# Integration of BIM and GIS for the Digitization of the Built Environment
## 3 Methodology
### Open-Source Methodology
The provision of an IFC-compliant interface for export and import enables software application providers to guarantee interoperability with a multitude of other tools. [PERSON] et al. [61], in their discussion of BIM-GIS integration for the purpose of enhancing urban management, highlight the role of standards such as the IFC and City Geography Markup Language (CityGML) [62]. However, this study identifies a significant challenge in the transformation of these standards, namely the discrepancy between them in terms of geometry and semantics. In order to address this issue, an ontology-based-rule mapping approach has been developed, which enables the transformation from IFC to CityGML through coordinate system conversion. [PERSON] et al. [63] address the complexity of the problem of georeferencing BIM models and the need for a comprehensive solution by focusing on the open BIM data format of IFC. Although the IFC already encompasses some of the concepts, an extension of the IFC schema is proposed to address any inadequacies. The proposal consists of two new entities: one supporting geographic reference systems (GIS) and the other allowing a rigid transformation of BIM geometries. The tools used for the integration process between BIM and GIS in OSE are illustrated below (Figure 1). For the GIS environment, QGIS 3.20.3 software was chosen (Figure 2), which permits the identification of various real-world assets such as land, roads, or other features [64]. QGIS is a software designed for the management, analysis, and visualization of spatial data. QGIS's flexibility, versatility and extensive toolset make it an invaluable resource for scientific research and project implementation across a range of fields, including urban planning, environmental management, precision agriculture and natural resource monitoring. The software is compatible with a multitude of spatial data formats, including vector formats (such as shapefiles, GeoJSON and GPKG) and raster formats (such as GeoTIFF and satellite images), thereby ensuring broad interoperability with other platforms and data sources. The software enables sophisticated spatial analysis operations, including layer overlay, buffer calculation, proximity analysis and raster modelling, rendering it particularly well-suited to multidisciplinary studies and complex geospatial applications. This is done using information derived from cadastral data and other documentation. The initial stage of the process requires the configuration of certain software settings, including the loading of the base map to serve as a reference for the assets. A new connection can be created through the \"Data Source Manager\" function using the \"XYZ Tile\" option. This procedure enables the loading of Google Satellite and cadastral maps. Subsequently, the location and identification of real estate and land can be undertaken. To facilitate this process, three plug-ins have been identified:  
Figure 1: OS methodology chart. Figure 2: QGIS interface, layer and geospatial map. OSM Place Search 1.4.5 is a QGIS plug-in designed to simplify the search for places using OpenStreetMap (OSM) data [65]. It allows you to quickly locate and center your map view on a place, address or point of interest. Key features of the plug-in include the ability to search for cities, addresses, monuments or other geographical locations using the OpenStreetMap database. It integrates seamlessly into the QGIS interface and presents itself as an easy-to-use search bar or dialogue box. Once the desired location is selected, the map is automatically centered on the search result, making navigation fast and intuitive. The plug-in also supports place names in different languages, depending on the information available on OSM. Its intuitive interface makes it suitable for both beginners and advanced QGIS users. The installation involves opening QGIS, go to Plugins > Manage and Install Plugins, search for OSM Place Search in the search bar, select the plugin and click Install. Once installed, the plug-in will be available in the QGIS toolbar.