Providing Geological Knowledge by GIS

Communication in geology is characterized by very many expressions, used in texts and lectures. Among these, nonverbal terms are much more important than in other sciences. Informations rarely reflect pure facts, rather they are expressions and results of a complex process of knowledge formation. In a geologic map for example, the structure of symbols illustrates the process of knowledge transfer, which is a reflection of knowledge formation, that is building a model by chains of conclusions and hypotheses. Modern communication technologies imply new possibilities and, as a consequence, new standards of knowledge transfer. GIS development still focusses the digitalized analogous map. This is a map which represents the latest result of the complex regional geologic model, summarized and abstracted in polygons. Facts and their variations as well as their alternative interpretations still are discussed in explanatory notes. But, if we reflect knowledge representation in maps and texts, we will have to change our habit of communication. The classic demand, that the "ancient" geologic map is to display observations in such a way that users can find their data easily and understand their significance (BENDER 1981), obtains a new weight. The knowledge behind the polygons, that is hypotheses and inferences, ought not to be regarded self-evident any more. In this context, our project can be seen as pure research. Starting with the theory of geo-science and with how scientists draw their conclusions, we have analyzed problems of geologic knowledge formation and knowledge transfer. Our object of investigation and realization was the geologic map of Nordrhein-Westfalen 1:25.000, sheet 4617 Brilon (STEUERWALD 1992, 1996). Two user groups can be distinguished. The first group is "looking forward", making prognoses mostly deductively, in order to solve real world problems (KÜBLER 2000). The second group is "looking backward" at the modelling process combined with the geologic map. In this article we will adopt the view of a backward looking geologist. We will look at the history of a map, the development of the underlying map model as related to the region under concern and its geologic history: How does such a model work? Which components does it have? What theories are employed or construed by the map author?