelling Language (UML).

2010

In the last 20 years, several conceptual data models specific for Geographic Information Systems (GIS) have been proposed. However, so far there isn’t a consensus model, which has generated several problems for the GIS area, such as the lack of interoperability among CASE tools that give support to these models. A UML profile, called GeoProfile, was proposed to standardize the task of geographical data modeling. This article shows the integration of GeoProfile with the international standards of ISO 19100 series, which are addressed to geographical information. This integration is presented through the different abstraction levels of the approach Model Driven Architecture (MDA).

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FAZ, 2024

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