Integrated 3D Modeling Of Underground Pipeline Networks

The stable operation of the underground pipeline network ensures the circulation of urban basic resources and the people's daily life.It is especially important to understand and control the construction status and management status of the underground pipeline network.Because underground pipeline networks has a wide range of distribution and buried underground,the exploration and maintenance of pipeline networks is not convenient.Traditional 2D pipeline network management can't express the intricate spatial relationship between pipeline networks.Being a main development trend of GIS,people found that 3D GIS can reflect the geometric features and distribution characteristics of spatial objects better than 2D GIS,and it can present complex geospatial objects to users in a simple and clear way.Applying 3D GIS to pipeline network management can solve the problems of exploration and spatial analysis of underground pipeline network,and greatly improve the intuitiveness and operability of pipeline network management system.3D modeling of underground pipeline networks has gradually become a hot issue in pipeline network management research.At present,there are some problems in most 3D model construction schemes of pipeline network,such as imprecision of model,incomplete semantics and inability to update dynamically,and lack of spatial analysis ability,which makes it difficult to truly facilitate the unification and management of pipeline network information.In view of the existing problems,this paper summarizes the geometric characteristics of the pipeline networks,combines the requirements and existing difficulties in the actual management of the pipe network,establish the geometric data model and semantic data model of the pipeline network.The finished 3D model will contain the appearance,geometric features and semantic information of the pipeline networks.The disordered basic data and information in the pipeline networks were reorganized according to the presentation hierarchy and topological constraints.The paper proposes to calculate the rotation angle of pipe fittings and other visualization parameters according to the fitting interface classification,which lays a foundation for the quick matching of pipe fittings and pipelines.SuperMap SDX+ spatial data engine is adopted to store the basic data of pipeline networks,and the integration of 2D and 3D data is realized from the data storage level.Comprehensively comparing the advantages and disadvantages of face-based data structure and volume-based data structure,this paper combines structural solid geometry(CSG)and boundary representation(B-Rep)mixed data structure to construct 3D model of underground pipeline networks.Modeling the pipe fittings and pipelines with different data structures,so that the finished model can meet the requirements of flight browsing,query,statistics,etc.in the pipeline network management system.Establish a network model library to reduce the time cost of future pipeline networks modeling.The 3D visualization of the upper floor corresponding to the underground pipe network makes the underground pipeline networks and the ground layer form a complete 3D scene,which is conducive to the positioning and identification of the pipeline networks.A series of operations such as model cache and scene optimization are carried out on the whole scene to speed up the loading speed of 3D scene.Finally,the pipeline networks model is applied in the pipeline network management system to realize various operations such as query,pipe burst analysis and net distance calculation,proving that the finished pipeline networks 3D model in the study can indeed meet the needs of accurate expression,dynamic update and comprehensive analysis in pipe network management.