Indoor Routing by building a three-dimensional route network based on integration of BIM and GIS

With the development of complex urban infrastructure such as high-rise buildings, the importance of geospatial information in the interior of buildings becomes more apparent. Routing is one of the most basic processes related to geospatial information that existence of a precise and complete network of the desired environment is necessary for its efficiency. In most cases, a data set from the target network is required before performing any analysis on a route network; Having such data outside the building, such as Google Map and OSM data, as well as accessing it is much easier than inside the building. Access to such information requires geometric information and in some cases accurate semantic information of the building. In this regard, building information modeling technology (BIM), by providing useful information about buildings can help to build a route network in its interior. On the other hand, in order to complete the routing process, in addition to the route network, efficient tools for analysis on the route network are needed, which are not available in BIM. In this regard, Spatial Information Systems (GIS) have an ability to perform the required analysis in the routing process. Therefore, it seems that by combining BIM and GIS, the ground can be provided for better management of the routing process inside the building. In this research, the combination of BIM and GIS has been done with the aim of building an indoor route network using FME Reader software. In this research, the campus of the Faculty of Engineering, University of Tehran has been considered as the study building. In order to prepare a three-dimensional model of these floors, Revit Architecture 2017 software has been used. First, the two-dimensional map related to the plan of these classes is entered into the software environment and then the three-dimensional process is implemented in accordance with the necessary standards. After extracting the required data in the BIM model, this data has become the standard format in GIS. In order to eliminate the errors resulting from the conversion of data format from BIM to GIS, such as overshoot and undershoot errors, concepts and topological analysis in GIS have been used. Finally, the two proposed methods Mesh and TIN have been used to create the route network. The Mesh method uses regular grading of the region to create the route network, while the TIN method uses the Delaunay triangulation concepts to construct the route network. In the Mesh method, the number of points involved in routing is very high. High number of points increases the accuracy of routing, but processing these points in order to find the optimal path requires high hardware. The TIN method uses triangulation to network the environment, and therefore, due to the low number of points involved in the path network, information processing in order to find the best path requires less hardware power. Also in this study, the stairs were connected to each other as a straight line, which reduces the accuracy of routing. Routing can be used in technologies such as in-house positioning. The results of the research show the efficiency of the information in BIM models as well as the proposed methods in constructing the route network in the routing process.