Using Vector and Raster-Based Techniques in Categorical Map Generalization

Categorical data are a frequent data type in GIS and thematic cartography. Therefore, comprehensive methodologies for the generalization of categorical data in both the vector and the raster model are urgently needed. After the presentation of a general framework and recommended workflow, generic cartographic constraints governing the generalization of categorical data are specified. In the next step, these constraints will be translated into tools for assessing the need and the quality of generalization solutions as well as tools for achieving the necessary generalization transformations. These tools are usually associated with a particular data model. Typical and frequent generalization problems are used to study how the constraints can be best translated and parameterized in a particular data model, and how particular solutions perform in comparison to others. The last component of this paper relates to the conversion of data between the vector and the raster model and vice versa and explores how such operations can be usefully integrated into a generalization strategy.