Comparative Analysis of the Semantic Conditions of LoD3 3D Building Model Based on Aerial Photography and Terrestrial Photogrammetry

3D modeling of buildings is an important method in mapping and modeling the built environment. In this study, we analyzed the differences between the semantic state of actual buildings and 3D models of LoD3 buildings generated using aerial and terrestrial photogrammetric methods. We also evaluated the accuracy of the visual representation as well as the suitability of the building geometry and texture. Our method involves collecting aerial and terrestrial photographic data and processing it using SFM (structure from motion) technology. The photogrammetric data was then processed using image matching algorithms and 3D reconstruction techniques to generate 3D models of LoD3 buildings. The actual semantic state of the building was identified through field surveys and reference data collection. The 3D building model was successfully modeled from 1201 photos and 19 ground control points. The results of the evaluation of the geometry accuracy test, dimensions and semantic completeness of the 3D model, the use of aerial photographs and terrestrial photogrammetry in LoD3 3D modeling are assessed from the results of the automatic 3D modeling process using SfM (Structure from Motion) technology that produces 3D building models in Level of Detail (LoD) 3 with Root Mean Square Error values <0.5 meters and has semantic completeness of the building in accordance with the original object based on the City Geography Markup Language (CityGML) standard. The facade formed from the modeling almost follows the original model such as doors, windows, hallways, etc

Automated texture mapping CityJSON 3D city models from oblique and nadir aerial imagery

The incorporation of detailed textures in 3D city models is crucial for enhancing their realism, as it adds depth and authenticity to the visual representation, thereby closely mimicking the surfaces and materials found in actual urban environments. Existing 3D city models can be enriched with energy-related roof and façade details, such as the material type (such as windows, green façades, bricks) and sunlight reflectance which can be derived from texture information. However, a common limitation of these models is their lack of very high resolution textures, which which reduces their realism and detail. Manually mapping textures onto each surface of a building is an exceptionally time-consuming and labor-intensive process, making it unfeasible for large-scale applications involving thousands of buildings. Therefore, an automated method is essential for texture mapping of 3D city models from aerial imagery. In this paper, we present CityJSON texture mapper – a python-based software tool for automated texture mapping of CityJSON-based 3D city models from oblique and nadir aerial imagery. Experimental results demonstrate the effectiveness of our approach in generating high-quality textured 3D city models, showcasing the potential for broader applications in geospatial analysis and decision-making. This research contributes to the ongoing efforts in enhancing the realism and usability of CityJSON-based 3D city models by enhancing them with their real textures from oblique aerial imagery. Texture mapped model can be explored at https://bit.ly/textured3dbag

ASSESSING TERRESTRIAL MMS 3D DATA FOR OUTDOOR MULTI-SCALE MODELLING

Mobile Mapping Systems (MMS) have recently benefited from the development of many fusion-based technologies with countless systems development based on cars, drones, trolley, wearable or portable mapping system. The scale of applicating range from the urban to the architectural scale. Recent solution are also based on visual or Lidar SLAM (Simultaneous Localization and Mapping), which substantially takes advantage of environmental features and techniques of continuous co-registration of the clouds, also in case of absence on GNSS positioning measurement. FARO Technology has recently developed the Swift, a fusion-based hybrid solution that integrates the sensors for 3D mapping in a trolley system configuration and recently, an external camera Panocam Theta Z1 is equipping the system enabling the possibility to associate radiometry to the acquired data. The working principle is the exploitation of a system of static and mobile configuration, using the so-called “anchor scans” co-registration as an hybrid intermediate solution between a typical static scan and a profilometers-based MMS point cloud. The co-registered clouds therefore yield a trajectory mode such as SLAM but benefit from the comparable range and density characteristics, according to user-customized settings, of static scans, with a duration of a few seconds per scan and a few minutes overall. In the present research the Swift System is tested in two different context and the assessment are conducted aimed at satisfying both the urban and the architectural scale instances in the direction of improving further evaluations

URBAN DESIGN STRATEGIES FOR THE UPCYCLING OF URBAN INFRASTRUCTURE RESIDUAL POCKETS: 3D CITY MODELLING FROM OPEN DATA AND LOW-COST RAPID MAPPING TOOLS

This paper deals with the 3D City Modelling specific procedure developed as a tool to support strategies for urban regeneration, within the framework of the B-ROAD research project.The B-ROAD research project, whose acronym stands for Below the Road, is developing urban design strategies for upcycling urban infrastructure residual pockets.The B-ROAD’s methodology is conceived as research by design as it is carried out by creating pilot scenarios, disclosing the latent and still unexpressed potential of these wasted areas and displaying their potential transformations, to turn them into precious resources for the contemporary city.The 3D City Modelling of the study area has proved to be essential and strategic yet often complex and critical as most of the spatial and architectural features of B-ROAD spaces, as well as their potential, cannot be detected nor represented through the traditional means of representation of urbanised land, as aerial survey-based representations, or GIS. Likewise, traditional, or even cutting-edge, survey techniques that can be used to acquire missing data are often costly and time-consuming, thus making it hardly impossible to achieve the purpose of extensive and deep knowledge of such a vast area. Thus, 3D City Modelling aimed at examining spaces and providing a final representation of pilot scenarios has been a crucial stage requiring a specific in-depth study.</p

HBIM MODELLING FOR AN HISTORICAL URBAN CENTRE

The research in the geospatial data structuring and formats interoperability direction is the crucial task for creating a 3D Geodatabase at the urban scale. Both geometric and semantic data structuring should be considered, mainly regarding the interoperability of objects and formats generated outside the geographical space. Current reflections on 3D database generation, based on geospatial data, are mostly related to visualisation issues and context-related application. The purposes and scale of representation according to LoDs require some reflections, particularly for the transmission of semantic information. This contribution adopts and develops the integration of some tools to derive object-oriented modelling in the HBIM environment, both at the urban and architectural scale, from point clouds obtained by UAV (Unmanned Aerial Vehicle) photogrammetry. One of the paper’s objectives is retracing the analysis phases of the point clouds acquired by UAV photogrammetry technique and their suitability for multiscale modelling. Starting from UAV clouds, through the optimisation and segmentation, the proposed workflow tries to trigger the modelling of the objects according to the LODs, comparing the one coming from CityGML and the one in use in the BIM community. The experimentation proposed is focused on the case study of the city of Norcia, which like many other historic centres spread over the territory of central Italy, was deeply damaged by the 2016-17 earthquake

Urban design strategies for the upcycling of urban infrastructure residual pockets: 3D city modelling from open data and low-cost rapid mapping tools

This paper deals with the 3D City Modelling specific procedure developed as a tool to support strategies for urban regeneration, within the framework of the B-ROAD research project. The B-ROAD research project, whose acronym stands for Below the Road, is developing urban design strategies for upcycling urban infrastructure residual pockets. The B-ROAD’s methodology is conceived as research by design as it is carried out by creating pilot scenarios, disclosing the latent and still unexpressed potential of these wasted areas and displaying their potential transformations, to turn them into precious resources for the contemporary city. The 3D City Modelling of the study area has proved to be essential and strategic yet often complex and critical as most of the spatial and architectural features of B-ROAD spaces, as well as their potential, cannot be detected nor represented through the traditional means of representation of urbanised land, as aerial survey-based representations, or GIS. Likewise, traditional, or even cutting-edge, survey techniques that can be used to acquire missing data are often costly and time-consuming, thus making it hardly impossible to achieve the purpose of extensive and deep knowledge of such a vast area. Thus, 3D City Modelling aimed at examining spaces and providing a final representation of pilot scenarios has been a crucial stage requiring a specific in-depth study