Generalization is needed to describe relevant information on an appropriate level of detail. However, the harmony
between different generalized geographic features are always difficult to be ensured even if the data sources come from
the same topographic maps or geographic databases, as the generalization is carried out separately in the context of
computer assisted cartography. This paper introduces a new approach for the harmonic generalization of terrain and
water system based on the integrated geographic feature retrieval using 3D Douglas-Peucker algorithm. The advantage
of the research is two folded: firstly, it focuses on the geographic nature of water system and terrain; secondly, the 3D
Douglas-Peucker algorithm is developed to make this generalization of the two kinds of features possible. The spatial
representation of water system in vector data and that of the terrain in DEMs are unitized into one set of general
character points. Then the 3D Douglas-Peucker algorithm is performed for the features retrieval. After that, the result is
returned to generate the abstracted terrain and the simplified water system. In this way, the harmonic registration
between the generalized terrain and the generalized water system can be ensured. The preliminary experiments show that
this harmonic generalization is a promising way both in cartography and GIS.
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