With the increasing role that unmanned aerial systems (UAS) are playing in data collection for environmental studies, two key challenges relate to harmonizing and providing standardized guidance for data collection, and also establishing protocols that are applicable across a broad range of environments and conditions. In this context, a network of scientists are cooperating within the framework of the Harmonious Project to develop and promote harmonized mapping strategies and disseminate operational guidance to ensure best practice for data collection and interpretation. The culmination of these efforts is summarized in the present manuscript. Through this synthesis study, we identify the many interdependencies of each step in the collection and processing chain, and outline approaches to formalize and ensure a successful workflow and product development. Given the number of environmental conditions, constraints, and variables that could possibly be explored from UAS platforms, it is impractical to provide protocols that can be applied universally under all scenarios. However, it is possible to collate and systematically order the fragmented knowledge on UAS collection and analysis to identify the best practices that can best ensure the streamlined and rigorous development of scientific products.

Cultural heritage conservation demands interdisciplinary and complex documentation and analysis while facing increasing pressure to adopt sustainable and productive practices. This paper bridges these gaps by proposing a methodology and a set of requirements for Building Information Modeling (BIM) models aligned with European directives for sustainability and productivity in the Architecture, Engineering, and Construction (AEC) sector. Leveraging 3D scanning and intelligent models, we establish information needs specific to conservation, encompassing material properties, historical data, and decay analysis. Interoperability, compatibility with advanced analytical tools, and open-source formats are emphasized for seamless data integration and accessibility. We further introduce two use cases for BIM-enabled heritage conservation, illustrating the application of our proposed methodology in real-world scenarios. These cases exemplify how BIM models cater to the specific needs of cultural heritage sites, from their initial condition assessment to ongoing preservation efforts. Through these examples, we demonstrate the adaptability of BIM technology in capturing and managing the complex information associated with heritage conservation, including structural details, material characteristics, and historical significance. Our work highlights the potential of BIM to revolutionize heritage conservation practices, offering a digital backbone for documentation, analysis, and management that aligns with sustainability and productivity goals.

The digitization of Cultural Heritage is an important activity for the protection, management, and conservation of structures of particular historical and architectural interest. In this context, the use of low-cost sensors, especially in the photogrammetric field, represents a major research challenge. In this paper, the use of cameras capable of capturing a 360° scene with a single image was assessed. By using spherical photogrammetry and the algorithm based on the structure from motion and multi-view stereo, it is possible to reconstruct the geometry (point cloud) of an object or structure. In particular, for this experiment, the Ricoh theta SC2 camera was used. The analysis was conducted on two sites: one in the laboratory and another directly in the field for the digitization of a large structure (Colonada in Buziaș, Romania). In the case study of the laboratory, several tests were carried out to identify the best strategy for reconstructing the 3D model of the observed environment. In this environment, the approach that provided the best result in terms of both detail and dimensional accuracy was subsequently applied to the case study of Colonada in Buziaș. In this latter case study, a comparison of the point cloud generated by this low-cost sensor and one performed by a high-performance Terrestrial Laser Scanner (TLS), showed a difference of 15 centimeters for 80% of the points. In addition, the 3D point cloud obtained from 360° images is rather noisy and unable to construct complex geometries with small dimensions. However, the photogrammetric dataset can be used for the reconstruction of a virtual tour for the documentation and dissemination of Cultural Heritage.

Small unmanned aerial systems (UASs) equipped with an optical camera are a cost-effective strategy for topographic surveys. These low-cost UASs can provide useful information for three-dimensional (3D) reconstruction even if they are equipped with a low-quality navigation system. To ensure the production of high-quality topographic models, careful consideration of the flight mode and proper distribution of ground control points are required. To this end, a commercial UAS was adopted to monitor a small earthen dam using different combinations of flight configurations and by adopting a variable number of ground control points (GCPs). The results highlight that optimization of both the choice and combination of flight plans can reduce the relative error of the 3D model to within two meters without the need to include GCPs. However, the use of GCPs greatly improved the quality of the topographic survey, reducing error to the order of a few centimeters. The combined use of images extracted from two flights, one with a camera mounted at nadir and the second with a 20° angle, was found to be beneficial for increasing the overall accuracy of the 3D model and especially the vertical precision.

The manuscript intends to describe different methodologies for the acquisition, data processing, and identification of strategies aimed at improving the quality of 3D point cloud production using latest-generation sensors in the field of cultural heritage surveying. The point clouds taken into consideration were acquired by passive and active sensors on the Buziaș site, an important historical and architectural structure in Romania. In particular, a spherical camera (Ricoh Theta Z1) was used in order to obtain a video; subsequently, starting from the video, more datasets were extracted and processed in a photogrammetric software based on Structure from Motion and Multi View Stereo algorithms. In addition, a Simultaneous Localization And Mapping (SLAM) sensor (ZEB Revo RT) was used in order to generate a point cloud. The different point clouds produced were compared with the data obtained through a Terrestrial Laser Scanner (TLS) survey. Statistical analyses were carried out to check and validate the results obtained from the comparison between the different techniques and data acquisition methods. The statistical analysis showed that the model obtained with the GeoSLAM was metrically more accurate and detailed than the point cloud generated by the videogrammetric processing highlighted in this study. The paper also analyzes the performance of the three different sensors used, including parameters such as acquisition (timing and ease of use), processing (timing and ease of use), results (accuracy, resolution, and chromatic quality), and costs (instrumental and operator).

The study explores the impact of floods, phenomena amplified by climate change and human activities, on the natural and anthropogenic environment, focusing on the analysis of a section of the Cigher River in the Crișul Alb basin in western Romania. The research aims to identify areas vulnerable to flooding under different discharge scenarios, assess the impact on agricultural lands, and propose a reproducible methodology based on the integration of GIS technologies, hydraulic modeling in HEC-RAS, and the use of LiDAR data. The methodology includes hydrological analysis, processing of the Digital Elevation Model (DEM), delineation of geometries, hydraulic simulation for four discharge scenarios (S1–S4), and evaluation of the flood impact on agricultural and non-agricultural lands. Evaluated parameters, such as water velocity and flow section areas, highlighted an increased flood risk under maximum discharge conditions. The results show that scenario S4, with a discharge of 60 m³/s, causes extensive flooding, affecting 871 hectares of land with various uses. The conclusions emphasize the importance of using modern technologies for risk management, protecting vulnerable areas, and reducing economic and ecological losses. The proposed methodology is also applicable to other river basins, representing a useful model for developing sustainable strategies for flood prevention and management.