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| Long, N.; Millescamps, B.; Pouget, F.; Dumon, A.; Lachaussee, N.; Bertin, X.. |
| To monitor coastal environments, Unmanned Aerial Vehicle (UAV) is a low-cost and easy to use solution to enable data acquisition with high temporal frequency and spatial resolution. Compared to Light Detection And Ranging (LiDAR) or Terrestrial Laser Scanning (TLS), this solution produces Digital Surface Model (DSM) with a similar accuracy. To evaluate the DSM accuracy on a coastal environment, a campaign was carried out with a flying wing (eBee) combined with a digital camera. Using the Photoscan software and the photogrammetry process (Structure From Motion algorithm), a DSM and an orthomosaic were produced. Compared to GNSS surveys, the DSM accuracy is estimated. Two parameters are tested: the influence of the methodology (number and distribution of... |
| Tipo: Text |
Palavras-chave: Digital Surface Model; Coastal monitoring; UAV photogrammetry; Accuracy. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00668/78011/80248.pdf |
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| Jaud, Marion; Letortu, Pauline; Augereau, Emmanuel; Le Dantec, Nicolas; Beauverger, Mickael; Cuq, Veronique; Prunier, Christophe; Le Bivic, Rejanne; Delacourt, Christophe. |
| The georeferencing process is crucial to the accuracy of terrestrial laser scanner (TLS) data, in particular in the context of diachronic studies relying on multi-temporal surveys. The use of Ground Control Points in the georeferencing process can however be complex when confronted with the practical constraints of coastal surveying. A simple and quick alternative method called "pseudo-direct georeferencing" is proposed in the present paper. This method involves internal inclinometers to measure roll and pitch angles and a centimetric GPS to measure the position of the TLS center and the position of one backsight target. When assessing the transformational uncertainty by using a set of independent ground validation points for both classical indirect and... |
| Tipo: Text |
Palavras-chave: Terrestrial laser scanning; Coastal monitoring; Direct georeferencing; Indirect georeferencing; Multi-temporal surveys; Geomorphological evolution. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75050/75683.pdf |
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| Caruana, Amandine; Ayache, Nour; Raimbault, Virginie; Rétho, Michael; Hervé, Fabienne; Bilien, Gwenael; Amzil, Zouher; Chomérat, Nicolas. |
| We confirm an amnesic shellfish poisoning risk associated with domoic acid production by the species Pseudo-nitzschia plurisecta and determine the toxin profile, which includes three domoic acid isomers. Although the species was reported once in European waters, along the Spanish Atlantic coast, here we describe and characterize P. plurisecta collected during the first occurrence in French Atlantic waters. Three strains (IFR-PPL-15.1, 15.2 and 15.3) were isolated from French coastal water samples in June 2015. These strains were identified and characterized by microscopic observation, molecular (ITS region sequencing and phylogenetic analysis) and metabolite (toxins and pigments) analyses. The cell shape is lanceolate and the valve contains a central... |
| Tipo: Text |
Palavras-chave: Coastal monitoring; Domoic acid; Pigment composition; Pseudo-nitzschia plurisecta; Taxonomic identification; Toxic diatoms. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00505/61687/66033.pdf |
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| Long, Nathalie; Millescamps, Bastien; Guillot, Benoit; Pouget, Frederic; Bertin, Xavier. |
| Unmanned Aerial Vehicles (UAVs) are being increasingly used to monitor topographic changes in coastal areas. Compared to Light Detection And Ranging (LiDAR) data or Terrestrial Laser Scanning data, this solution is low-cost and easy to use, while allowing the production of a Digital Surface Model (DSM) with a similar accuracy. Three campaigns were carried out within a three-month period at a lagoon-inlet system (Bonne-Anse Bay, La Palmyre, France), with a flying wing (eBee) combined with a digital camera. Ground Control Points (GCPs), surveyed by the Global Navigation Satellite System (GNSS) and post-processed by differential correction, allowed georeferencing DSMs. Using a photogrammetry process (Structure From Motion algorithm), DSMs and orthomosaics... |
| Tipo: Text |
Palavras-chave: UAV photogrammetry; Coastal monitoring; Tidal inlet; Sandspit. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00668/78010/80247.pdf |
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| Jaud, Marion; Kervot, Matthieu; Delacourt, Christophe; Bertin, Stephane. |
| With recent advances in photogrammetric processing methods and sensor technologies, smartphones represent a new opportunity of mainstream, low-cost sensor, with a great potential for Structure-from-Motion (SfM) photogrammetry, and in particular for participatory science programs or citizen observatories. Keeping in mind the application in citizen observatories, three smartphone models (Galaxy S7 (R), Lumia 930 (R) and iPhone 8 (R)) and a bridge camera were compared (separately and in combination) for coastal applications: A coastal cliff and a sandy beach. Various acquisition protocols, at different distances from a cliff face and using "linear" or "fan-shaped" capture mode, were also assessed in their efficiency. A simultaneous Terrestrial Laser Scanner... |
| Tipo: Text |
Palavras-chave: Smartphone; SfM photogrammetry; Coastal monitoring; DEM; Citizen observatory. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74907/76115.pdf |
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| Jaud, Marion; Grasso, Florent; Le Dantec, Nicolas; Verney, Romaric; Delacourt, Christophe; Ammann, Jerome; Deloffre, Julien; Grandjean, Philippe. |
| Intertidal mudflats play a critical role in estuarine exchange, connecting marine and continental supplies of nutrients and sediments. However, their complex morphodynamics, associated with a wide range of physical and biological processes, are still poorly understood and require further field investigation. In addition, mudflats are challenging areas for Structure-from-Motion (SfM) photogrammetric surveys. Indeed, the mudflats generally hold back residual tidal water, which can make stereo restitution particularly difficult because of poor correlations or sun-glint effects. This study aims to show the potential of light UAVs (Unmanned Aerial Vehicles) for monitoring sedimentary hydrodynamics at different spatial scales in a silty estuary. For each UAV... |
| Tipo: Text |
Palavras-chave: Coastal monitoring; Unmanned Aerial Vehicle; Photogrammetry; Estuary; Mudflat areas; Morphological features. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00326/43721/43167.pdf |
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| Gohin, Francis; Bryère, Philippe; Lefebvre, Alain; Sauriau, Pierre-guy; Savoye, Nicolas; Vantrepotte, Vincent; Bozec, Yann; Cariou, Thibault; Conan, Pascal; Coudray, Sylvain; Courtay, Gaelle; Françoise, Sylvaine; Goffart, Anne; Hernández Fariñas, Tania; Lemoine, Maud; Piraud, Aude; Raimbault, Patrick; Rétho, Michael. |
| The consistency of satellite and in situ time series of Chlorophyll-a (Chl-a), Turbidity and Total Suspended Matters (TSM) was investigated at 17 coastal stations throughout the year 2017. These stations covered different water types, from relatively clear waters in the Mediterranean Sea to moderately turbid regions in the Bay of Biscay and the southern bight of the North-Sea. Satellite retrievals were derived from MODIS/AQUA, VIIRS/NPP and OLCI-A/Sentinel-3 spectral reflectance. In situ data were obtained from the coastal phytoplankton networks SOMLIT (CNRS), REPHY (Ifremer) and associated networks. Satellite and in situ retrievals of the year 2017 were compared to the historical seasonal cycles and percentiles, 10 and 90, observed in situ. Regarding the... |
| Tipo: Text |
Palavras-chave: Satellite; Coastal monitoring; Chlorophyll-a; Total suspended matter; Turbidity. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00645/75669/76536.pdf |
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