The Study On The Technology Of 3d Modeling And Visualization In Urban Pipeline

Along with the economic development and the improvement of the modernization of city, the geographic information system of 3D pipe has become a new hot spot for research and development. The data model of 3D pipe, the creation of spatial database and the method of data indexing is the basic of 3D pipe system, and the 3D visualization and spatial analysis are the technical problems that need to be resolved in 3DGIS development. With the supports of ministry of Science and Technology international cooperation project, this dissertation deeply studies the integrated network system for data storage, indexes and the arithmetic of 3D visualization. The main contents and innovations can be summarized as follows1,The design and implementation of general pipe spatial databases and spatial data engine.(1)Starting with the special characteristics of underground pipe,it studies on the data model,uses geodatabase model'idea for reference,designees the shape geometry storage structure of 3D pipe,initially forms a 3D spatial databases structure of comprehensive network data.(2)Design and implements the spatial data engine of 3D pipe,which makes use of database index table to speed up rate of real-time scheduling of a large amount of data integrated network data,achieves effective management of network data to establish a model data sets,and displays the 2D and 3D together in the data and visualization layer.2,The implementation of 3D visualization and spatial analysis functions of pipe, and the studies of key technology.(1)Multiple technologies are integrated together to realize 3D visualization of every feature, such as Com, GDAL open source library; It also proposes a method based on GPU to smooth the join,which improves the effect 3D visualization;(2)Import hash mapping, which is the technique about data storage and access in information system, into 3D visualization to carry out the efficient management of complex resources in 3D pipe system.(3)Multiple elimination algorithm are integrated together to ensure the real-time property for lots of 3D pipe rendering of the engine, which include the back-face elimination, the view frustum culling, and LOD arithmetic.(4)Space geometry analysis of mathematical is used to pick up every pipe feature by point, and then it come true the 3D display of exploding by graph theory and particle systems.3,The development of 3D pipe GIS borrowing the idea from MVC model design, which has been appling in practice. At last, a 3D pipe GIS (3DPipeGIS) is founded, with power function, sound effect and stable performance, which uses the pipe data of area of NanChang to be tested, and has a good effect.