Research On A Three-dimensional Building Data Model Considering Indoor Reachable Space

Nowadays,the urbanization process is accelerating continuously,and indoor space has become the main place for people to work and live.Cross-domain applications such as "smart cities",indoor and outdoor integrated navigation,emergency rescue,disaster prevention and mitigation have increasingly higher requirements for spatial data quality.Therefore,providing three-dimensional path planning services has become an urgent problem.Because traditional path planning is mainly based on two-dimensional map data,it is difficult to meet the above needs because of the lack of path planning in true three-dimensional space.Therefore,this paper intends to take the indoor three-dimensional structure of the building and the three-dimensional reachable space enclosed by it as the research object,and according to the existing three-dimensional data model rich in rich semantic information,a three-dimensional spatial data model of the building that takes into account the integrated modeling of indoor visible geometric components and three-dimensional reachable space is proposed.This model can support functions such as data conversion,data storage,spatial segmentation,spatial analysis,three-dimensional path planning,and provide better technical and method support for the above-mentioned multifaceted applications.The main research contents and results of this article are as follows:(1)Propose the conceptual model,geometric structure and physical storage model of the building spatial data model considering indoor three-dimensional reachable spaceThe existing building spatial data models which are rich in semantic are studied,and the characteristics of models such as BIM model,City GML model,Indoor GML model are compared and analyzed.According to the characteristics of the above models,which can not directly satisfy the indoor 3D reachable space modeling and true 3D navigation,the conceptual model,geometric structure and database storage model of the building spatial data model that takes into account indoor 3D reachable space are designed to provide a basis for the application of the following data model.(2)Realize indoor three-dimensional space division based on octreeThe indoor three-dimensional space segmentation method was studied,and a three-dimensional space data model using Morton encoding was established which combined octree and Z sorting.It not only expresses the solid parts of the building,but also models and divides the three-dimensional reachable and navigable space enclosed by the solid.(3)Construction of indoor 3D connected relation and its application in indoor 3D navigationBased on the designed model,a 2.5D indoor network connectivity diagram that meets pedestrians is generated.Extract the octree of the indoor three-dimensional reachable space segmentation result of the navigation class,and determine the connectivity between the navigation classes from the level of semantic topology,and generated a true three-dimensional navigation connectivity map that can be used for unmanned aerial vehicles’ true three-dimensional indoor navigation and other applications.Combined with the above research content,this paper takes the City GML model converted from BIM data as the data source,converts it into the three-dimensional spatial data model of the building proposed in this paper,and carried out three-dimensional split experiment,indoor navigation path extraction algorithm experiment and so on.The verification results show that the proposed model can combine the solid components of the indoor space with the three-dimensional reachable space enclosed by it,and combine the geometric and semantic representation of indoor space with the application of the model,expand the operability of the model,and provide the possibility for further in-depth research and application.