BIM And GIS Data Conversion Method For Transportation Infrastructure

Transportation is an important social service industry that provides different forms of transportation services for people to travel and trade goods,and also has a strategic position in social and economic activities.Transportation infrastructure is an important carrier of transportation and an important part of the realization of intelligent transportation.The digitalization of transportation infrastructure,as the base of transportation digitalization,is the most basic step to build an intelligent transportation system and plays a very important supporting role for the realization of intelligent transportation.Modern information technology provides technical support for the construction of digital transportation infrastructure.Through the integrated application of various technologies can play the unique advantages of different technologies,of which the integrated application of building information modeling(BIM)and geographic information system(GIS)is a hot issue.Technology integration can realize the data fusion of different technologies through data conversion.However,since BIM and GIS come from different fields,there are big differences in data structure,description methods,geometric information and semantic expressions between them,which lead to the problems of low efficiency,information loss,semantic errors and application difficulties in the process of mutual conversion.The geometric and location information of the model is the most basic information and plays a crucial role in visualization and analysis.However,in the conversion process of BIM and GIS format,there may be problems such as part of the structure of the 3D model cannot be displayed and the model size does not match.The research in this paper selects the common IFC format file of BIM model and the Shapefile format file of GIS model shape representation for the integration study of BIM and GIS.The IFC file of the BIM model is parsed and reconstructed to form a Shapefile file from the perspective of geometric and spatial relationships.Specific studies include: firstly,the BIM model is constructed in the BIM software;then the model is analyzed in terms of spatial level,position relationship,geometry and formation method by analyzing the formation method of the model in the IFC file layer by layer;then the placement position information and geometric structure information of different levels of the model are extracted,and then the geometric representation information of the extruded entities(including closed profile,circular profile,rectangular profile and other profiles,extruded direction,extruded depth and other attributes)and boundary representation entities are analyzed,and the geometric representation information is converted according to the position placement information using the conversion algorithm to obtain the absolute position information of each structural part of the model;finally,a 3D model composed of different multipatches was generated in the Shapefile file based on this and loaded in the GIS software.The results show that the method proposed in this study can realize fast conversion from IFC format data to Shapefile format data,with accurate geometry information,controllability and smaller model capacity,which provides a reference method for the study of BIM and GIS data integration.The research contribution of this paper is to propose a BIM-GIS data conversion method based on spatial location information and geometric information,which achieves good conversion efficiency and display effect.