It is an established fact that more than half of the world’s population currently resides in urban areas, and this trend is expected to reach 70% by 2050. These areas, although covering only a small portion of the earth’s surface, have highly significant consequences since they are responsible for 80% of total energy consumption and 75% of carbon emissions. This has resulted in an increase in land consumption due to growing urbanisation, which has seen metropolitan centres expand at the expense of rural and peripheral areas. An exemplification of this phenomenon is provided by the metropolitan city of Naples. The utilisation of three-dimensional urban models for the purpose of monitoring urban sprawl is supported by this scientific evidence. In the three-dimensional reconstruction of urban features, such as building heights, Airborne Light Detection and Ranging (LiDAR) elevation data, along with other available vectors, are crucial. The potential applications of such models are manifold, including but not limited to urban planning, design, and microclimate assessment. Among the technologies related to Remote Sensing, the Global Navigation Satellite System (GNSS) is fundamental for acquiring spatial data. However, in urban areas, due to the high density of buildings and their elevation, output data is tied to the position of the GNSS receiver to plan robust analyses. The objective of this research work is to georeference the 3D vertical building structure of the metropolitan city of Naples. To this end, a spatial analysis is first carried out to assess how the height of the buildings affects the line of sight between the Global Navigation Satellite System (GNSS) and the ground station in order to facilitate the acquisition of data in Real Time. Subsequently, the Digital Surface Model (DSM) and the Digital Terrain Model (DTM) of the metropolitan city of Naples are combined to construct the 3D model of the buildings. Finally, in support of the city’s Digital Twin (DTC), the cloud model is switched to facilitate all future operations related to the Real Time description of complex urban physical assets. The restitution of the 3D model of the city supports remote sensing technologies, including GNSS positioning. This in turn facilitates real-time description of the spatio-temporal dynamism of the clusters from which the DTC is composed. This, in turn, supports urban sustainability, security and environmental resilience.
Keywords: 3D City Urban Models 1; Building Height 2; Digital Twin City (DTC) 3; Geographic Information Systems (GIS) 4; Satellite Visibility Analysis 5.