# A Unified Database Solution to Process BIM and GIS Data
## 5 Conclusions  
This article described research attempting to find an effective, practical, and useful method to integrate BIM and GIS data environments. After a detailed analysis of the various publications and the available BIM software, a new method of BIM and GIS data integration was proposed that used an integrated spatial database, which consisted of three different schemas (in terms of both the structure and the separate places in the database). However, it is not an integrated database in the full meaning of the term based on a uniform conceptual model but, rather, a solution based on the process of on-the-fly integration of data collected in several harmonized application schemes. The research included experimental works, as well as preparation of the solution prototype.  
Using a database as storage for IFC data allows GIS systems to use current BIM data without having to import IFC files into their formats/models, which opens up completely new functional possibilities. The proposed integrated database of BIM/GIS spatial data makes it possible to store GIS and BIM data, enabling the use of the same data by both types of systems simultaneously and in a consistent manner. This allows BIM systems to obtain simultaneous access to BIM and GIS data, which may be needed in, for example, the process of analyzing a building and its immediate surroundings. At the same time, GIS can obtain up-to-date building data necessary for spatial analyses, building management, or route mapping in navigation applications. In addition, users of BIM systems gain new technological solutions as follows:  
* Providing opportunities for group work offered by the management systems of relational databases with the possibility of using various BIM software while working on a single project.
* Providing standard mechanisms for controlling the access rights to the data offered by relational database management systems.
* Providing mechanisms for the transactional processing of the data offered by relational database management systems.
* Providing backup mechanisms offered by relational database management systems.  
The condition for implementing such a solution is to add a database access mechanism to the BIM tools. Such a mechanism could replace the existing BIM application functionality of working on its own data files in binary formats. This is probably one of the simplest solutions, because it requires only a technical modification without the need for integration into the conceptual model. In terms of GIS, virtually no significant modification is necessary, as long as the software supports the CityGML schema. Of course, there is nothing to prevent the proposed concept from being applied to data schemas alternative to CityGML. The proposed concept also makes it possible to create additional thematic schemas that allow access to the integrated BIM/GIS data stored in the BIGI-S in a way readable for other applications using these data, such as applications that support the process of property management.  
Conceptualization, M.W. and D.G.; methodology, M.W. and D.G.; investigation, M.W.; software, M.W.; data curation, M.W.; visualization, M.W.; writing--original draft preparation, M.W. and D.G.; writing--review and editing, D.G.; and supervision, D.G. All authors have read and agreed to the published version of the manuscript.  
This research work was financed from the funds for statutory research of the Warsaw University of Technology and grant number 504/03787/1060/42.000100.  
The authors express their gratitude to SWG Sweden for providing the data for the tests. Some tests were performed on the sample BIM model provided by the Institute for Automation and Applied Informatics (IAI)/Karlsruhe Institute of Technology (KIT).  
The authors declare no conflict of interest.