Study On Cartographic Generalization Of Relief Based On TIN And RGD

The cartographic generalization of relief is one of the most important parts of the cartographic generalization. The automatic cartographic generalization of relief is one of the most important and complicated parts of the cartographic generalization which divided by feature type, it could provide the control information for the cartographic generalization of other type of feature. The contour and Regular Grid Digital Elevation Model(RGD) are two kinds of important model of relief, this paper studied the theory and algorithm of the cartographic generalization of relief, designed the method of cartographic generalization of relief based on Triangulated Irregular Network (TIN) and the method of cartographic generalization of relief based on RGD and carried out the generalization experiment with 1:250000 topographic map data, analyzed the generalization effect of the several kinds of algorithms for different geomorphic type, and put forward the improve method for farther study. The main works are as the following:1. This paper designed the method of cartographic generalization of relief based on TIN for the geomorphological data which in the form of contour, first, construct the TIN model by contour, and then implement the generalization by simplify the TIN model. In order to insure the precision of the simplified TIN model, we added the control information of the terrain into the TIN model, such as triangulation point, elevation point and orographic character line. This paper studied the interrelated algorithms of the method of cartographic generalization of relief based on TIN which include the examine algorithm of graphical data of contour, the algorithm of extracting orographic character line, the algorithm of constructing and update of triangulation, the algorithm of simplification of TIN model and the algorithm of generate contour based on TIN model.2. This paper designed the method of cartographic generalization of relief based on RGD for the geomorphological data which in the form of RGD, this paper study the algorithm of wavelet analysis and the algorithm of filter analysis which based on wavelet analysis, and implement the generalization by simplify the RGD model with these algorithm, and then generate contour datafrom RGD model.3. Analysis of the effect of the algorithms. This paper implement the generalization throughthe two kinds of methods of cartographic generalization for relief with the real 1:250000 relief map data. Based on the two kinds of methods of cartographic generalization for relief, this paper carry out cartographic generalization of relief with different type of geomorphic data, and analyzed the generalization effect of the several kinds of algorithms for different geomorphic type with different parameter.4. Improvement of the algorithms. From the analyses of this paper, we know that there are still some disadvantages on the efficiency of each algorithms and generalization effect of each algorithms, this paper proposes some improve methods for further study.