Digital techniques have been widely used in cartography since the 70s, and a rapid development in computer technology has taken place in the last decade. In generalization, however, which is one of the major topics of cartography, there is still no adequate solution in a scientific and/or practical sense. On the other hand, these new technologies have led to a rapid development in the field of data capture in cartography and related disciplines. In developed countries in particular, the era of data capture is almost complete. National Mapping Agencies have built large data bases that include mostly large-scale data, i.e., in base map resolution. For applications in smaller scales, existing large-scale data should be used through digital generalization, to avoid redundancies in data capture and to ensure consistency between different data sets that represent the same geographic area.
Although generalization is a complex and subjective process, some important solutions to problems of generalization have been developed. Prominent studies, which are recognized worldwide, have been undertaken at the Institute for Cartography of Hanover University, especially in the generalization of large-scale data. Based on these studies, the CHANGE software product was developed, which is capable of processing building and road objects.
The main subject of this thesis is to apply and to expand the approach of Hanover to Turkish map data. For the case study digital large-scale maps produced by the mapping service of the Municipality of Metropolitan Istanbul were selected. These maps include almost all possible settlement structures that can be seen in the city. Not only the possibility of applying the Hanover solution is investigated, but also the expansion of this approach. This latter aim is realized in the study through the development of substitute programs. A further innovation is the integration of CHANGE, which has no interactive component, with an interactive CAD-GIS system, namely AutoCAD MAP. Here, a universal data exchange standard, DXF, is used, which makes it possible to integrate CHANGE, the kernel system, with most of the CAD-GIS software. Consideration of the quality of generalization and GIS applications after generalization, the topological and semantic consistency and adequate graphic quality of the digital data before and after generalization are important issues. In order to meet these requirements, substituting programs developed for this study expand the approach proposed here. Moreover, a new approach, namely building generalization in separate logical regions, is realized.
Finally, CHANGE, AutoCAD MAP and the substitute programs are components of an integrated system that can be used by National Mapping Agencies and similar institutions. Consideration of the case study of this thesis shows the evident applicability of this system.