An Approach For Quality Evaluation In Polygon Map Generalization

Map generalization is one of the most challenging technologies in the field of cartography and GIS. Different methods for map generalization have been developed. However, there are only a few publications that discuss the automatic quality assessment of generalized maps. In this paper we present a new approach for the quality assessment of generalized polygons. The researches in this dissert are summarized as follows:1. The map generalized operation are systematically stated, the influence of generalized operation for map spatial information are analyzed and constraints of map generalization are summarized and classified.2. In order to assess and control the quality of the generalization, this paper presents an approach for evaluation of quality in map generalization from the point of view of geometric similarity. Quantitative indicators are developed to measure three elements about geometric similarity, including shape similarity, location similarity and area similarity.3. This paper presents an approach for evaluation of quality in map generalization from the semantic change. Four basic elements are first put forward, which correspond to different aspects of semantic quality, including semantic accuracy, semantic consistency, semantic completeness and semantic similarity.4. In order to study geospatial information change, this paper introduce information theory for measure map geospatial information, including geometric information entropy, thematic information entropy, topological information entropy and thematic topological information entropy.A forest thematic map is used as a practical example to illustrate the feasibility and correctness of the proposed measures.Finally, the paper summarizes the findings, and some issues are highlighted for further investigations.