Most of the European Rivers are defeated by simultaneously growing anthropogenic use and ecological claims while they are also complex, sensitive ecosystems with multiple interactions. Resulting questions require a description of the involved streams. The base of a qualified opinion about these ecosystems must be a multitude of various hydrological, biological, physical and chemical data. River basin management is the intellectual foundation to respond to these challenges. The interest in this topic raised accordantly and led in Europa to the EU-Water-Directive (EU-WFD), which was empowered in December 2000 and requires a thinking in river basin borders more than in borders of states or countries. Regarding these tasks, GIS based prognosis and management systems are considered to receive a raising meaning, mainly related to the support of decisions in spatial management. Subsequently we can observe a growing integration of GIS and Databases, often embodied in Spatial Databases, which contribute to solutions refering to the increasing claims on river basin management. This work is engaged in the search for possibilities to access the inner structure of river systems, the so called topological network, to transfer them into logical networks, reflected by hierarchical attributes, using the abilities of GIS to automate such processes. These attributes should be useable from both sides: the GIS and the (Relational) Database System. Because of the requirement to use these attributes with standard SQL (Structured Query Language) it should be possible to implement SQL-queries on such logical networks in both: more general available databases and high-end-products. Unfortunately we don't always find digital geometrical data in an appropriate state for these tasks. Digitalisation of stream networks and their processing enable different sources of errors to invade the desired results embodied in unclosed segment ends, wrong directions, intersections, overlays and many more. Therefore, the beginning of the work was marked by the search for possibilities to automatically correct such networks. Positive effects are, of course, the amout of time saved by using these tools and the opportunities to standardize not only the quality of the geometric data but also the use of their underlying hierarchical order. These advantages could contribute to a border-crossing data exchange between European countries and support synergetic effects. |