Research On Contour Reconstruction Algorithm And Dem Accuracy Evaluation

Nowadays, Digital Elevation Model (DEM) is playing an increasingly important part in many fields, such as surveying and mapping, resources and environment, disaster prevention and cure, national defense and other fields related to terrain analysis. A scientific measurement and accurate presentation for DEM data quality has become a popular problem that DEM producers and users highly care about. Combined with the research, the focus is on the optimization of the DEM-based contour reconstruction algorithm and the foundation of a DEM accuracy evaluation model based on this algorithm. The main contents include:1. Principles of several kinds of contour reconstruction algorithms based on TIN (Triangulated Irregular Network) and RGD (Regular Grid Digital Elevation Model) are summed up. The ideas and realization process of these different algorithms are compared and a detailed analysis on the accuracy and efficiency of these algorithms is also made.2. In this paper, RGD-based contour reconstruction algorithm is realized and optimized. Then several problems in main sections of the algorith, such as grid visiting principle, contour tracing process, two-meaning contour, direction consistency are dealt with in detail. Moreover, further optimization of the algorithm which is suitable for several special terrain types is given. Then, the reliability of the algorithm is analyzed by experimenting on different areas belonged to several typical geomorphic types.3. This paper evaluates DEM accuracy from two viewpoints, which are vision accuracy and measurement accuracy, by utilizing the contour reconstruction algorithm. Meanwhile, a new accuracy evaluation index, which is reconstructing offset error of important orographic character lines is put forward and DEM accuracy evaluation model based on the contour reconstruction algorithm is constructed.4. An approach to evaluate the accuracy of multi-scale DEM based on contour reconstruction algorithm is put forward. Finally, a fitting model of multi-scale DEM accuracy evaluation based on different interpolation methods by experiments is formed.Above all, this paper develops a new idea and method for DEM accuracy research and further improves the DEM accuracy evaluation system both academically and practically.