## 3 Interoperability Issues
### HBIM and GIS Integration: Semantic and Technical Interoperability
#### 3.3.1 HBIM-GIS Integration Using a Recent Function in a GIS Commercial Solution  
Starting from 2019, ArcGIS Pro allows us to directly insert the _.rvt_ file in a GIS context without intermediate transformations of data format. This procedure has been tested with the case study of the church and after the import of the model, the geo-referencing was observed. For this phase, many steps are still required. For the automatic geo-referencing of the 3D parametric model in the geographic information software, it is necessary to have the _.prj_ file containing the spatial projections, in this case UTM--WGS84 33N (EPSG:32633). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**IFC**} & \multicolumn{5}{c}{**CityGML**} \\ \cline{2-6}  & & **LoD 2** & **LoD 3** & **LoD 4** & \\ \hline \multirow{6}{*}{**IFcBuildingElem**} & \multirow{2}{*}{x} & BuildingInstallation & BuildingInstallation & exterior \\  & & & x & IntBuildingInstallation & interior \\ \cline{2-6}  & \multirow{2}{*}{IfcBeam} & \multirow{2}{*}{x} & BuildingInstallation & BuildingInstallation & exterior \\  & & & x & IntBuildingInstallation & interior \\ \cline{2-6}  & \multirow{2}{*}{IfcColumn} & \multirow{2}{*}{x} & BuildingInstallation & BuildingInstallation & exterior \\  & & & x & IntBuildingInstallation & interior \\ \cline{2-6}  & \multirow{2}{*}{IfcDoor} & \multirow{2}{*}{x} & Door & Door & \\ \cline{2-6}  & & & RoofSurface & RoofSurface & RoofSurface & exterior \\  & & & x & CeilingSurface & interior \\ \cline{2-6}  & \multirow{2}{*}{IfcSlab} & GroundSurface & GroundSurface & GroundSurface & exterior \\  & & x & x & FloorSurface & interior \\ \hline \multirow{2}{*}{IfcStair} & \multirow{2}{*}{x} & BuildingInstallation & BuildingInstallation & exterior \\  & & & x & IntBuildingInstallation & interior \\ \hline \multirow{2}{*}{IfcWall} & WallSurface & WallSurface & WallSurface & exterior \\  & & x & x & IntWallSurface & interior \\ \hline \multirow{2}{*}{IfcWindow} & \multirow{2}{*}{x} & Window & Window & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Correspondences between IFC and CityGML data objects. Finally, in the GIS environment it is possible to visualize the 3D model (Figure 10) and its contents, in addition to querying the geometries and to get information and characteristics of the building allowing different operations (maintenance phase, risk indicator, vulnerability parameters, management data...). Moreover, it is possible to view the church in its context adding the cartographic data from regional geoportal, surveys campaign and so on. Once the format compatibility issue for the insertion of the HBIM model in the GIS environment is overcome, the next problem is focused on semantic interoperability, analysing the correspondence of the attribute and data, in order to verify the loss of information and the possibility to integrate entities with new parameters (adding information) and the relations among objects. Different interoperability tests were performed in order to verify the completeness of the standard model and to integrate the information in a further phase of implementation. In particular, the verification of information belonging to IFC structure and not present in CityGML one and vice versa has been carried out. For the assessment concerning the IFC structure, the element \"Rood\" was chosen. During the investigation of the IFC and CityGML classifications (Section 3.1) some differences have been noticed. The IFC locates _IfcRoof_ in the category _IfcBuildingElement_, that contains the primary elements for the construction of a building, so its structural and spatial subdivision system. Moreover, each element is subdivided into sub-elements with a series of properties such as _Pset_Condition_ that contains _\"Assessment\"_ adopted into the San Lorenzo Chuch model to assign the parameters _ifcDate_, _IfcLabel_ and _IfcText_. Finally, _Pset_ManufacturerTypeInformation_ was identified that contains _\"ProductionYear\"_. All these parameters are absent in the CityGML conceptual reference model structure.