Dealing with Multiple Accuracy Levels in Spatial Databases with Continuous Update

Alberto Belussi 1, Maria Antonia Brovelli 2, Mauro Negri 3, Giuseppe Pelagatti 3 and Fernando Sansò 2
1 Dipartimento di Informatica, Università degli studi di Verona
Strada Le Grazie, 15, 37100 Verona, Italy
Fax: + 0039 045 802 7xxx
alberto.belussi@univr.it
2 Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie, Rilevamento, 
Politecnico di Milano – Polo Regionale di Como
Via Valleggio 11, 22100 Como, Italy
Fax: + 0039 031 3327519
maria.brovelli@polimi.it, fernando.sanso@polimi.it
3 Dipartimento di Elettronica e Informazione, Politecnico di Milano 
Politecnico di Milano
Via Ponzio, 34/5, 20100 Milano, Italy
Fax: + 004 555 874 414

Abstract
It is widely recognized that most Spatial Databases should be continuously updated, and that this goal can be reached only through the integration with the information systems that they serve, since most of the information required to perform the updates should be obtained from the administrative processes of the institutions which control the territory. However, since the different update processes collect spatial data  with different accuracy, one of the main problems in dealing with continuous update  is the requirement of managing data having different levels of accuracy also at instance level. Moreover, in this scenario a correct update process should address the two following goals: i) to use the updates having a high level of accuracy in order to increase the overall accuracy level of the spatial database; ii) to maintain the correct representation of all the qualitative spatial properties of the information (i.e. topological properties, like containment, adjacency, etc, but also other geometric properties, like parallelism, shape types, etc…). It can be shown that sometimes there is a conflict between the above two goals which is difficult to overcome. The main contribution of the paper is to propose an approach to perform an update that  overcomes the above conflict and achieves both the goals stated above. In particular, one of the possible techniques in data handling that could reasonably cope with such an endeavour is to use a Bayesian approach to the updating concept. Some elementary examples will clarify the benefits of this approach.

Keywords: Bayesian approach, spatial databases, multiple accuracy levels, continuous update

In: Caetano, M. and Painho, M. (eds). Proceedings of the 7th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences, 5 – 7 July 2006, Lisboa, Instituto Geográfico Português

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