Abstract
Abstract. With the development of digital city, digital applications are more and more widespread, while the urban buildings are more complex. Therefore, establishing an effective data model is the key to express urban building models accurately. In addition, the combination of 3D building model and remote sensing data become a trend to build digital city there are a large amount of data resulting in data redundancy. In order to solve the limitation of single modelling of constructive solid geometry (CSG), this paper presents a mixed modelling method based on SCSG-BR for urban buildings representation. On one hand, the improved CSG method, which is called as “Spatial CSG (SCSG)” representation method, is used to represent the exterior shape of urban buildings. On the other hand, the boundary representation (BR) method represents the topological relationship between geometric elements of urban building, in which the textures is considered as the attribute data of the wall and the roof of urban building. What's more, the method combined file database and relational database is used to manage the data of three-dimensional building model, which can decrease the complex processes in texture mapping. During the data processing, the least-squares algorithm with constraints is used to orthogonalize the building polygons and adjust the polygons topology to ensure the accuracy of the modelling data. Finally, this paper matches the urban building model with the corresponding orthophoto. This paper selects data of Denver, Colorado, USA to establish urban building realistic model. The results show that the SCSG-BR method can represent the topological relations of building more precisely. The organization and management of urban building model data reduce the redundancy of data and improve modelling speed. The combination of orthophoto and urban building model further strengthens the application in view analysis and spatial query, which enhance the scope of digital city applications.
Highlights
With the continuous development of digital city, the requirements of urban building modelling are getting higher and higher, and the complexity of building shapes leads to great difficulties in modelling complex urban buildings accurately
An improved constructive solid geometry (CSG) modelling method--voxel growth method, is proposed; and a hybrid modelling method based on CSG and boundary representation (BR) is proposed by WANG J S
In order to accurately establish complex urban building models with real texture images, a hybrid modelling method based on Spatial CSG (SCSG)-BR for complex urban buildings is proposed
Summary
With the continuous development of digital city, the requirements of urban building modelling are getting higher and higher, and the complexity of building shapes leads to great difficulties in modelling complex urban buildings accurately. The combination of the building model with real texture and the remote sensing image meets the requirements of the development of the digital city and makes more sense to the three-dimensional modelling. The city tree was treated as the data structure for urban 3D model. In terms of data integration, Zhou G was presented a method, which integrates image knowledge and LiDAR point cloud data for urban digital terrain model (DTM) and digital building model (DBM) generation. In order to accurately establish complex urban building models with real texture images, a hybrid modelling method based on SCSG-BR for complex urban buildings is proposed. This paper combines the building model with real texture and the corresponding orthophoto to realize the modelling and operation of spatial information query and analysis in digital city
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