Research On Triangle Mesh And Transmission Of Complex 3D Terrain

The accuracy and quality of spatial data has been gradually improved with the development of the fields such as geological, GIS and remote sensing, and it also brings popularization on digital earth, DTM and other technologies. On the one hand, network transmission became a kind of essential way because of people’s increasing demand for spatial data while all areas of spatial data application is becoming widespread, and the data sharing mode is becoming more flexible. On the other hand, a sharp raise in the amount of spatial data on field geological collection and remote sensing also put forward a higher requirement on the efficiency of data operation and application.At the same time, with the expansion of CG and 3D VR. people’s requirement in terms of visualization is no longer limited in two-dimensional space. The demand of the three-dimensional data is also extended to GIS field. So visualization and network transmission of the three-dimensional spatial data have become important research contents. At present, there are many kinds of three-dimensional data modeling methods aiming at different using types. While the progressive transmission method of three-dimensional data has become widely recognized in the network transmission study, but due to the impact of network bandwidth, the three-dimensional data transmission is still unable to meet a flexible effect.To achieve three-dimensional application research of complex terrain, we took the whole operation process of the complex terrain as the main line in this paper from collecting discrete points, model construction, to its progressive transmission process insists of model simplification and reconstruction. In the former process, we come up with an improved method based on triangulation growth method of Delaunay triangulation which could achieve triangle meshing of the terrain, and the terrain data with constraint could be determined by adding a further test and identifier, which can improve topological accuracy. This paper proposes a local network progressive transmission scheme based on user demand in view of the three-dimensional terrain, which can avoid unnecessary detail data out of the screen delivering to the user’s local-refinement in selected area. This method can improve the transmission efficiency and refine the traditional progressive transmission process that based on global simplification and reconstruction operation.During the research process, we design programs based on Visual C++ and other related technology as the experiments to verify the validity of the algorithm and the scheme, which also provide reference for further research and application.