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Advances in Remote Sensing in Coastal Geomorphology

A special issue of Remote Sensing (ISSN 2072-4292).

Deadline for manuscript submissions: closed (30 July 2022) | Viewed by 40266

Special Issue Editors


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Guest Editor
Department of Graphic Expression, Polytechnic School, University of Extremadura, 10003 Cáceres, Spain
Interests: geodesy; cartography; photogrammetry; cultural heritage; glacier movement; coastal regression
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Geology, Faculty of Geology, University of Oviedo, 33005 Oviedo, Spain
Interests: geology; estuaries; coastal and port management; dunes; beaches; coastal geomorphology; anthropocene
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Geography, Faculty of Geography and History, University of Santiago de Compostela, 15704 Santiago de Compostela, A Coruña, Spain
Interests: geomorphology; coastal geomorphology; rock coasts; beaches; dunes; late pleistocene; holocene
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The wave action on the coast is a cause of continual geomorphological changes. Although many coastal areas are sparsely populated clifftops, almost half the world’s population lives in coastal regions, some of which depend upon “sun and beach” tourism. Large storms have become increasingly common, leading to the phenomenon of coastal retreat. These carry a high risk of destruction, particularly of beaches and dunes close to populated areas.

There are now a great many methods of remote detection available to record this information, such as satellite images or aerial photogrammetry, as well as others closer to land, in which geodesic–topographic, on-land photogrammetry, UAV, lidar, and TLS techniques are used. Depending on the methodology used, precisions vary from metric to millimetric. Studies in newly emerging sectors are often linked to underwater dynamics, sedimentation, and morphology. There are other techniques applicable in the field of oceanography that facilitate data acquisition in underwater areas. These are mono- and multibeam echo sounders, acoustic doppler profilers, seismic reflection or sidescan sonar.

This Special Issue invites authors to submit scientific articles exploring or recording the evolution of both natural and inhabited areas of the shoreline through the use of remote sensors.

Dr. José Juan de Sanjosé Blasco
Dr. Germán Flor-Blanco
Dr. Ramón Blanco Chao
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Geomatics techniques
  • Coastal remote sensing
  • Storm impact
  • Coastal processes
  • Coastal geomorphology
  • Shoreline change
  • Coastal erosion
  • Sea level change
  • Coastal and ports management
  • Oceanography
  • Anthropocene

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Related Special Issue

Published Papers (11 papers)

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29 pages, 9642 KiB  
Article
Application of Geomatic Techniques for the Assessment of Anthropogenic Changes in the Urban Beaches of “La Magdalena” (Santander, Spain)
by Germán Flor, Manuel Sánchez-Fernández, Germán Flor-Blanco and José Juan de Sanjosé Blasco
Remote Sens. 2023, 15(1), 256; https://doi.org/10.3390/rs15010256 - 1 Jan 2023
Viewed by 1896
Abstract
Since the 1970s, dredging sands have been poured onto the embayed beaches of La Magdalena in the western mouth of the estuarine Bay of Santander (N Spain) in order to increase beach width. Up until the year 2000, the sands were systematically fed [...] Read more.
Since the 1970s, dredging sands have been poured onto the embayed beaches of La Magdalena in the western mouth of the estuarine Bay of Santander (N Spain) in order to increase beach width. Up until the year 2000, the sands were systematically fed by a trailing suction dredge, which was later replaced by truck sand transfers from the surplus sands of the western beach to the eastern ones and by mechanical redistribution to create artificial berms. A recent project aimed to solve sand losses after each storm by building two perpendicular breakwaters about 620 m apart. The eastern breakwater was built in the early summer of 2018, and wave storms in November 2018, February 2019, October 2020 and the last days of 2021 progressively dismantled the reconstructed upper beach areas and eroded other segments. The western breakwater, however, designed to retain the E–W sandy beach drift, was never built. Four photogrammetric restitutions from 2005, 2010, 2014 and 2017 and an aerial LiDAR in 2012 were obtained to better understand the previous topographic distribution of the back and foreshore. Numerous field observations were made, and six field surveys have been performed since 2018 using laser TLS and GNSS, which occurred in November 2018, March 2019, October 2019, March 2020, October 2020 and April 2021. The definitive results of the evolution of the sand loss are presented, a hypothesis is proposed to explain the dynamo-sedimentary trend, in which longitudinal transport dominates promoting the formation in the progress of a new sand beach, and some sustainable solutions are proposed. The results show that the constructive solution has failed to stabilize the beach and that the predictive models that justified it have not coincided with the real dynamic and sedimentary evolution. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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23 pages, 37659 KiB  
Article
Using UAV and Structure-From-Motion Photogrammetry for the Detection of Boulder Movement by Storms on a Rocky Shore Platform in Laghdira, Northwest Morocco
by Mouncef Sedrati, Juan A. Morales, Abdelmounim El M’rini, Edward J. Anthony, Glen Bulot, Romain Le Gall and Abdelkarim Tadibaght
Remote Sens. 2022, 14(16), 4102; https://doi.org/10.3390/rs14164102 - 21 Aug 2022
Cited by 12 | Viewed by 3124
Abstract
The detachment and mobilization of boulders from rocky shore platforms by waves involves complex geomorphic and hydrodynamic processes. Understanding these processes requires precise information on the rates and patterns of movement of these megaclasts scaled against the wave conditions that generate boulder mobility. [...] Read more.
The detachment and mobilization of boulders from rocky shore platforms by waves involves complex geomorphic and hydrodynamic processes. Understanding these processes requires precise information on the rates and patterns of movement of these megaclasts scaled against the wave conditions that generate boulder mobility. Repeat photogrammetry and structure-from-motion (SfM) models commonly used in geomorphic analyses are an interesting option for monitoring boulder dynamics. In this study, we used unmanned aerial vehicle (UAV)-based digital photogrammetry and SfM differential models to identify recent boulder movements over a rocky shore platform in Laghdira, Morocco. Combining these results with data on storm occurrence in the study area allowed us to identify storm waves as the unique driver of the dislodged and mobilized boulders. The identified storm event had a significant wave height of 5.2 m. The UAV models were built from imagery captured in September and December 2019 using a DJI MAVIC PRO PLATINUM, and we used QGIS to produce 2D and 3D model outputs. The exploitation of the 2D model differentials allowed us to appreciate the response of the boulders to the storm waves and to determine platform volumetric changes and, therefore, boulder mobility. The 3D models were valuable in determining the mode of transport of the boulders. Mobility patterns included sliding, overturning with no further mobility, and rotation and saltation, as well as boulder breakup. Storm waves did not have a preferential impact on any particular boulder shape, size category, or position at the outer edge of the platform. These results highlight the utility of combining UAV surveys with identified storm events, which are much more frequent than tsunamis, in determining observed boulder initiation and mobility. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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16 pages, 71089 KiB  
Article
Application of the Comparison of Multibeam Echo-Sound Records to the Study of Stability of a Toxic Waste Stockpile Located on the Margin of a Tidal System: Tinto Estuary, Huelva, SW Spain
by Berta M. Carro, Alejandro Reyes, Juan A. Morales and José Borrego
Remote Sens. 2021, 13(21), 4364; https://doi.org/10.3390/rs13214364 - 29 Oct 2021
Cited by 3 | Viewed by 2964
Abstract
For more than 40 years, the industrial complex which developed near Huelva (in SW Spain) produced a huge amount of phosphogypsum as a waste product of manufacturing fertilizers. This waste was stockpiled in a stack 25 m high, covering 1200 ha of what [...] Read more.
For more than 40 years, the industrial complex which developed near Huelva (in SW Spain) produced a huge amount of phosphogypsum as a waste product of manufacturing fertilizers. This waste was stockpiled in a stack 25 m high, covering 1200 ha of what was once a salt marsh. The weight of that enormous amount of waste produced active subsidence in the underlying sediment. Part of the sediment was injected into the marginal areas, where the load pressure is minor, causing significant vertical movement in the floor of the estuarine channel. This manuscript describes several surficial features using multibeam echosound. A crest formed by cones and a bulge area could be interpreted as injection structures. The evolution of the topographic position of the floor was also analyzed by comparing different records of the estuarine bed in the margins of the stockpile. The data in this work document the changes in the dynamics of the estuary in relation to these vertical movements. These changes in dynamicsled to erosion and deposition in various areas of the bed. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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21 pages, 11213 KiB  
Article
Sentinel-1 Data Processing for Detecting and Monitoring of Ground Instabilities in the Rocky Coast of Central Asturias (N Spain)
by José Cuervas-Mons, María José Domínguez-Cuesta, Félix Mateos Redondo, Anna Barra, Oriol Monserrat, Pablo Valenzuela and Montserrat Jiménez-Sánchez
Remote Sens. 2021, 13(16), 3076; https://doi.org/10.3390/rs13163076 - 5 Aug 2021
Cited by 5 | Viewed by 3062
Abstract
The cliff coastline of the central region of Asturias (N Spain) is severely affected by terrain instabilities, causing considerable damage to properties and infrastructures every year. In this study, we applied the A-DInSAR technique based on Sentinel-1 imagery to map and monitor active [...] Read more.
The cliff coastline of the central region of Asturias (N Spain) is severely affected by terrain instabilities, causing considerable damage to properties and infrastructures every year. In this study, we applied the A-DInSAR technique based on Sentinel-1 imagery to map and monitor active slopes in an emblematic rocky area of the Asturian coast: the Peñas Cape. The A-DInSAR dataset analysis has been focused at regional and local scales. For the local scale assessment, six areas were selected based on previous work and the landslide database of the Principality of Asturias region (BAPA-Base de datos de Argayos del Principado de Asturias), created by the University of Oviedo. The processing of the data has been performed using two independent sets of processing tools: the PSIG software tools, a professional tool and, the GEP service, an unsupervised platform. The dataset consisted of 113 SAR IW-SLC images acquired by the Sentinel-1 A/B satellites between January 2018 and February 2020. LOS mean deformation velocity maps (mm year−1) and deformation time series (mm) were obtained by PSIG and GEP software, allowing coastal areas with landslide incidence and other terrain movements to be distinguished. Deformation motion has been estimated from PSIG VLOS rates to be from −17.1 to 37.4 mm year−1 and GEP VLOS rates from −23.0–38.3 mm year−1. According to deformation time series (mm), the minimum and maximum accumulated displacements are −68.5–78.8 and −48.8–77.0 mm by means of PSIG and GEP, respectively. These ground motions could be associated with coastal instabilities related to marine activity and coastal retreat, both at regional and local study scales. The main contributions of this work are: (1) the demonstration of the potential of A-DInSAR techniques to evaluate coastal instabilities in a coastal retreat context and (2) the comparison of the results provided by the two sets of tools, which allowed the ground motion to be assessed by using an unsupervised approach vs. a contrasted one (robust software). This study increases the knowledge about coastal instabilities and other ground movements along the rocky coast and cliffs of Central Asturias. As a conclusion for the future, we believe that this work highlights the evaluated methods as significant tools to support the management of coastal territories with jagged and rocky coastlines. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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22 pages, 51861 KiB  
Article
3D Reconstruction of Coastal Cliffs from Fixed-Wing and Multi-Rotor UAS: Impact of SfM-MVS Processing Parameters, Image Redundancy and Acquisition Geometry
by Gil Gonçalves, Diogo Gonçalves, Álvaro Gómez-Gutiérrez, Umberto Andriolo and Juan Antonio Pérez-Alvárez
Remote Sens. 2021, 13(6), 1222; https://doi.org/10.3390/rs13061222 - 23 Mar 2021
Cited by 42 | Viewed by 4819
Abstract
Monitoring the dynamics of coastal cliffs is fundamental for the safety of communities, buildings, utilities, and infrastructures located near the coastline. Structure-from-Motion and Multi View Stereo (SfM-MVS) photogrammetry based on Unmanned Aerial Systems (UAS) is a flexible and cost-effective surveying technique for generating [...] Read more.
Monitoring the dynamics of coastal cliffs is fundamental for the safety of communities, buildings, utilities, and infrastructures located near the coastline. Structure-from-Motion and Multi View Stereo (SfM-MVS) photogrammetry based on Unmanned Aerial Systems (UAS) is a flexible and cost-effective surveying technique for generating a dense 3D point cloud of the whole cliff face (from bottom to top), with high spatial and temporal resolution. In this paper, in order to generate a reproducible, reliable, precise, accurate, and dense point cloud of the cliff face, a comprehensive analysis of the SfM-MVS processing parameters, image redundancy and acquisition geometry was performed. Using two different UAS, a fixed-wing and a multi-rotor, two flight missions were executed with the aim of reconstructing the geometry of an almost vertical cliff located at the central Portuguese coast. The results indicated that optimizing the processing parameters of Agisoft Metashape can improve the 3D accuracy of the point cloud up to 2 cm. Regarding the image acquisition geometry, the high off-nadir (90°) dataset taken by the multi-rotor generated a denser and more accurate point cloud, with lesser data gaps, than that generated by the low off-nadir dataset (3°) taken by the fixed wing. Yet, it was found that reducing properly the high overlap of the image dataset acquired by the multi-rotor drone permits to get an optimal image dataset, allowing to speed up the processing time without compromising the accuracy and density of the generated point cloud. The analysis and results presented in this paper improve the knowledge required for the 3D reconstruction of coastal cliffs by UAS, providing new insights into the technical aspects needed for optimizing the monitoring surveys. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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17 pages, 12229 KiB  
Article
Study and Evolution of the Dune Field of La Banya Spit in Ebro Delta (Spain) Using LiDAR Data and GPR
by Inmaculada Rodríguez-Santalla, David Gomez-Ortiz, Tomás Martín-Crespo, María José Sánchez-García, Isabel Montoya-Montes, Silvia Martín-Velázquez, Fernando Barrio, Jordi Serra, Juan Miguel Ramírez-Cuesta and Francisco Javier Gracia
Remote Sens. 2021, 13(4), 802; https://doi.org/10.3390/rs13040802 - 22 Feb 2021
Cited by 17 | Viewed by 3530
Abstract
La Banya spit, located at the south of the River Ebro Delta, is a sandy formation, developed by annexation of bars forming successive beach ridges, which are oriented and modeled by the eastern and southern waves. The initial ridges run parallel to the [...] Read more.
La Banya spit, located at the south of the River Ebro Delta, is a sandy formation, developed by annexation of bars forming successive beach ridges, which are oriented and modeled by the eastern and southern waves. The initial ridges run parallel to the coastline, and above them small dunes developed, the crests of which are oriented by dominant winds, forming foredune ridges and barchans. This study attempted to test a number of techniques in order to understand the dune dynamic on this coastal spit between 2004 and 2012: LiDAR data were used to reconstruct changes to the surface and volume of the barchan dunes and foredunes; ground-penetrating radar was applied to obtain an image of their internal structure, which would help to understand their recent evolution. GPS data taken on the field, together with application of GIS techniques, made possible the combination of results and their comparison. The results showed a different trend between the barchan dunes and the foredunes. While the barchan dunes increased in area and volume between 2004 and 2012, the foredunes lost thickness. This was also reflected in the radargrams: the barchan dunes showed reflectors related to the growth of the foresets while those associated with foredunes presented truncations associated with storm events. However, the global balance of dune occupation for the period 2004–2012 was positive. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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22 pages, 41176 KiB  
Article
Exploring the Relationship between River Discharge and Coastal Erosion: An Integrated Approach Applied to the Pisa Coastal Plain (Italy)
by Monica Bini, Nicola Casarosa and Marco Luppichini
Remote Sens. 2021, 13(2), 226; https://doi.org/10.3390/rs13020226 - 11 Jan 2021
Cited by 16 | Viewed by 3530
Abstract
Coastal erosion coupled with human-induced pressure has severely affected the coastal areas of the Mediterranean region in the past and continues to do so with increasing intensity today. In this context, the Pisa coastal plain shows a long history of erosion, which started [...] Read more.
Coastal erosion coupled with human-induced pressure has severely affected the coastal areas of the Mediterranean region in the past and continues to do so with increasing intensity today. In this context, the Pisa coastal plain shows a long history of erosion, which started at the beginning of the nineteenth century. In this work, shoreline positions derived from historical maps as well as airborne and DGPS (Differential Global Positioning System) surveys were analyzed in a GIS (Geographic Information System) environment to identify the main changes that have occurred in the last 142 years. These analyses were compared with 100 years of discharge data measured at the S. Giovanni alla Vena gauge to identify a possible correlation between the two sets of information. Finally, Sentinel-2 and Landsat images were studied to identify the dispersion of sediments transported by the Arno River. In particular, we found a minimum of fluvial discharge in the years 1954, 1978, and 2012 corresponding to a peak of erosion, while the reduced erosion rate and the fluvial discharge increased in the years 1928–1944, 1954–1975, and after 2012. The qualitative anticorrelation between discharge and erosion is particularly true if we take into account flood events with a value of discharge greater than 700 m3/s, which are those able to transport suspended sand. The remote sensing analyses of Sentinel-2 images acquired during the floods of 6 February 2019 and 3 December 2019, under the most typical wind and sea state conditions for this area (wind coming from SW and storms coming from W/SW and SW) show that during these events a consistent amount of sediment was transported by the river. However, the majority of these sediments are not deposited along the coastline but are dispersed offshore. Grain-size analyses on the transported sediment show that plumes are formed by coarse-to-medium sand, suitable for coastal nourishment, but the reconstructed sediment dispersion lines show that some sectors of the coastline are constantly in the shade. These areas are the most affected by erosion. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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18 pages, 5304 KiB  
Article
Interannual Response of Reef Islands to Climate-Driven Variations in Water Level and Wave Climate
by Michael V. W. Cuttler, Kilian Vos, Paul Branson, Jeff E. Hansen, Michael O’Leary, Nicola K. Browne and Ryan J. Lowe
Remote Sens. 2020, 12(24), 4089; https://doi.org/10.3390/rs12244089 - 14 Dec 2020
Cited by 24 | Viewed by 4354
Abstract
Coral reef islands are among the most vulnerable landforms to climate change. However, our understanding of their morphodynamics at intermediate (seasonal to interannual) timescales remains poor, limiting our ability to forecast how they will evolve in the future. Here, we applied a semi-automated [...] Read more.
Coral reef islands are among the most vulnerable landforms to climate change. However, our understanding of their morphodynamics at intermediate (seasonal to interannual) timescales remains poor, limiting our ability to forecast how they will evolve in the future. Here, we applied a semi-automated shoreline detection technique (CoastSat.islands) to 20 years of publicly available satellite imagery to investigate the evolution of a group of reef islands located in the eastern Indian Ocean. At interannual timescales, island changes were characterized by the cyclical re-organization of island shorelines in response to the variability in water levels and wave conditions. Interannual variability in forcing parameters was driven by El Niño Southern Oscillation (ENSO) cycles, causing prolonged changes to water levels and wave conditions that established new equilibrium island morphologies. Our results present a new opportunity to measure intermediate temporal scale changes in island morphology that can complement existing short-term (weekly to seasonal) and long-term (decadal) understanding of reef island evolution. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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16 pages, 5230 KiB  
Article
Assessing Reef Island Sensitivity Based on LiDAR-Derived Morphometric Indicators
by Joshua Louis Bonesso, Michael V.W. Cuttler, Nicola Browne, Jorg Hacker and Michael O’Leary
Remote Sens. 2020, 12(18), 3033; https://doi.org/10.3390/rs12183033 - 17 Sep 2020
Cited by 8 | Viewed by 5077
Abstract
Reef islands are some of the most highly sensitive landforms to the impacts of future environmental change. Previous assessments of island morphodynamics primarily relied on historical aerial and satellite imagery. These approaches limit analysis to two-dimensional parameters, with no ability to assess long-term [...] Read more.
Reef islands are some of the most highly sensitive landforms to the impacts of future environmental change. Previous assessments of island morphodynamics primarily relied on historical aerial and satellite imagery. These approaches limit analysis to two-dimensional parameters, with no ability to assess long-term changes to island volume or elevation. Here, we use high-resolution airborne LiDAR data to assess three-dimensional reef island features for 22 islands along the north-western coast of Australia. Our primary objective was to utilize two regional LiDAR datasets to identify characteristics indicative of island sensitivity and future vulnerability. Results show reef platform area to be an accurate predictor of island area and volume suggesting larger island volumes may reflect (1) increased carbonate production and supply from the reef platform and/or (2) enhanced shoreline protection by larger reef platforms. Locations of foredune scarping (an erosional signature) and island orientations were aligned to the regional wind and wave climate. Reef island characteristics (island area, volume, elevation, scarping, and platform area) were used to rank islands according to sensitivity, using a new Island Sensitivity Characteristics Index (ISCi) where low ISCi indicates stable islands (large areas and volumes, high elevations, and fewer scarped areas) and high ISCi indicates unstable islands (small areas and volumes, low elevations, and more scarped areas). Comparison of two LiDAR surveys from 2016 and 2018 validates the use of 3D morphometrics as important (direct) measurements of island landform change, and can complement the use of 2D parameters (e.g., area) moving forward. Results demonstrate that ongoing use of airborne LiDAR and other 3D technology for monitoring coral reef islands at regional scales will enable more accurate quantification of their sensitivity to future impacts of global environmental change. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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16 pages, 6402 KiB  
Technical Note
Nearshore Bathymetry Retrieval from Wave-Based Inversion for Video Imagery
by Diogo Santos, Tiago Abreu, Paulo A. Silva, Fábio Santos and Paulo Baptista
Remote Sens. 2022, 14(9), 2155; https://doi.org/10.3390/rs14092155 - 30 Apr 2022
Cited by 8 | Viewed by 2534
Abstract
A wavelet-based method for bathymetry retrieval using a sequence of static images of the surface wave field, as obtained from video imagery, is proposed. Synthetic images of the water surface are generated from a numerical Boussinesq type model simulating the propagation of irregular [...] Read more.
A wavelet-based method for bathymetry retrieval using a sequence of static images of the surface wave field, as obtained from video imagery, is proposed. Synthetic images of the water surface are generated from a numerical Boussinesq type model simulating the propagation of irregular waves. The spectral analysis is used to retrieve both wave periods and wavelengths by evaluating the spectral peaks in the time and spatial domains, respectively. The water depths are estimated using the linear dispersion relation and the results are validated with the model’s bathymetry. To verify the proposed methodology, 2D and 3D simulations considering effects of wave shoaling and refraction were performed for different sea conditions over different seafloors. The method’s ability to reproduce the original bathymetry is shown to be robust in intermediate and shallow waters, being also validated with a real case with images obtained with a shore-based video station. The main improvements of the new method compared to the consideration of a single image, as often used in Satellite Derived Bathymetry, is that the use of successive images enables the consideration of different wave periods, improving depth estimations and not requiring the use of subdomains or filters. This image processing methodology shows very positive results to provide bathymetry maps for shallow marine environments and can be useful to monitor the nearshore with high time- and space-resolution at low cost. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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15 pages, 3481 KiB  
Technical Note
On the 3D Reconstruction of Coastal Structures by Unmanned Aerial Systems with Onboard Global Navigation Satellite System and Real-Time Kinematics and Terrestrial Laser Scanning
by Diogo Gonçalves, Gil Gonçalves, Juan Antonio Pérez-Alvávez and Umberto Andriolo
Remote Sens. 2022, 14(6), 1485; https://doi.org/10.3390/rs14061485 - 19 Mar 2022
Cited by 15 | Viewed by 3012
Abstract
A wide variety of hard structures protect coastal activities and communities from the action of tides and waves worldwide. It is fundamental to monitor the integrity of coastal structures, as interventions and repairs may be needed in case of damages. This work compares [...] Read more.
A wide variety of hard structures protect coastal activities and communities from the action of tides and waves worldwide. It is fundamental to monitor the integrity of coastal structures, as interventions and repairs may be needed in case of damages. This work compares the effectiveness of an Unmanned Aerial System (UAS) and a Terrestrial Laser Scanner (TLS) to reproduce the 3D geometry of a rocky groin. The Structure-from-Motion (SfM) photogrammetry technique applied on drone images generated a 3D point cloud and a Digital Surface Model (DSM) without data gaps. Even though the TLS returned a 3D point cloud four times denser than the drone one, the TLS returned a DSM which was not representing about 16% of the groin (data gaps). This was due to the occlusions encountered by the low-lying scans determined by the displaced rocks composing the groin. Given also that the survey by UAS was about eight time faster than the TLS, the SFM-MV applied on UAS images was the most suitable technique to reconstruct the rocky groin. The UAS remote sensing technique can be considered a valid alternative to monitor all types of coastal structures, to improve the inspection of likely damages, and to support coastal structure management. Full article
(This article belongs to the Special Issue Advances in Remote Sensing in Coastal Geomorphology)
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