| Abstract |
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Database manager systems (DBMS) have been traditionally used for handling economic and alpha-numeric information, related to business, government, education, health, urbanism, etc. Making 3D geometry and topology and their related algorithms the raw material and subject of DBMS is rare. Attempts have been made in the specific field fo Geographic Information Systems (GIS). However, for historical and economical reasons 3D geometry and topology was appended on top of 2D entities. The mechanism found is usually the addition of 3D information in the form of attributes for, for example, vertical extrusions of 2D entities. The related algorithms usually handle the interrogations and constructs of GIS, even though some GIS systems contain3D geometry and Topology, in the sense of Geometric Modelling. This manuscript presents the usage of DBMS graph capabilities for approximation of hard core computational geometry algorithms. This rarely used approach has the advantage of avoiding degenerate situations, at the price of lower precision. Taping into the vast graph capabilities of DBMSs has the obvious advantage of large algorithm libraries, which in this case we apply to computational geometry. The lower geometric precision of graph-based DBMS algorithms do not hamper their application, in problems of dimensional reduction, mesh parameterization and segmentation, etc. This manuscript is also attractive in that it illustrates the articulation of freeware display systems (e.g. JavaViewTM) with DBMS for computational geometry applications. |
