Study Of City 3D Modeling And Sharing Based On CityGML

With China's economic development, urbanization is rapidly accelerating. According to the year of 2007"China Urban Development Report"data, China's urbanization level has reached 45%. It already has nearly 600 million urban population and more than six hundred cities, and is still increasing at a rate of 1%. This is the urban dynamic monitoring and resource management unprecedented challenged. Digital City is also rapid development, to address these urgent needs. An important part of the digital city construction is establishment a large-scale urban scenes digital three-dimensional modal. At the large-scale urban scenes digital three-dimensional modal, we can display a variety of simulation and realistic city scene. Because the existing three-dimensional models stored in different file formats, cannot be effectively shared. There is the phenomenon of waste of resources. In addition, the traditional three-dimensional models contains only geometric information, not has the semantic and topological information. CityGML is a common information model for the representation of 3D urban objects. It defines the classes and relations for the most relevant topographic objects in cities and regional models with respect to their geometrical, topological, semantical and appearance properties. CityGML launched in 2008, it's practical application in foreign country not so many, mainly still in research and small-scale practical applications. The research in home is fewer, and mainly focused on the introduction of CityGML standards, and there are a few examples. The research on specific areas is relatively small, also has not propose a specific method on how to transform three-dimensional model from existing model to CityGML.This paper analyzes the status of domestic and international research, summed up the content of the study at home and abroad. Points out and summarized the current research problems, and how to solve the problem. Based on the study of CityGML characteristics, describes the use of related software, noted that the current software problems, create a simple example, gives the relevant code and browse views. Propose a third-party software to convert the existing models to CityGML models, and show a few examples related to the conversion process. The results show that to archive the excepted desired effect, for the subsequent three-dimensional model from the existing standard model of the conversion to the CityGML provides a reference method.This paper will have a few points:Through analyzes the status of domestic and international research, collate and summarized the content of the study at home and abroad. Points out and summarized the current research problems, and how to solve the problem.Research the open data model features of CityGML. CityGML development objective is to archive a common definition of three-dimensional city models entities, attributes and relationships. Through the research of CityGML's characteristics, we can understand the role of in three-dimensional modeling of city model.Summary the current generation methods of three-dimensional model and shortcomings, and compared the CityGML city three-dimensional objects common information model, describes the use of related software, noted that the current software problems, create a simple example, gives the relevant code and browse views.Summary the current generation methods of CityGML model. And compare and analysis these methods.Through FME to establish the process of convert three-dimensional model to CityGML data model, and browse the conversion results in CityGML software.