Study And Practice On Adaptability Of 3D Terrain Modeling Algorithm

3D terrain modeling is one of the key technologies in virtual scene simulation. Building proper digital elevation models for all kinds of terrains is the key to provide precise geographic data. To build model accurately, we put forward the concept of adaptation of 3D modeling algorithm. Its signification is to select corresponding algorithm according to the characteristic of the terrain when we are building DEM for different relief of different scales, to meet all kinds of needs. In order to seek the adaptation of 3D terrain modeling algorithm in this paper, we study characteristics of various terrains and some common algorithms to start with and improve those algorithms. Some directive conclusions have been drawn by experiments, which may provide valuable references to 3D terrain modeling in the future. The following contents are included.1. In this paper, we summarize the theories and methods in current researches on algorithms and precision evaluation of 3D terrain modeling. In addition, we analyze the shortage and weakness of the above and put forward an adaptation modeling rule for the algorithm, according to the characteristic of the terrain.2. In order to solve the modeling problem in flat regions, the traditional weighted mean method is improved, and a distance-weighted algorithm is put forward, based on finite searching areas, to construct DEM, which improves the modeling precision and efficiency. By experiments, the adaptation rules of 3D modeling algorithm have been concluded.3. In order to solve the modeling problem of DEM in large regions we adopt two combination methods, moving surface fitting method and bilinear interpolation method, either combined with weighted mean method, which improves the modeling precision. By experiments and analysis on contour line data for typical relief of different scales, an adaptation rule for the combination algorithm is put forward, which may provide valuable reference for precise modeling in the future.4. Through programming we implement the method of generating regular grid DEM, based on contour dilation, which is offered by Hind Taud. And by experiments with contour line data of different scales and different relief types, we find out some existent problems and bring out the modeling method of selecting corresponding interpolating contour lines for different relief types.5. Combined with task demands, we designed and finished a system for modeling and evaluation with the object-orient method. It can do some help to support theory research technically.The research in this paper provides not only some theories and methods for 3D terrain adaptation modeling, but also scientific reference to similar research and quality control for the modeling in the future. It is of significant value in theory and practice.