Aerial Laser and Photogrammetric Scanning for Flood Damage Assessment

11. Aug 2023

In light of the recent floods that have affected Slovenia, our company has conducted aerial laser and photogrammetric scanning of the majority of the affected areas across the country. Utilizing this technology, we have captured spatial data that will enable a quicker and more accurate assessment of the damage, as well as the establishment of foundational data for the rehabilitation of affected regions. We are actively collaborating with various stakeholders regarding data creation, access, and distribution, and the initial products will soon be available for use. Our company is committed to rapidly distributing this data to a wide range of users, thus the interim products will be released for non-commercial use through a link in the shortest possible time. Currently, we are in discussions with governmental bodies and other stakeholders regarding the final technical products.

Starting on Monday, August 7th, we commenced aerial scanning of the flooded areas along the Mura River and in the Poljanska Valley (central Slovenia). Additionally, on Tuesday, August 8th, 2023, we captured imagery of the Savinja, Mislinja, and Meža areas. This collective effort spans an impressive 1,700 km2. In order to ensure broad usability of the acquired data, we are collaborating with a diverse set of stakeholders including planners, municipalities, and the Water Directorate, with the goal of defining common objectives and optimizing the timing of aerial scanning.

Preliminary data collected during overflights of the affected regions indicate that for a more precise damage assessment, as well as for purposes of planning and reconstruction, it will be necessary to await the settling of watercourses and conduct another aerial scanning at a higher resolution. In the current conditions, stagnant waters have hindered the accurate determination of the extent of the damage caused by the calamity. Furthermore, there are still earth movements occurring in landslide-prone areas.

As a result, the current data will primarily serve to determine the extent of water flooding, rapidly identify significant critical events, and assess the interim situation. Much work has been undertaken to clear debris and remove material, but these actions are not yet visible in the imagery.

Versatile Utilization of Captured Spatial Data

From the imagery captured by RGB and NIR cameras with resolutions ranging from 5 to 10 cm, we will generate classical RGB orthophotos and composite orthophoto products featuring near-infrared spectrums for improved identification of waterlogged areas and inundations. Laser data (10-20 points/m2) will facilitate the creation of a digital terrain model, which will allow us to ascertain alterations in riverbeds, areas prone to landslides, and comparable terrain changes. Furthermore, juxtaposing this data with prior terrain configurations (for example, by leveraging LiDAR data from 2013) will contribute to a comprehensive understanding of alterations in surface morphology.

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