Macrotidal beach monitoring (Belgium) using hypertemporal terrestrial lidar

Macrotidal Beach Monitoring (Belgium) using Hypertemporal Terrestrial Lidar Greet DERUYTER, Lars De SLOOVER, Jeffrey VERBEURGT, Alain DE WULF, Belgium and Sander VOS, the NetherlandsKey words: Continuous Terrestrial Laser Scanning, Coastal Monitoring, Beach Mapping, North SeaSUMMARY In order to protect the Belgian coast, knowledge on natural sand dynamics is essential. Monitoring sand dynamics is commonly done through sediment budget analysis, which relies on determining the volumes of sediment added or removed from the coastal system. These volumetrics require precise and accurate 3D data of the terrain on different time stamps. Earlier research states the potential of permanent long-range terrestrial laser scanning for continuous monitoring of coastal dynamics. For this paper, this methodology wasimplemented at an ultradissipative macrotidal North Sea beach in Mariakerke (Ostend, Belgium). A Riegl VZ-2000 LiDAR, mounted on a 42 m high building, scanned the intertidal and dry beach in a test zone of ca. 200 m wide on an hourly basis over a time period of one year.It appeared that the laser scanner could notbe assumed to have a fixed zenith for each hourly scan. The scanner compensator measured a variable deviation of the Z-axis of more than 3.00 mrad. This resultedin a deviation of ca. 900 mm near the low water line. A robust calibration procedure was developed to correct the deviations of the Z-axis. In this paper, we start by presenting the first results achieved with the current methodology. Next, we analyze the results from a 10-day measurement campaignand highlight the tide-dominated beach morphology

Macrotidal beach monitoring (Belgium) using hypertemporal terrestrial lidar

Macrotidal Beach Monitoring (Belgium) using Hypertemporal Terrestrial Lidar Greet DERUYTER, Lars De SLOOVER, Jeffrey VERBEURGT, Alain DE WULF, Belgium and Sander VOS, the NetherlandsKey words: Continuous Terrestrial Laser Scanning, Coastal Monitoring, Beach Mapping, North SeaSUMMARY In order to protect the Belgian coast, knowledge on natural sand dynamics is essential. Monitoring sand dynamics is commonly done through sediment budget analysis, which relies on determining the volumes of sediment added or removed from the coastal system. These volumetrics require precise and accurate 3D data of the terrain on different time stamps. Earlier research states the potential of permanent long-range terrestrial laser scanning for continuous monitoring of coastal dynamics. For this paper, this methodology wasimplemented at an ultradissipative macrotidal North Sea beach in Mariakerke (Ostend, Belgium). A Riegl VZ-2000 LiDAR, mounted on a 42 m high building, scanned the intertidal and dry beach in a test zone of ca. 200 m wide on an hourly basis over a time period of one year.It appeared that the laser scanner could notbe assumed to have a fixed zenith for each hourly scan. The scanner compensator measured a variable deviation of the Z-axis of more than 3.00 mrad. This resultedin a deviation of ca. 900 mm near the low water line. A robust calibration procedure was developed to correct the deviations of the Z-axis. In this paper, we start by presenting the first results achieved with the current methodology. Next, we analyze the results from a 10-day measurement campaignand highlight the tide-dominated beach morphology

Renewed e-learning oriented IHO Cat. B Hydrography Program (2020-) in Belgium

A study onhydrographic education in Belgium carried out a few years ago,pointed out a shortage in hydrographic training. Before the introduction of the new "Postgraduate in Hydrography", most hydrographic surveyors in Belgium work in one of the main Europeandredging companies where they received additional specific hydrographic surveying training.Therefore, in 2013, a 1-year English spoken curriculum degree of "Postgraduate in Hydrography" in Belgium was accredited by the IHO (International Hydrographic Organization). Then, in 2019, a renewed curriculum, including extensive e-learning facilities, was established.The program (Cat-B) is a cooperation between the Geography Department of Ghent University and the Institute for Hydrography of the Antwerp Maritime Academy, which is the hosting institute.The aim is to combine the compulsory theoretical courses with on-the-job training provided by partners in the industry to ensure maximum competences. All courses are lectured in English, and can be taken up over several years to facilitate part-time work. These procedures allow for a qualitative and professional, yet accessible program.The theoretical courses are taught on two different campuses, the campus of the Antwerp Maritime Academy (HZS) and a campus of Ghent University (UGent) based on the available expertise and infrastructure, thus ensuring the quality. As travel time between both cities is relatively fast (ca. 45 min. travel time by public or private transport) together with the boundary condition that both locations are never used on the same day, this presents no problems to the students. The navigation related topics are taught at the Maritime Academy while the geodesy/data management/geology and ICT related topics are provided by the Geography, Geology and Informatics Departments at Ghent University

Assessment of handheld mobile terrestrial laser scanning for estimating tree parameters

Sustainable forest management heavily relies on the accurate estimation of tree parameters. Among others, the diameter at breast height (DBH) is important for extracting the volume and mass of an individual tree. For systematically estimating the volume of entire plots, airborne laser scanning (ALS) data are used. The estimation model is frequently calibrated using manual DBH measurements or static terrestrial laser scans (STLS) of sample plots. Although reliable, this method is time-consuming, which greatly hampers its use. Here, a handheld mobile terrestrial laser scanning (HMTLS) was demonstrated to be a useful alternative technique to precisely and efficiently calculate DBH. Different data acquisition techniques were applied at a sample plot, then the resulting parameters were comparatively analysed. The calculated DBH values were comparable to the manual measurements for HMTLS, STLS, and ALS data sets. Given the comparability of the extracted parameters, with a reduced point density of HTMLS compared to STLS data, and the reasonable increase of performance, with a reduction of acquisition time with a factor of 5 compared to conventional STLS techniques and a factor of 3 compared to manual measurements, HMTLS is considered a useful alternative technique

A review of the internet of floods : near real-time detection of a flood event and its impact

Worldwide, flood events frequently have a dramatic impact on urban societies. Time is key during a flood event in order to evacuate vulnerable people at risk, minimize the socio-economic, ecologic and cultural impact of the event and restore a society from this hazard as quickly as possible. Therefore, detecting a flood in near real-time and assessing the risks relating to these flood events on the fly is of great importance. Therefore, there is a need to search for the optimal way to collect data in order to detect floods in real time. Internet of Things (IoT) is the ideal method to bring together data of sensing equipment or identifying tools with networking and processing capabilities, allow them to communicate with one another and with other devices and services over the Internet to accomplish the detection of floods in near real-time. The main objective of this paper is to report on the current state of research on the IoT in the domain of flood detection. Current trends in IoT are identified, and academic literature is examined. The integration of IoT would greatly enhance disaster management and, therefore, will be of greater importance into the future

Measuring surface moisture on a sandy beach based on corrected intensity data of a mobile terrestrial LiDAR

Surface moisture plays a key role in limiting the aeolian transport on sandy beaches. However, the existing measurement techniques cannot adequately characterize the spatial and temporal distribution of the beach surface moisture. In this study, a mobile terrestrial LiDAR (MTL) is demonstrated as a promising method to detect the beach surface moisture using a phase-based Z&F/Leica HDS6100 laser scanner mounted on an all-terrain vehicle. Firstly, two sets of indoor calibration experiments were conducted so as to comprehensively investigate the effect of distance, incidence angle and sand moisture contents on the backscattered intensity by means of sand samples with an average grain diameter of 0.12 mm. A moisture estimation model was developed which eliminated the effects of the incidence angle and distance (it only relates to the target surface reflectance). The experimental results reveal both the distance and incidence angle influencing the backscattered intensity of the sand samples. The standard error of the moisture model amounts to 2.0% moisture, which is considerably lower than the results of the photographic method. Moreover, a field measurement was conducted using the MTL system on a sandy beach in Belgium. The accuracy and robustness of the beach surface moisture derived from the MTL data was evaluated. The results show that the MTL is a highly suitable technique to accurately and robustly measure the surface moisture variations on a sandy beach with an ultra-high spatial resolution (centimeter-level) in a short time span (12 x 200 m per minute)

3D modelling Yar City : application of UAVs for archaeological research

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