# Integration of BIM and GIS for the Digitization of the Built Environment
## 3 Methodology
### Open-Source Methodology
MMQGIS 2.99 is a plug-in that provides a wide range of tools for analyzing, managing and manipulating geographic data, with a particular focus on vector data [66]. This tool is appreciated for its flexibility and ability to extend the basic functionality of QGIS, making it an essential element for those who regularly work with spatial data. Key features of MMQGIS include tools for geocoding and reverse geocoding, allowing addresses to be converted to geographic coordinates and vice versa, using external services such as OpenStreetMap or Google Maps. It also offers a wide range of options for managing and manipulating vector data, such as merging, splitting, dissolving layers or creating buffers, regular grids and random points. The plug-in supports advanced operations such as merging tables, splitting layers based on attribute values and calculating new fields. Other useful tools include the ability to manage labels, create thematic maps and export data in a variety of formats including CSV, KML and GPX for easy use on other platforms such as Google Earth or GPS devices. Installation follows the same procedure as above. QuickMapServices 3.22 is a plug-in that simplifies access to base maps and map web services, making it an essential tool for anyone working on GIS projects [67]. Its intuitive interface allows you to quickly integrate online maps into your projects without complex configuration. It offers pre-configured base maps from popular providers such as OpenStreetMap, Google Maps, Bing Maps and Esri, as well as thematic maps such as satellite imagery, topographic surveys and street maps. It also supports online map services (WMS, WMTS, TMS), allowing custom maps to be added and managed via URL. The plug-in has a search function to quickly find available maps and offers the ability to cache maps for faster access, which is useful in contexts with limited connectivity. The installation process is identical to that described above. The support of these plug-ins enables the creation of a database of georeferenced elements comprising multiple layers, which are associated with the typology of the asset, as well as the generation of a two-dimensional graphic representation, which may represent a building, infrastructure or terrain (Figure 3). The contribution of these innovative functions makes it possible to optimize BIM-GIS integration, providing support both at the level of geographic maps and at the level of simplifying the search for different assets on the territory. Each asset is classified according to the aforementioned typologies, and is placed in the reference layer, which is distinguished by color. An MMQGIS script can be employed to automatically insert the available documentation of an asset into the table of its characteristics. Consequently, once the assets under discussion have been georeferenced, it is possible to enter all the necessary information with reference to the polygon. The set of all documents entered into the software constitutes a GIS database, subdivided into layers, which can be consulted and exported in different formats (Figure 4). The database enables the management of assets at the territorial level, thereby permitting the analysis of the territory for urban planning or restoration projects. On the other hand, it is also necessary to have a BIM model of a building or infrastructure in order to operate at a more detailed level. The digital model represents the informational contribution related to the characteristics of the building work. The creation of a model of an existing building can be achieved in two ways:  
1. A digital survey of a work can be conducted through the use of drones or laser scanners [68]. 2. The creation of a model of an existing building can also be initiated from available documentation, even if it is not in digital format [69]. It is well established that the fidelity of a model derived from a point cloud is superior to that of a recalculation of design drawings. [PERSON] et al.