A mapping method of integrating multi-scale river thematic maps

Abstract. Small-scale maps are generally used in spatial analysis for fast calculation, but part of important features are missing due to its generalization level, which makes the analysis results less accurate. Therefore, it is necessary to improve feature completeness of smallscale maps. The goal of this paper is to put forward a mapping method of integrating the existing multi-scale river thematic maps. In order to achieve this goal, this paper proposed an algorithm for multi-scale line features matching by calculating the distance from node to polyline and an integrating algorithm by simplifying, shortening and merging the features from the original multi-scale thematic maps. The experimental results proved that the new map produced by the method proposed in this paper keeps the same scale as the original small-scale map and it is consistent with the original large-scale map in terms of feature completeness. The strategy proposed in this paper can be used to produce a new river thematic map concluding all the features that users need; moreover, the new map not only expresses features completely but also takes up less storage.