Academic literature on the topic 'Automated sounding selection'

<p><strong>Abstract.</strong> The compilation of nautical charts comprises a number of tasks that are often monotonous, time consuming, and, as such, prone to human error. A long-term goal of the hydrographic community has thus been the automation of the process due to the unquestionable advantages of automation to the accuracy, reliability, and consistency of products for a reduced cost-to-productivity ratio. One of the tasks that has received the attention of automation efforts is the compilation of bathymetry on charts and more precisely the generation and generalization of depth curves and the selection and validation of charted soundings. There is, however, much room for improvement with current methods.</p><p>Charted soundings and depth curves complement each other in maintaining and emphasizing the morphological details and characteristic features of the seafloor on charts. They are derived from a more detailed dataset, either survey data or a larger scale chart, with generalization. Once the cartographer delineates the depth curves, he/she makes the selection of soundings to be charted following established cartographic practice rules (see, e.g., IHO 2017; NOAA 2018). Both tasks may be performed either fully manually, or partially manually through a computer-assisted method.</p><p>The goal is for the cartographer to retain the morphology and the characteristic features of the seabed and at the same time to honor the overarching principle that the expected depth (based on the charted bathymetric information) must not appear, at any location, deeper than the source information. According to S-4 (IHO, 2017), for well surveyed areas the “shoal-biased” pattern of charted soundings is achieved through the “triangular method of selection”, where:<ol type="a"><li>No actual sounding exists within a triangle of selected soundings which is less than the least of any of the soundings defining the edges of the triangle (hereinafter: triangle test); and</li><li>No source sounding exists between two adjacent selected soundings forming an edge of the triangle which is less than the lesser of the two selected soundings (hereinafter: edge test).</li></ol><p>Motivated by the need for automated tools that perform consistently and satisfactorily in every geographic situation, and in the context of a developing project for a fully automated solution in nautical chart production, this paper presents our research work on the development of a comprehensive solution for the validation of the shoal-biased pattern of charted bathymetric information. This includes an algorithmic implementation of the triangle test that eliminates the false positives of previous implementation efforts near and within linear features (see Figure 1), as well as the first automated implementation of the edge test in the literature. For the above implementations we incorporate the available bathymetric information on the chart, e.g., coastlines (natural and man-made), depth curves, soundings, obstructions, and wrecks (see Kastrisios and Calder 2018; Kastrisios et al. 2019).</p><p>The presented work also illustrates the importance of the edge test in the validation of the charted bathymetric information as it can identify shoals that the triangle test may not identify (see Figure 2), thereby proving that the edge test must not be disregarded by cartographers in the validation process.</p><p>However, the two tests share the intrinsic limitation of missing discrepancies between the charted and source bathymetric information, even if they are significant (see Figure 3). Thus, a fully automated solution based on a verbatim interpretation of the two tests as written in S-4 does not seem feasible. Therefore, we propose a surface-based validation test that will account - at the appropriate charting resolution - for the configuration of the seabed that would be mentally reconstructed by the mariner from the charted bathymetric information. This is expected to lead to a more realistic representation of the submarine relief and its navigationally significant features on charts from the available source information (see Kastrisios et al. 2019).</p>

Introduction. The reliability of geomechanical prediction depends on the level of detail of databases covering geological structure, geometry and physical properties of the rock mass under investigation. In order to improve the accuracy of coal pit wall stability prediction, following the generalization of databases containing geological survey, groundwater monitoring, geophysical sounding and mine surveying, it is advisable to construct three-dimensional geological-geophysical models accounting for the main adverse factors, and thereafter search for the most hazardous section. Research aim is to predict wall stability according to the developed algorithm based on the threedimensional geological-geophysical model. Research methodology includes a search for the most hazardous rock mass site section by the ratio between shear and retaining forces within the established zones with anomalous physical characteristics. Results. By generalizing databases containing geological studies, groundwater monitoring, geophysical sounding by the method of electrical resistivity tomography, and mine surveying, a three-dimensional geological- geophysical model has been constructed of a wall loaded with “heap of dry rock atop of the hydraulic dump” man-made structure and undermined by underground works. The trial site stability has been predicted for the true state of mining. Comparative analysis of the obtained data has been carried out. Summary. The combination of natural and man-made factors, including hydrogeological conditions of the territory, seasonal and climatic behavior, tectonic faulting of the deposit and shear zones connected with undermining result in the development of a rather complex geological structure of the wall which includes local deconsolidated and waterlogged zones significantly reducing the stability of the pit slope. At the trial site of Kedrovsky pit due to spatial and temporal alternation of properties and state of rock within the landslide hazardous zone, the variation range of the factor of safety in six typical sections amounts n = 1.06–2.39. For that reason the objective prediction of slope stability in similar conditions (in addition to geological survey and hydrogeological observations data analysis) should include geophysical monitoring of anomalous zones origination and development, hereupon creation of a treedimensional geological-physical model, and the automated calculation of the factor of safety including repeated selection of the most hazardous section.

On nautical charts, undersea features are portrayed by sets of soundings (depth points) and isobaths (depth contours) from which map readers can interpret landforms. Different techniques were developed for automatic soundings selection and isobath generalisation from a sounding set. These methods are mainly used to generate a new chart from the bathymetric database or from a large scale chart through selection and simplification however a part of the process consists in selecting and emphasising undersea features on the chart according to their relevance to navigation. Its automation requires classification of the features from the set of isobaths and soundings and their generalisation through the selection and application of a set of operators according not only to geometrical constraints but also to semantic constraints. <br><br> The objective of this paper is to define an ontology formalising undersea feature representation and the generalisation process achieving this representation on a nautical chart. The ontology is built in two parts addressing on one hand the definition of the features and on the other hand their generalisation. The central concept is the undersea feature around which other concepts are organised. The generalisation process is driven by the features where the objective is to select or emphasise information according to their meaning for a specific purpose. The ontologies were developed in Protégé and a bathymetric database server integrating the ontology was implemented. A generalisation platform was also developed and examples of representations obtained by the platform are presented. Finally, current results and on-going research are discussed.

Timely and accurate identification of change detection for areas depicted on nautical charts constitutes a key task for marine cartographic agencies in supporting maritime safety. Such a task is usually achieved through manual or semi-automated processes, based on best practices developed over the years requiring a substantial level of human commitment (i.e., to visually compare the chart with the new collected data or to analyze the result of intermediate products). This work describes an algorithm that aims to largely automate the change identification process as well as to reduce its subjective component. Through the selective derivation of a set of depth points from a nautical chart, a triangulated irregular network is created to apply a preliminary tilted-triangle test to all the input survey soundings. Given the complexity of a modern nautical chart, a set of feature-specific, point-in-polygon tests are then performed. As output, the algorithm provides danger-to-navigation candidates, chart discrepancies, and a subset of features that requires human evaluation. The algorithm has been successfully tested with real-world electronic navigational charts and survey datasets. In parallel to the research development, a prototype application implementing the algorithm was created and made publicly available.

AbstractWe present a novel automated processing method for obtaining layer dip from radio-echo sounding (RES) data. The method is robust, easily applicable and can be used to process large (several terabytes) ground and airborne RES datasets using modest computing resources. We give test results from the application of the method to two Antarctic datasets: the Fletcher Promontory ground-based radar dataset and the Wilkes Subglacial Basin airborne radar dataset. The automated RES processing (ARESP) method comprises the basic steps: (1) RES noise reduction; (2) radar layer identification; (3) isolation of individual ‘layer objects’; (4) measurement of orientation and other object properties; (5) elimination of noise in the orientation data; and (6) collation of the valid dip information. The apparent dip datasets produced by the method will aid glaciologists seeking to understand ice-flow dynamics in Greenland and Antarctica: ARESP could enable a shift from selective regional case studies to ice-sheet-scale studies.

The accuracy of field/process reconstruction from the field/process measurement data at the nodes of the space-time lattice is the main quality criterion for the control system. Due to the unreliability of the system, information from the lattice nodes is lost, which is equivalent to its thinning. There is an analytical connection between the error in the field representation and the number of nodes operating with a known probability. Approximate formulas estimating the increment of the error in the representation of processes and fields with power-law spectra with a decrease in the number of nodes N of the space-time lattice for are proposed. Real control systems are multichannel and retain partial useful operability in the event of a failure of a certain number of channels, i.e. they are redundant. Formulas for calculating the reliability of redundant shipborne sounding and towed devices, automatic buoy stations with meters on the horizons and with distributed thermopiles are derived. Towed systems, coastal stations and autonomous buoy stations should operate as long as possible. To build durable systems, the results obtained earlier in the theory of reliability by the author on the ineffectiveness of the static reserve, the fundamental inappropriateness of external diagnostics of faults by observing the inputs and outputs of devices, the possibility of ideal diagnostics of faults by replacing from the dynamic reserve are used. This is the only known method that provides optimal and ideal diagnostics of malfunctions regardless of the structure of the systems and, therefore, allows you to build recoverable and arbitrarily durable systems. The diagnostic method by replacing from the reserve in the software implementation is extended to a set of nodes of the space-time lattice for selecting information from the environment.

O conhecimento do fundo marinho é um fator crucial para a segurança da navegação, assim como para as diversas atividades marítimas. O progresso da hidrografia tem mostrado novos horizontes trazendo diversos sistemas complexos que prometem resolver muitos dos desafios nesta área. Respetivamente à aquisição de dados batimétricos através de sondadores de feixe-simples, este trabalho surge da necessidade de colmatar os erros dependentes do fator humano, reduzir o tempo de processamento e melhorar a qualidade do mesmo. Para tal, são necessárias ferramentas computacionais que auxiliem a fase de processamento de dados e a elaboração de produtos finais. Deste modo, foi criada uma ferramenta, com auxílio a vários algoritmos e métodos desenvolvidos. Um dos utilizados é o Self Organizing Map (SOM) ou mapas auto-organizados. O estudo apresenta, sinteticamente, conceitos básicos de Levantamentos Hidrográficos para uma melhor compreensão dos dados analisados. De seguida, apresenta-se o modo de funcionamento do algoritmo SOM, abordando aspetos necessários para a realização de agrupamento de dados (clustering) como parte da solução da ferramenta desenvolvida. A partir deste, apresenta-se a metodologia desenvolvida para a realização da seleção de dados (sondas) necessária à criação de produtos para representação do fundo marinho. A ferramenta desenvolvida, Processamento de Dados Garmin com Self-Organizing Map (PDGSOM), é confrontada com outros sistemas de processamento de dados batimétricos, nomeadamente o software CARIS. Deste modo, comparando modelos batimétricos realizou-se uma análise de parâmetros de funcionamento e eficácia da ferramenta desenvolvida. Em síntese, a presente dissertação tem como objetivo a construção de uma ferramenta com uma interface de fácil utilização, fornecendo uma informação segura na utilização dos dados e produtos obtidos, tendo como motivo de estudo a “segurança na navegação”.
The need of knowledge of the seabed in its whole, has been brought many challenges to maritime navigation. The safety of navigation is a crucial factor, and even with all the progress and the new horizons that hydrography science has shown with its numerous complex systems, there are still many obstacles to overcome. Regarding the acquisition of bathymetric data with single beam echo sounder, this work arises from the need to bridge the errors reflected on the human factor, improve the processing of data acquisition and time reduction. For all the reasons stated above, computational tools are of a main importance on the data processing phase and the elaboration of final products. For this study, I developed a tool, using Decision Support System, based on the algorithm of self-organizing map Kohonen. Better known for its clustering, visualization and classification capabilities with comprehensive solutions for selection of bathymetric data. The study begins by presenting, the basic concepts for a better understanding of the studied area, with respect to the Hydrographic Surveys. Next, the operation of the Self Organizing Map algorithm is presented, addressing aspects necessary to perform data grouping (clustering) as part of the solution of the developed tool. From this, I present the methodology used to develop the realization of data selection necessary to create products for representing the seabed. The developed tool, Garmin Data Processing with Self-Organizing Map (PDGSOM - Portuguese version) is compared with other bathymetric data processing systems, CARIS software. This allowed the comparison of digital elevation models, analysis of operation parameters and effectiveness of the developed tool. Succinctly, this dissertation has as main goal the construction of a tool with an easy-use interface, providing safe information in the use of the data and obtained products, based on the principles of "safety of navigation ".