Study On Construction Of Three-dimensional Surface Model For Urban Roads

Since urban roads are the space ties connecting different functional districts and the main carriers of the spatial information flow in cities,the 3D road model is the key and indispensable part of Digital City and 3DCM.Generally,3D road model is constituted of road surface model(the main part)and subsidiary structure models.Urban roads are great different from intercity highways in the spatial structure and spatial information,therefore,the existing research results can’t be directly applied to construct 3D models of urban roads in terms of model sophistication and overall amount of data.For this reason,this thesis starts from the data base of the 3D urban road model,designed key technologies of the construction for 3D urban road surface model through analyzing the spatial characteristics of urban roads,and achieves the construction of surface paths in the aspect of all kinds of urban roads.Finally,an experimental urban zone is selected to verify the method in the thesis.Based on the above research ideas,this thesis mainly completes the following work:1 Analyze the 3D modeling data of urban roads.Based on the analysis of the information sources and main effects of 3D city modeling,the thesis emphasizes the space elements and data organization of digital line maps,studies the method of extraction spatial information of urban roads from the digital line maps,and briefly analyzes the spatial information.2 Study spatial characteristics of the urban roads and designed key technologies of modeling 3D road surface accordingly.Through analyzing the spatial characteristics of urban roads based on the spatial information data,the thesis designs the methods to integration of the 3D urban road surface model,and to construction 3D spatial patches of road surface.The integration of the 3D urban road surface model focuses on the relations of the spatial organization and the simplification of spatial topology.While the construction of the 3D spatial patches applies the methods of space division and local fitting,the methods of slope smooth and characteristic generalization,and the spatial form of road surface to construct,optimize,and adjust the roads along their main directions respectively in order to achieve the construction road surface patches according to spatial characteristics of urban roads.3 Design the detailed modeling strategies for different kinds of road surface.Using key technologies mentioned above and integrating the morphological characteristics of various spatial entities of urban roads,this thesis designs the modeling strategies of 3D spatial suface paths for these spatial entities of the urban roads including motor lanes,non-motor lanes,sidewalks and sidewalk slope.4 Choose a typical study area for the validation of the proposed methods.The experimental results show that the proposed methods in this paper can realize the construction of 3D models for different kinds of road surface in a better way of spatial accuracy and spatial form,which basically meet the needs of practical applications.In summary,based on existing researches and spatial characteristics of urban roads,the thesis proposes methods to construct the 3D road surface model in an urban environment.The experiment proves that the result of proposed 3D surface model for different types of urban roads is basically correct and has a certain value in practical applications.