Digital Nautical Chart Research Articles

Evaluation of Digital Nautical Chart data for confirmation and expansion of GeoNames data

ABSTRACT This work examines how Digital Nautical Chart (DNC) data may contribute to the evolution and refinement of GeoNames data for near-shore features. GeoNames features are point data with one or more possible place names. DNC Earth Cover Text (ECRText) objects are map labels positioned nearby their real word counterpart. ECRText feature map position strikes a compromise between association with real features and cartographic readability. This work explores whether ECRText features can confirm (or expand names for) existing locations or contribute new locations through data conflation. Due to name variations and spatial position, conflating these data are nontrivial. Previous work engaged in a brief examination using the trigram string matching algorithm under coarse proximity constraints, indicating that ECRText could provide additional value to GeoNames. This work builds on that study, by engaging in a deeper examination of spatial proximity and exploring conflation agreement across an ensemble of string matching approaches. The result finds strong ensemble agreement about ECRText features which already exist in GeoNames but mixed results about which features contribute new information, as well as exploring why some of these matching techniques fail. With an eye toward automation, computational efficiency was found not to be a constraint in sustaining updates.

MARS: An Augmented Reality-Based Marine Chart Display System

The visualization system of nautical charts enhances the safety navigation on sea, particularly in critical areas. Nowadays nautical chart visualization technology considers the benefit of inventive information technology to produce three-dimensional and real-time models which can be easily used. Therefore, this study attempted to develop an Android-based application with Augmented Reality (AR) approach. A digitation of the conventional nautical chart was performed to build a digital nautical chart. This process implemented regulation from United States (US) Chart No. 1 and International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) Maritime Buoyage System. There are two substantial results of this research: Marine Augmented Reality System (MARS) to display a nautical chart in a three-dimensional form, and Marine Augmented Reality System GPS (MARSGPS) which focuses on integrating the model with its vicinity environment. This brings users to better acknowledge the situation of their environment. The usability test of these products shows that the overall feasibility value is 83.71%. The coordinate accuracy of MARSGPS application has a Root Mean Square Error (RMSE) value of 4.30m, which can be improved through a ground-truth measurement. Nevertheless, this approach provides an essential reference for future research on a three-dimensional nautical chart visualization.

A Study on the Creation of High Density Depth Contours in Coastal Waters using Spatial Analysis based on Depth and AIS Data

ECDIS provides safety function related to depth and contour lines to prevent grounding of ship. However, since the most ENCs contain depth contours at intervals of 2, 5, 10, 20, 30m, it is difficult to provide precise information to users and have limitations as a function of anti-grounding. Recently, the IHO recognized this problem and recommended the production of HD(High Density) ENC that provides depth contours at 1m intervals in confined water. In this study, spatial analysis was performed based on AIS and marine accident data to determine the depth contour ranges and areas required for HD ENC production. The study area was selected near Incheon and Pyeongtaek port on the west coast of Korea and depth contour lines with 1m intervals were created based on the TIN(Triangulated Irregular Network) interpolation algorithm and DEM(Digital Elevation Model) using the water depth data of the digital nautical chart. After that, the distribution of ship’s draft was analyzed based on the AIS data, and the spatial autocorrelation analysis using marine accident data indicates the need to provide dense contour lines in the fairway of Incheon and Pyeongtaek. It is expected to HD ENC that reflects the environment of the area and the characteristics of ships can help safe navigation of ships and prevent marine accidents.

Testbed Scenario Design Exploiting Traffic Big Data for Autonomous Ship Trials Under Multiple Conflicts With Collision/Grounding Risks and Spatio-Temporal Dependencies

Autonomous ships are promoted as the future of the maritime transport industry aiming to overcome conventional vessels in terms of performance, safety and environmental impact. Yet their tangled cyber-physical-social interactions and new emerging properties induce questions regarding their liability and trustworthiness. Digital simulations and sea trials are launched to assure the safety requirements and social expectations are met a priori. This paper presents the design of realistic testbed scenarios from huge historical data through a high-performance computational method to recommend a complete set of navigation scenarios for autonomy tests. The developed approach integrates traffic big data from Automatic Identification System (AIS) with high-resolution digital maps, vessel information registry, and digital nautical charts. All historical vessel-to-ground and vessel-to-vessel interactions are efficiently analyzed through a hierarchical method for collision and grounding conflicts assessment with a 15-minutes prediction horizon. Relative risk is evaluated accurately over full periods of predicted close-quarters situations subject to physical limits and sea-room availability for evasive maneuverers under COLREG rules and traffic separation schemes. Spatial dependencies among multiple conflicts define risky momentary traffic situations modelled through directed graph representation of nested interactions. Their temporal dependencies describe navigation scenarios through dynamic co-behaviors between multiple participating vessels over a period of time. Finally, we analyze negative/positive actions that increase/decrease the complexity. The presented algorithms are computationally very efficient, they scale to several (country*year)s where millions of scenarios are extracted, classified, and scored by their relative risk, complexity, and likelihood for firm post-test conclusions.

Set of Data Elements for Nautical Charts Cataloging: Analysis Between the RDA Scheme and the IDERA Metadata Profile

The nautical chart is a cartographic resource designed to meet the requirements of maritime navigation, showing the depth of the water and the nature of the seabed, as well as the configuration, features and elevation of the coast and the dangers and aids to navigation. The nautical charts provide a graphic representation of the information required by the navigator to carry out safe navigation. The organization and description of this type of resources is a key element when accessing information. From the scope of librarianship, the current scheme for the processing of information is the RDA standards Resource, description and access), which allow the description of all kinds of information resources. On the other hand, geospatial organizations have developed different specific metadata schemes for the processing of spatial information. Metadata allows a producer to describe a dataset fully so that users can understand the assumptions and limitations and evaluate the dataset's applicability for their intended use. In Argentina, the scheme for processing this kind of information is called IDERA, which is based on the ISO 19115: Standards on geographic information. The present work analyzes the treatment that specific rules of metadata like IDERA and general norms of description of resources like RDA give to the set of specific data present in the digital nautical charts. Methodology: from the identification of data elements that allow to describe and identify nautical charts as information resources a comparative table between both schemes was developed. Results: Neither of the two schemes has contemplated the totality of data element set established for the identification of nautical charts. The RDA scheme managed to better satisfy the description and identification of nautical charts that IDERA, although neither of them contemplate 100% the established data elements set. Conclusions and recommendations: 1) According to the above, neither of the two schemes to process the information complies in its entirety with the information contained in the nautical charts. 2) Some data elements do not fit in any of the two schemes, reducing visibility and information retrieval of the two schemes for processing information, RDA are those that allow a more complete description of the resource, although in a general, non-specific way. 3) The specialized spatial data scheme (IDERA) leaves out important data elements of this kind of resources. 4) IDERA metadata profile, although it was thought for spatial data does not include the special characteristics of the different resources that make it up. 5) It is advisable to develop a metadata profile that, in addition to contemplating the general characteristics of geospatial resources, includes the particularities of each class of its resources

Automatic Sounding Generalization in Nautical Chart Considering Bathymetry Complexity Variations

ABSTRACTSounding acts as the main feature in a digital nautical chart as it describes the concerned marine topography for the safety of navigation. Unlike the geometry-oriented selection of point feature, the generalization of soundings for chart compiling is expected to be context-oriented, which means bathymetry complexity variations across the study region should be preserved in the sounding selection process. However, such variations are not explicitly accessible to automated systems. This paper proposes an approach that effectively analyzes and measures bathymetry complexity from sounding data, with a focus on topography variations among different regions. The presented approach first divides the exploring region into several subregions, by adopting techniques of computational geometry and graph theory. Then, the approach quantitatively measures the bathymetry complexity of the subregions from grid-based digital terrain model. Finally, a composite bathymetry complexity index integrating aspects of steepness and depth variation is developed to guide the operation of sounding selection in different subregions. Generally, when seafloor is rugged with steep slopes, the number of soundings is high. While in flatter areas, a smaller amount of soundings is retained. The potential of our approach is demonstrated by an application to a real data set.

Evolution analysis of Chongming Dongtan wetland in recent 60 years based on digital nautical chart and remote sensing

The spatial variation of Chongming Dongtan wetland was monitored using 10 remote sensing images including Landsat MSS,TM and ETM+ data.Nine nautical charts were employed to analyze the evolution of underwater terrain from 1951 to 2006.With the above/under water topographic changes as an entirety,the authors made quantitative and qualitative analysis of geomorphic evolution in the past 60 years at Chongming Dongtan wetland using waterline method and depth contour overlaying.Some conclusions have been reached: ① The dynamics of Chongming Dongtan tend to be stable,characterized by erosion in the south part,deposition in the north,rapid propagation in the middle and alternate erosion and deposition in some coasts under the stabilities of the current Yangtze estuary;② Human activities made important effect on the wetland.Especially,damn in the Baigang tidal channel accelerated deposition in the wetland.Then the 0 m isobath expanded to the east at a stable rate.Although the wetland area was increasing with the human reclamation year by year,the inter-tidal structure of wetland was deviated from the nature state.The proportion of high tidal flat was decreasing and it showed discontinuous spatial distribution at Chongming Dongtan.Because the damn was directly exposed to the outside marine environment,it would reduce the capability of disaster weather prevention.

A Study on Fusion and Visualization using Multibeam Sonar Data with Various Spatial Data Sets for Marine GIS

According to the remarkable advances in sonar technology, positioning capabilities and computer processing power we can accurately image and explore the seafloor in hydrography. Especially, Multibeam Echo Sounder can provide nearly perfect coverage of the seafloor with high resolution. Since the mid-1990's, Multibeam Echo Sounders have been used for hydrographic surveying in Korea. In this study, new marine data set as an effective decision-making tool in various fields was proposed by visualizing and combining with Multibeam sonar data and marine spatial data sets such as satellite image and digital nautical chart. The proposed method was tested around the port of PyeongTaek-DangJin in the west coast of Korea. The Visualization and fusion methods are described with various marine data sets with processing. We demonstrated that new data set in marine GIS is useful in safe navigation and port management as an efficient decision-making tool.

Multiscale ENC Data Management on an Archipelagic Sea Area – Example of the East Adriatic Coast

This paper briefly outlines the production of electronic nautical charts (ENC) as a digital nautical chart, produced by the Croatian National Hydrographic Office (HO) to International Hydrographic Organization (IHO) specifications S-57 Edition 3.1. The production of ENCs is based on the theory of multiscale data management (usage bands). Multiple representations of ENC data are controlled by scale minimum (SCAMIN) attributes. A solution to the problem of multiscale data management as a part of ENC data production for archipelagic sea areas, using the East Adriatic Coast as an example is presented. This solution is based on a long-standing experience in the production of paper charts and recent ENC production for the eastern coast of the Adriatic Sea, which is believed to be the second largest archipelagic area in the Mediterranean. Finally, a new usage band scale range, compilation scale for all navigational purposes and method of using SCAMIN attributes for archipelagic seas are proposed.

Recognition and Measurement of Marine Topography for Sounding Generalization in Digital Nautical Chart

Generalization is a comprehensive process. It is not simply a question of an algorithm, such as simplification, selection, displacement, and so on. Only after geometric shapes and topological properties have been understood fully, can a sound and automated generalization process be possible. This article proposes a new theoretical model for sounding generalization in digital nautical charts. First, with the aid of Delaunay triangulation, a tree structure is introduced for a hierarchical representation of the marine topography. Then, an analytical algorithm for the recognition and the measurement of the marine topography is developed through the use of the tree structure. Finally, all of the techniques mentioned above are integrated into a model for sounding generalization, of which results are illustrated with the aid of several examples. Haigang Sui, Lab for Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, 129 Luoyu Road, Wuhan, Hubei, 430079, China E-mail: lulatian@public.tpt.tj.cn

ORVPF – the Model and its DNC Implementation

Vector Product Format (VPF) based databases store geographical data in a relational framework, where individual VPF files are arranged hierarchically in a directory tree structure. Access and update of the VPF data can become difficult due to fragmentation of data among multiple tables. This paper presents an object-oriented model for the management of a VPF database, which provides easy access and automatic update for the VPF data, and is compatible with ESRI ArcView. This model has been successfully implemented in Java, for Digital Nautical Charts (DNC).

The Navigation Sensor System Interface Project

The AN/SSN-6 Navigation Sensor System Interface (NAVSSI) Project is a new system being designed with two primary objectives; to serve as the central distribution computer for navigation data to shipboard combat/weapon systems and to serve as the electronic chart display and information system (ECDIS). The NAVSSI will operate the digital nautical chart (DNC) database being developed by the Defense Mapping Agency (DMA). Our goal is for the digital nautical chart to replace the paper chart as a legal means of ownship navigation plotting. This paper will introduce the project and will primarily explore the use of digital nautical charts for ownship navigation with NAVSSI.

The Navigation Sensor System Interface Project

ABSTRACTThe AN/SSN‐6 Navigation Sensor System Interface (Nav‐SSI) Project is a new system being designed with two primary objectives; processing/distribution of navigation data and the display/operation of digital nautical charts. NavSSI will be the United States Navy Electronic Chart Display & Information System (ECDIS), meaning naval vessels can navigate using NavSSI for ownship plotting instead of the traditional paper nautical charts. This paper will present the background on the project and provide a technical description of the hardware and software architecture. The Digital Nautical Chart (DNC) database will be described with special focus on the technical specifications and the NavSSI operational software using DNC. There will be a brief discussion of the legal concerns of using an electronic navigation chart instead of the paper nautical chart. There are still many key issues regarding the DNC database to be resolved and these will be presented.