Feature as a Component of Hydrological Information Conceptual Model
The analysis presented here was conducted as part of preliminary work within the confines of the 9 T12B 025 18 research project, entitled structural and functional basic model for object systems of geospatial information in hydrogeology, based upon OpenGIS specification, CORBA and UML language. Its objective is to determine the types and subtypes for data aggregates that should be included in the data model. Assumption of object - orientation, based upon the paradigm derived fromUML(Unified Modelling Language) for this model, results in the necessity of representation of non-object features (in accordance with the meaning adapted by geomatics) as objects corresponding with them, understood as programming entities (in accordance with the meaning provided in the definition of object, given above). In this sense, base types and subtypes of features are represented by base classes and derived classes of objects. As a consequence, a feature is treated as an instance of a feature type, and an object is an instance of a class.
Design and construction of hydrogeological information systems is now a necessity. For proper functioning of these systems, it is necessary to create them in accordance with widely accepted international standards and specifications (Michalak, 2001b). Therefore, the base model developed here will be based upon current work of the OpenGIS Consortium and adapted for normalisation purposes by the Technical Commitee ISO/TC211 (Kuhn, 1997). The norms worked out by ISO/TC 211 will be adapted as European norms, and, as a consequence, as has been announced by the Polish Normalisation Commitee, they will also become Polish norms (Chowañska - Szwoch, 2000). One of the basic methodological problems is application of the XML metalanguage (eXtensible Markup Language) to hydrogeological information (Michalak, 2000a). However, these works and the related norms pertain only to the geospatial aspect, and the remaining, non-geospatial aspects of the base model, which are typical of hydrogeology, require application of solutions worked out and agreed upon by the hydrogeological community (Michalak, 1997a). From the point of view of computer science, this community is understood as the hydrogeological information community in the sense specified in the OpenGIS Abstract Specification (The OpenGIS…, 1999).
Reference :
Janusz Michalak, Faculty of Geology, Warsaw University
Tags: component of hydrological, CORBA, european norms, geospatial aspect, OpenGIS, technical Commitee, typical of hydrogeology, UML language