Pub Date : 2022-01-22DOI: 10.1080/01490419.2022.2032497
Evangelos Alevizos, T. Le Bas, D. Alexakis
Abstract Currently, several satellite-derived bathymetry (SDB) workflows are based on a variety of satellite imagery which are analyzed by empirical or analytical methods. The latest availability of PRISMA hyperspectral data provides a new opportunity for testing their application in shallow water bathymetry mapping. Here we utilize two Level-2 PRISMA scenes from the Caribbean Sea capturing seafloor areas with diverse benthic features and we analyze them using the shallow water analytical models provided by the water-color simulator (WASI) software. The presented study examines the influence of spatial resolution and end-member spectra on the SDB output. Consequently, in one study area we apply inversion using additional reference spectra and in the other study area we exploit the PRISMA panchromatic band for producing a pan-sharpened, hyperspectral cube for bathymetry inversion. The results show good correlation with reference bathymetry data (sonar and admiralty chart) suggesting that PRISMA imagery has a clear potential in optical bathymetry studies. The use of appropriate end-member spectra assists in enhancing the accuracy of SDB, and pan-sharpened PRISMA imagery assists in improving the results when detailed bathymetry is required. PRISMA imagery can be effectively analyzed with open-source software WASI-2D and thus contribute new bathymetric data to regional-scale seafloor mapping projects.
{"title":"Assessment of PRISMA Level-2 Hyperspectral Imagery for Large Scale Satellite-Derived Bathymetry Retrieval","authors":"Evangelos Alevizos, T. Le Bas, D. Alexakis","doi":"10.1080/01490419.2022.2032497","DOIUrl":"https://doi.org/10.1080/01490419.2022.2032497","url":null,"abstract":"Abstract Currently, several satellite-derived bathymetry (SDB) workflows are based on a variety of satellite imagery which are analyzed by empirical or analytical methods. The latest availability of PRISMA hyperspectral data provides a new opportunity for testing their application in shallow water bathymetry mapping. Here we utilize two Level-2 PRISMA scenes from the Caribbean Sea capturing seafloor areas with diverse benthic features and we analyze them using the shallow water analytical models provided by the water-color simulator (WASI) software. The presented study examines the influence of spatial resolution and end-member spectra on the SDB output. Consequently, in one study area we apply inversion using additional reference spectra and in the other study area we exploit the PRISMA panchromatic band for producing a pan-sharpened, hyperspectral cube for bathymetry inversion. The results show good correlation with reference bathymetry data (sonar and admiralty chart) suggesting that PRISMA imagery has a clear potential in optical bathymetry studies. The use of appropriate end-member spectra assists in enhancing the accuracy of SDB, and pan-sharpened PRISMA imagery assists in improving the results when detailed bathymetry is required. PRISMA imagery can be effectively analyzed with open-source software WASI-2D and thus contribute new bathymetric data to regional-scale seafloor mapping projects.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42260802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-12DOI: 10.1080/01490419.2022.2027831
N. Tunalioglu, T. Ocalan, Ali Hasan Doğan
Abstract In the next generation, the use of dual-frequency Embedded GNSS Chipset in the smart devices, which will be widely used in engineering applications, has been used for the first time in Xiaomi Mi8. Considering this development dynamics, a kinematic test was carried out in the marine environment monitoring with a geodetic GNSS receiver and an android smartphone in Turkey Oyak Port. According to the results of the test, RMSE for horizontal coordinate components were found as 0.0423 m and 5.9493 m for reference solution and PPP-AR solution of geodetic receiver, and reference solution and PPP solution of smartphone, respectively. Moreover, the positional errors of individual epochs were computed as 0.0411 m and 4.6871 m with respect to given order. The solution obtained from Xiaomi Mi8 raw GNSS data with PPP approach provides the Order 2 for hydrographic survey standards IHO S-44 in terms of Total Horizontal Uncertainty (THU).
{"title":"Precise Point Positioning with GNSS Raw Measurements from an Android Smartphone in Marine Environment Monitoring","authors":"N. Tunalioglu, T. Ocalan, Ali Hasan Doğan","doi":"10.1080/01490419.2022.2027831","DOIUrl":"https://doi.org/10.1080/01490419.2022.2027831","url":null,"abstract":"Abstract In the next generation, the use of dual-frequency Embedded GNSS Chipset in the smart devices, which will be widely used in engineering applications, has been used for the first time in Xiaomi Mi8. Considering this development dynamics, a kinematic test was carried out in the marine environment monitoring with a geodetic GNSS receiver and an android smartphone in Turkey Oyak Port. According to the results of the test, RMSE for horizontal coordinate components were found as 0.0423 m and 5.9493 m for reference solution and PPP-AR solution of geodetic receiver, and reference solution and PPP solution of smartphone, respectively. Moreover, the positional errors of individual epochs were computed as 0.0411 m and 4.6871 m with respect to given order. The solution obtained from Xiaomi Mi8 raw GNSS data with PPP approach provides the Order 2 for hydrographic survey standards IHO S-44 in terms of Total Horizontal Uncertainty (THU).","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46447702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-11DOI: 10.1080/01490419.2022.2025503
Mohsen H. Shahraji, C. Larouche
Abstract Accurate infrastructure monitoring of ports and harbors is a vital operation conducted by the port’s authority. To operate regularly in this highly dynamic environment, we explore the potential of the cutting-edge mobile LiDAR systems (MLS) mounted on a vessel. To generate a high-quality 3 D point cloud that would satisfy the expected accuracy required in the monitoring task, the LiDAR scanner and the positioning and orientation system (POS) must be angularly aligned also known as boresight alignment. In this research, we introduce a boresight alignment methodology adapted to the port infrastructure surveillance based on prefabricated planar targets. After an analysis of planar target simulated data, we propose a boresight alignment site design. Then, we apply this boresight alignment site design in a real-world scenario. Obtained results estimate accurately roll and yaw angles errors with standard deviations of less than 0.002 degrees and pitch angle error with standard deviation less than 0.015 degrees. Finally, we defined a validation site and described the procedure that uses these features to validate the quality of the estimated parameters. The relative comparison of the georeferenced point clouds, before and after boresight alignment demonstrates the mitigation of the boresight systematic error impact on the final point cloud.
{"title":"Case Study: Rigorous Boresight Alignment of a Marine Mobile LiDAR System Addressing the Specific Demands of Port Infrastructure Monitoring","authors":"Mohsen H. Shahraji, C. Larouche","doi":"10.1080/01490419.2022.2025503","DOIUrl":"https://doi.org/10.1080/01490419.2022.2025503","url":null,"abstract":"Abstract Accurate infrastructure monitoring of ports and harbors is a vital operation conducted by the port’s authority. To operate regularly in this highly dynamic environment, we explore the potential of the cutting-edge mobile LiDAR systems (MLS) mounted on a vessel. To generate a high-quality 3 D point cloud that would satisfy the expected accuracy required in the monitoring task, the LiDAR scanner and the positioning and orientation system (POS) must be angularly aligned also known as boresight alignment. In this research, we introduce a boresight alignment methodology adapted to the port infrastructure surveillance based on prefabricated planar targets. After an analysis of planar target simulated data, we propose a boresight alignment site design. Then, we apply this boresight alignment site design in a real-world scenario. Obtained results estimate accurately roll and yaw angles errors with standard deviations of less than 0.002 degrees and pitch angle error with standard deviation less than 0.015 degrees. Finally, we defined a validation site and described the procedure that uses these features to validate the quality of the estimated parameters. The relative comparison of the georeferenced point clouds, before and after boresight alignment demonstrates the mitigation of the boresight systematic error impact on the final point cloud.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42978508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-30DOI: 10.1080/01490419.2021.2020185
A. Zaki, Mahmoud Magdy, M. Rabah, A. Saber
Abstract For the purpose of marine geoid modeling and many other geodetic and geophysical applications, a marine gravity map around Egypt is established by the integration of gravity data provided by satellite altimetry and shipborne gravimetric observations. Firstly, the collected shipborne data were compared with GO_CONS_GCF_2_TIM_R6 and XGM2019e GGMs and with SSv29.1 and DTU17 altimetry models. Then, a pre-refinement of ship marine surveys was done with a rigorous condition, in which a number of 6525 points have been removed from the dataset. After that, 87709 points were deducted from the pre-filtered shipborne dataset to fit the study area and the cross-validation approach with the kriging interpolation algorithm were applied. A rigorous level of confidence was decided in this step where the points which have differences between the estimated and the observed values more than twice the STD of the residuals were removed until the STD reached a value less than 1 mGal. Finally, the filtered shipborne gravity data were combined with DTU17 (the best evaluation model) using the least-squares collocation technique (LSC). The final gravity map was tested using 8000 randomly chosen shipborne stations, which were not included when applying LSC, revealing the significant enhancement gained after the integration process.
{"title":"Establishing a Marine Gravity Database around Egypt from Satellite Altimetry-Derived and Shipborne Gravity Data","authors":"A. Zaki, Mahmoud Magdy, M. Rabah, A. Saber","doi":"10.1080/01490419.2021.2020185","DOIUrl":"https://doi.org/10.1080/01490419.2021.2020185","url":null,"abstract":"Abstract For the purpose of marine geoid modeling and many other geodetic and geophysical applications, a marine gravity map around Egypt is established by the integration of gravity data provided by satellite altimetry and shipborne gravimetric observations. Firstly, the collected shipborne data were compared with GO_CONS_GCF_2_TIM_R6 and XGM2019e GGMs and with SSv29.1 and DTU17 altimetry models. Then, a pre-refinement of ship marine surveys was done with a rigorous condition, in which a number of 6525 points have been removed from the dataset. After that, 87709 points were deducted from the pre-filtered shipborne dataset to fit the study area and the cross-validation approach with the kriging interpolation algorithm were applied. A rigorous level of confidence was decided in this step where the points which have differences between the estimated and the observed values more than twice the STD of the residuals were removed until the STD reached a value less than 1 mGal. Finally, the filtered shipborne gravity data were combined with DTU17 (the best evaluation model) using the least-squares collocation technique (LSC). The final gravity map was tested using 8000 randomly chosen shipborne stations, which were not included when applying LSC, revealing the significant enhancement gained after the integration process.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48218934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-16DOI: 10.1080/01490419.2021.2011502
Jichao Wang, Yue Wang
Abstract Significant wave height (SWH) is a vital parameter in marine science research and engineering application. The up-to-date reanalysis product ERA5 SWH brings new possibilities to the long-term analysis. However, a systematic assessment of ERA5 SWH on a large scale is still lacking. This paper presents an evaluation of ERA5 SWH against observations from 103 buoys in the North American Atlantic and Pacific sourced by the National Data Buoy Center over the period 1979 to 2019. Overall, the ERA5 SWH has a good agreement with the in-situ observations, with a bias of −0.058 m, root mean squared error of 0.325 m, correlation coefficient of 0.961 and scatter index of 18.54%. The accuracy of ERA5 SWH is satisfactory under the most typical sea states (0.5 m < SWH < 4 m). The monthly analysis shows the performance of ERA5 SWH in summer is the best. The water depth and offshore distance have also been identified to impact the reliability of ERA5 SWH. Although the statistics vary at different locations, the performances of ERA5 SWH at most stations are reasonable. In addition, an evident improvement in the validity over time is observed, which can be attributed to the assimilation of the altimeter wave height.
{"title":"Evaluation of the ERA5 Significant Wave Height against NDBC Buoy Data from 1979 to 2019","authors":"Jichao Wang, Yue Wang","doi":"10.1080/01490419.2021.2011502","DOIUrl":"https://doi.org/10.1080/01490419.2021.2011502","url":null,"abstract":"Abstract Significant wave height (SWH) is a vital parameter in marine science research and engineering application. The up-to-date reanalysis product ERA5 SWH brings new possibilities to the long-term analysis. However, a systematic assessment of ERA5 SWH on a large scale is still lacking. This paper presents an evaluation of ERA5 SWH against observations from 103 buoys in the North American Atlantic and Pacific sourced by the National Data Buoy Center over the period 1979 to 2019. Overall, the ERA5 SWH has a good agreement with the in-situ observations, with a bias of −0.058 m, root mean squared error of 0.325 m, correlation coefficient of 0.961 and scatter index of 18.54%. The accuracy of ERA5 SWH is satisfactory under the most typical sea states (0.5 m < SWH < 4 m). The monthly analysis shows the performance of ERA5 SWH in summer is the best. The water depth and offshore distance have also been identified to impact the reliability of ERA5 SWH. Although the statistics vary at different locations, the performances of ERA5 SWH at most stations are reasonable. In addition, an evident improvement in the validity over time is observed, which can be attributed to the assimilation of the altimeter wave height.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46796619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-15DOI: 10.1080/01490419.2021.2006376
Shailee Patel, Manisha Vithalpura, S. Mallick, S. Ratheesh
Abstract This study investigates the response of a high resolution coupled physical-ecosystem model simulations to initial and boundary conditions (IBCs) from various sources. For this purpose, we used physical parameters from the data sets World Ocean Atlas (WOA09), CSIRO Atlas of Regional Seas (CARS09) and North Indian Ocean Atlas (NIOA). Evaluating model simulated fields with standard validation data suggests that all three experiments could resolve most of the known surface and subsurface features of the Bay of Bengal (BoB) but with considerable differences in salinity and chlorophyll-a (Chl-a) and negligible differences in temperature among model simulations with various IBCs. The modeled Chl-a is well simulated with WOA09 as compared to NIOA and CARS09 data for climatological model simulations, with a correlation of 0.52 for the BoB. Moreover, the vertical distribution of Chl-a is found to be a function of nutrient supply to the base of the euphotic layer and mixed layer. These results significantly highlight the implicit and explicit use of IBCs for better representation of Chl-a concentration in the BoB from a high-resolution coupled model.
{"title":"Impact of Initial and Boundary Conditions on Coupled Model Simulations for Bay of Bengal","authors":"Shailee Patel, Manisha Vithalpura, S. Mallick, S. Ratheesh","doi":"10.1080/01490419.2021.2006376","DOIUrl":"https://doi.org/10.1080/01490419.2021.2006376","url":null,"abstract":"Abstract This study investigates the response of a high resolution coupled physical-ecosystem model simulations to initial and boundary conditions (IBCs) from various sources. For this purpose, we used physical parameters from the data sets World Ocean Atlas (WOA09), CSIRO Atlas of Regional Seas (CARS09) and North Indian Ocean Atlas (NIOA). Evaluating model simulated fields with standard validation data suggests that all three experiments could resolve most of the known surface and subsurface features of the Bay of Bengal (BoB) but with considerable differences in salinity and chlorophyll-a (Chl-a) and negligible differences in temperature among model simulations with various IBCs. The modeled Chl-a is well simulated with WOA09 as compared to NIOA and CARS09 data for climatological model simulations, with a correlation of 0.52 for the BoB. Moreover, the vertical distribution of Chl-a is found to be a function of nutrient supply to the base of the euphotic layer and mixed layer. These results significantly highlight the implicit and explicit use of IBCs for better representation of Chl-a concentration in the BoB from a high-resolution coupled model.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42505934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-13DOI: 10.1080/01490419.2021.2013355
P. Bonnefond, O. Laurain, P. Exertier, M. Calzas, T. Guinle, N. Picot
Abstract The geodetic Corsica site was set up in 1998 in order to perform altimeter calibration of the TOPEX/Poseidon (T/P) mission and subsequently, Jason-1, OSTM/Jason-2, Jason-3 and more recently Sentinel-6 Michael Freilich (launched on November, 21 2020). The aim of the present study held in June 2015 is to validate a recently developed GNSS-based sea level instrument (called CalNaGeo) that is designed with the intention to map Sea Surface Heights (SSH) over large areas. This has been undertaken using the well-defined geodetic infrastructure deployed at Senetosa Cape, and involved the estimation of the stability of the waterline (and thus the instantaneous separation of a GNSS antenna from water level) as a function of the velocity at which the instrument is towed. The results show a largely linear relationship which is approximately 1 mm/(m/s) up to a maximum practical towing speed of ∼10 knots (∼5 m/s). By comparing to the existing “geoid” map, it is also demonstrated that CalNaGeo can measure a sea surface slope with a precision better than 1 mm/km (∼2.5% of the physical slope). Different processing techniques are used and compared including GNSS Precise Point Positioning (PPP, where the goal is to extend SSH mapping far from coastal GNSS reference stations) showing an agreement at the 1-2 cm level.
科西嘉测量站建立于1998年，目的是对TOPEX/Poseidon (T/P)任务以及随后的Jason-1、OSTM/Jason-2、Jason-3和最近的Sentinel-6 Michael Freilich(于2020年11月21日发射)进行高度计校准。本研究于2015年6月进行，目的是验证最近开发的基于gnss的海平面仪器(称为CalNaGeo)，该仪器旨在绘制大面积的海面高度(SSH)。这是使用部署在塞内托萨角的定义明确的大地测量基础设施进行的，并涉及估计水线的稳定性(因此GNSS天线与水位的瞬时分离)，作为仪器拖曳速度的函数。结果显示了一个很大程度上的线性关系，大约为1毫米/(米/秒)，直到最大实际拖曳速度为~ 10节(~ 5米/秒)。通过与现有的“大地水准面”地图进行比较，还证明CalNaGeo可以以优于1 mm/km(物理坡度的约2.5%)的精度测量海面坡度。使用并比较了不同的处理技术，包括GNSS精确点定位(PPP，其目标是将SSH映射扩展到远离沿海GNSS参考站的地方)，显示出1-2厘米水平的一致性。
{"title":"Validating a New GNSS-Based Sea Level Instrument (CalNaGeo) at Senetosa Cape","authors":"P. Bonnefond, O. Laurain, P. Exertier, M. Calzas, T. Guinle, N. Picot","doi":"10.1080/01490419.2021.2013355","DOIUrl":"https://doi.org/10.1080/01490419.2021.2013355","url":null,"abstract":"Abstract The geodetic Corsica site was set up in 1998 in order to perform altimeter calibration of the TOPEX/Poseidon (T/P) mission and subsequently, Jason-1, OSTM/Jason-2, Jason-3 and more recently Sentinel-6 Michael Freilich (launched on November, 21 2020). The aim of the present study held in June 2015 is to validate a recently developed GNSS-based sea level instrument (called CalNaGeo) that is designed with the intention to map Sea Surface Heights (SSH) over large areas. This has been undertaken using the well-defined geodetic infrastructure deployed at Senetosa Cape, and involved the estimation of the stability of the waterline (and thus the instantaneous separation of a GNSS antenna from water level) as a function of the velocity at which the instrument is towed. The results show a largely linear relationship which is approximately 1 mm/(m/s) up to a maximum practical towing speed of ∼10 knots (∼5 m/s). By comparing to the existing “geoid” map, it is also demonstrated that CalNaGeo can measure a sea surface slope with a precision better than 1 mm/km (∼2.5% of the physical slope). Different processing techniques are used and compared including GNSS Precise Point Positioning (PPP, where the goal is to extend SSH mapping far from coastal GNSS reference stations) showing an agreement at the 1-2 cm level.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43403790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-12DOI: 10.1080/01490419.2021.1993386
S. D. Dao, Antoine Mallégol, P. Meyer, Mehrdad Mohammadi, S. Loyer
Abstract Hydrographic surveying is a necessary task in the maritime community, which can contribute to maritime security, economic development, scientific research, and environmental protection. Hydrographic surveying is a regular and costly activity; hence, careful hydrographic survey planning is required. Hydrographic survey routing is one of the main tasks in hydrographic survey planning, in which we not only need to find the most interesting maritime area(s) (usually evaluated through a risk measure, aggregating navigation risk, environmental impact, and/or data obsolescence), but also the shortest route to do the hydrographic surveying. In this article, first, we attempt to formulate the hydrographic survey routing problem and then develop an efficient hybrid iterated greedy algorithm to solve the problem. The proposed algorithm consists of three stages, that is, Stage 1 with a memetic algorithm to find a good starting point, Stage 2 with a global greedy algorithm to explore the global search space, and Stage 3 with a local greedy algorithm to exploit the local search space. Five real case studies in France are conducted to validate the performance of the developed algorithm.
{"title":"A Hybrid Iterated Greedy Algorithm for Hydrographic Survey Routing Problem","authors":"S. D. Dao, Antoine Mallégol, P. Meyer, Mehrdad Mohammadi, S. Loyer","doi":"10.1080/01490419.2021.1993386","DOIUrl":"https://doi.org/10.1080/01490419.2021.1993386","url":null,"abstract":"Abstract Hydrographic surveying is a necessary task in the maritime community, which can contribute to maritime security, economic development, scientific research, and environmental protection. Hydrographic surveying is a regular and costly activity; hence, careful hydrographic survey planning is required. Hydrographic survey routing is one of the main tasks in hydrographic survey planning, in which we not only need to find the most interesting maritime area(s) (usually evaluated through a risk measure, aggregating navigation risk, environmental impact, and/or data obsolescence), but also the shortest route to do the hydrographic surveying. In this article, first, we attempt to formulate the hydrographic survey routing problem and then develop an efficient hybrid iterated greedy algorithm to solve the problem. The proposed algorithm consists of three stages, that is, Stage 1 with a memetic algorithm to find a good starting point, Stage 2 with a global greedy algorithm to explore the global search space, and Stage 3 with a local greedy algorithm to exploit the local search space. Five real case studies in France are conducted to validate the performance of the developed algorithm.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48302724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-08DOI: 10.1080/01490419.2021.1992546
D. M, V. S., S. S. A., M. K
Abstract A shoreline change analysis has been carried out for the coastal stretch from Ennore creek to Karungali village located along the southeast coast of India. This 15 km-long coastal stretch had undergone significant changes such as erosion and accretion concerning infrastructure developments and leading to large impact on the livelihood of the community. To assess the shoreline changes, the analysis of multi-temporal satellite images has been carried out. A historical trend is established for the study period from 1991 to 2019. The analysis has been made in three timelines considering various developing activities. There was no significant coastal infrastructure development during 1991 to 1999; however, between 1999 and 2009, a major port, pier, and a groyne field were constructed. Additionally, a port was established between 2009 and 2019. Erosion was observed on the coast from Kattupalli to Karungali at a rate of −16.85 m/yr since 2009, while the coast on the south of Ennore port is accreting at the rate of +12.43 m/yr during the same period. The near-future projection using a linear regression model shows further erosion in the coast under similar conditions. The results of this study provide a baseline data for future anthropogenic activities along this coast.
{"title":"Historical Shoreline Analysis and Field Monitoring at Ennore Coastal Stretch along the Southeast Coast of India","authors":"D. M, V. S., S. S. A., M. K","doi":"10.1080/01490419.2021.1992546","DOIUrl":"https://doi.org/10.1080/01490419.2021.1992546","url":null,"abstract":"Abstract A shoreline change analysis has been carried out for the coastal stretch from Ennore creek to Karungali village located along the southeast coast of India. This 15 km-long coastal stretch had undergone significant changes such as erosion and accretion concerning infrastructure developments and leading to large impact on the livelihood of the community. To assess the shoreline changes, the analysis of multi-temporal satellite images has been carried out. A historical trend is established for the study period from 1991 to 2019. The analysis has been made in three timelines considering various developing activities. There was no significant coastal infrastructure development during 1991 to 1999; however, between 1999 and 2009, a major port, pier, and a groyne field were constructed. Additionally, a port was established between 2009 and 2019. Erosion was observed on the coast from Kattupalli to Karungali at a rate of −16.85 m/yr since 2009, while the coast on the south of Ennore port is accreting at the rate of +12.43 m/yr during the same period. The near-future projection using a linear regression model shows further erosion in the coast under similar conditions. The results of this study provide a baseline data for future anthropogenic activities along this coast.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41709499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-19DOI: 10.1080/01490419.2021.1992547
Wenlong Yang, S. Xue, Yixu Liu
Abstract The computational efficiency of underwater acoustic positioning based on the ray tracing is mainly limited to a great amount of calculation of ray inverse problem. We propose two kinds of p-order secant methods to improve the efficiency of traditional method, and the proposed methods can be regarded as a generalization of the traditional secant method from two points to p points for rapidly solving the inverse problem. In the proposed methods, the calculation information in previous iterations is utilized to fit a polynomial model to speed up the algorithm convergence. In the first-kind method, the inverse problem is calculated by solving a polynomial equation approximating the function mapping from the emission angle to the radial distance of the ray. In the second-kind method, the inverse problem is however directly solved by approximating the function mapping from the radial distance to the emission angle. As the first-kind method needs to solve a p-order polynomial equation, the practicability of this method is limited to the complexity of solving the high-order equation, while the second-kind method can directly approximate the solution of the inverse problem, which is more practical and flexible. The proposed methods have been verified in deep-sea trial. It shows that, the proposed methods can precisely produce the solution of the acoustic ray inverse problem within one iteration, and the computational efficiency of proposed method is about 6 times faster than that of the traditional method.
{"title":"P-Order Secant Method for Rapidly Solving the Ray Inverse Problem of Underwater Acoustic Positioning","authors":"Wenlong Yang, S. Xue, Yixu Liu","doi":"10.1080/01490419.2021.1992547","DOIUrl":"https://doi.org/10.1080/01490419.2021.1992547","url":null,"abstract":"Abstract The computational efficiency of underwater acoustic positioning based on the ray tracing is mainly limited to a great amount of calculation of ray inverse problem. We propose two kinds of p-order secant methods to improve the efficiency of traditional method, and the proposed methods can be regarded as a generalization of the traditional secant method from two points to p points for rapidly solving the inverse problem. In the proposed methods, the calculation information in previous iterations is utilized to fit a polynomial model to speed up the algorithm convergence. In the first-kind method, the inverse problem is calculated by solving a polynomial equation approximating the function mapping from the emission angle to the radial distance of the ray. In the second-kind method, the inverse problem is however directly solved by approximating the function mapping from the radial distance to the emission angle. As the first-kind method needs to solve a p-order polynomial equation, the practicability of this method is limited to the complexity of solving the high-order equation, while the second-kind method can directly approximate the solution of the inverse problem, which is more practical and flexible. The proposed methods have been verified in deep-sea trial. It shows that, the proposed methods can precisely produce the solution of the acoustic ray inverse problem within one iteration, and the computational efficiency of proposed method is about 6 times faster than that of the traditional method.","PeriodicalId":49884,"journal":{"name":"Marine Geodesy","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44242204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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