Research on Three-Dimensional Electronic Navigation Chart Hybrid Spatial Index Structure Based on Quadtree and R-Tree

The purpose of this study is to propose an approach to fuse multiscale charts into three-dimensional (3D) electronic navigational chart (ENC) systems based on underwater topography and remote sensing image. This is the first time that the fusion of multiscale standard ENCs in the 3D ENC system has been studied. First, a view-dependent visualization technology is presented for the determination of the display condition of a chart. Second, a map sheet processing method is described for dealing with the map sheet splice problem. A process order called “3D order” is designed to adapt to the characteristics of the chart. A map sheet clipping process is described to deal with the overlap between the adjacent map sheets. And our strategy for map sheet splice is proposed. Third, the rendering method for ENC objects in the 3D ENC system is introduced. Fourth, our picking-up method for ENC objects is proposed. Finally, we implement the above methods in our system: automotive intelligent chart (AIC) 3D electronic chart display and information systems (ECDIS). And our method can handle the fusion problem well.

This article presents technology for the production of electronic navigational charts (ENC) in the Hydrographie Institute of the Republic of Croatia (HIRC); current conditions of producing ENC cells and comparison with international experiences. ENC database together with GPS and onboard sensors make up -electronic chart display and information system (ECDIS) navigational GIS. The purpose of ENC and ECDIS is improvement of navigational safety and protection of marine environment. HIRC is participant of the international pilot project "North Adriatic virtual regional electronic nautical chart" (VRENC), deals with standardization in production and distribution of ENCs covering the area of the North Adriatic Sea. In international relations HIRC has a rather satisfying ENC production

Electronic navigational charts (ENCs) are geospatial databases compiled in strict accordance with the technical specifications of the International Hydrographic Organization (IHO). Electronic Chart Display and Information System (ECDIS) is a Geographic Information System (GIS) operated by ENCs for real-time navigation at sea, which is one of the key technologies for intelligent ships to realize autonomous navigation, intelligent decision-making, and other functions. Facing the urgent demand for high-precision and real-time nautical chart products for polar navigation under the new situation, the projection of ENCs for polar navigation is systematically analyzed in this paper. Based on the theory of complex functions, we derive direct transformations of Mercator projection, polar Gauss-Krüger projection, and polar stereographic projection. A rational set of dynamic projection options oriented towards polar navigation is proposed with reference to existing specifications for the compilation of the ENCs. From the perspective of nautical users, rather than the GIS expert or professional cartographer, an ENCs visualization idea based on multithread-double buffering is integrated into Polar Region Electronic Navigational Charts software, which effectively solves the problem of large projection distortion in polar navigation applications. Taking the CGCS2000 reference ellipsoid as an example, the numerical analysis shows that the length distortion of the Mercator projection is less than 10% in the region up to 74°, but it is more than 80% at very high latitudes. The maximum distortion of the polar Gauss-Krüger projection does not exceed 10%. The degree of distortion of the polar stereographic projection is less than 1% above 79°. In addition, the computational errors of the direct conversion formulas do not exceed 10−9 m throughout the Arctic range. From the point of view of the computational efficiency of the direct conversion model, it takes no more than 0.1 s to compute nearly 8 million points at 1′×1′ resolution, which fully meets the demand for real-time nautical chart products under information technology conditions.

It is seen that high technology and its products work to meet every stage and need of human life and navigational safety in the maritime sector. Electronic systems have been developed and are used today as a result of the search for alternatives to the well-known and approved classical methods used in safe navigation on the world's seas. Electronic systems are susceptible and more accurate than classical methods and significantly benefit maritime transport. Bridge electronic systems and infrastructures supporting its components also work with advanced technology products. In this context, electronic navigational charts - ENC, Electronic Chart Display Information systems - ECDIS and Automatic Information systems - AIS are undoubtedly the best examples. These and similar bridge and auxiliary devices ensure the safety of navigation on both national and international seas and oceans and cause a decrease in human error rates. This study mentions the positive effects of high-tech bridge navigation systems developed in the maritime sector on maritime transportation.

Cartographic sounding selection is a constraint-based bathymetric generalization process for identifying navigationally relevant soundings for nautical chart display. Electronic Navigational Charts (ENCs) are the premier maritime navigation medium and are produced according to international standards and distributed around the world. Cartographic generalization for ENCs is a major bottleneck in the chart creation and update process, where high volumes of data collected from constantly changing seafloor topographies require tedious examination. Moreover, these data are provided by multiple sources from various collection platforms at different levels of quality, further complicating the generalization process. Therefore, in this work, a comprehensive sounding selection algorithm is presented that focuses on safe navigation, leveraging both the Digital Surface Model (DSM) of multi-source bathymetry and the cartographic portrayal of the ENC. A taxonomy and hierarchy of soundings found on ENCs are defined and methods to identify these soundings are employed. Furthermore, the significant impact of depth contour generalization on sounding selection distribution is explored. Incorporating additional ENC bathymetric features (rocks, wrecks, and obstructions) affecting sounding distribution, calculating metrics from current chart products, and introducing procedures to correct cartographic constraint violations ensures a shoal-bias and mariner-readable output. This results in a selection that is near navigationally ready and complementary to the specific waterways of the area, contributing to the complete automation of the ENC creation and update process for safer maritime navigation.

Nautical cartography competences and their effect to the realisation of a worldwide Electronic Navigational Charts database, the performance of ECDIS and the fulfilment of IMO chart carriage requirements

Electronic navigational charts (ENCs) are geospatial databases, compiled for the operational use of Electronic Chart Display and Information systems (ECDIS) according to strict technical specifications of the International Hydrographic Organization (IHO). ECDIS is a GIS system designed for marine navigation according to the relevant standards of the International Maritime Organization (IMO). The international standards for ENCs and ECDIS, issued by the IHO and IMO, cover many aspects of the portrayal of ENCs in ECDIS but do not specify or recommend map projections. Consequently, in some cases, the unjustified employment of map projections by the manufacturers has caused certain functional drawbacks and inadequacies. This article reviews, evaluates and supplements the results of earlier studies on the selection of map projections for the depiction of ENCs in ECDIS and proposes a reasonable set of suitable projections with pertinent selection/implementation rules. These proposals took into consideration that ECDIS users (navigators) are not GIS experts or professional cartographers and consequently, the proposed election/implementation rules have to be simple and straightforward.

The paper presents the problem of determining a safe ship trajectory in real conditions with the use of information comprised in electronic navigational charts (ENC). Ship trajectory optimisation is one of essential functionalities of decision support systems which are part of intelligent transport systems. An ENC data transformation method herein presented is aimed to reduce the time of creating the numerical terrain model for an optimization problem. Trapezoidal meshes are proposed for this purpose. Water area parameters as well as moving targets are considered. The three dimensional ship domain is used as a safety criterion. The implementation of the presented method is discussed.

This study introduces an assessment concerning the use of Electronic Chart Display and Information System (ECDIS) in the safe navigation of vessels by considering the case studies whether the device played a role in grounding accidents. A total 80 investigation reports of grounding accidents from 2008 to 2018 were analysed. In 22 cases, one or more findings related to ECDIS and Electronic Navigational Charts (ENC) were identified. Twenty two accidents related to ECDIS or ENCs were re-analysed with 4M Overturned Pyramid (MOP) model to determine the characteristics and causes of accidents. Causative factors that related ECDIS in the cases have been listed and explained. Results indicate that ECDIS-related procedures and lack of training have led to incorrect settings of the device, especially alarm settings. The recommendations have been arranged that ECDIS devices, which offer much considerable information for the safe navigation of ships, are able to work more efficiently.

Currently the International Maritime Organization (IMO) is taking the lead in developing e-navigation as an information service framework. E-navigation supports sharing, harmonization and utilization of various marine and marine-related data both shipboard and onshore. Recently, the IMO adopted the International Hydrographic Organization (IHO)'s S-100 as the basis of the Common Maritime Data Structure (CMDS) of e-navigation. Thus, the various data are to be provided to e-navigation services in formats consistent with the S-100 data model. E-navigation services, in order to provide appropriate information to users, utilize and harmonize many kinds of S-100-based data such as Electronic Navigation Chart (ENC) data, bathymetric data, tidal data, meteorology data, radar-image data, and Automatic Identification System (AIS) data. In e-navigation, data management systems dealing with S-100-based data facilitate e-navigation services' harmonization and utilization of the various S-100-based data. In this paper, we present an S-100 data management system that deals with various S-100-based data. We designed the system by generalization of the System ENC (SENC) kernel that manages S-101 ENC data. For development of a data management system that supports the management of various kinds of S-100-based data, we analyzed the characteristics of the S-100 data model and S-100-based data products. The S-100 data management system is designed to store S-100-based feature-oriented geographic data in the form of pairs.

E-navigation Services for Non-SOLAS Ships

Abstract. Advancements in geospatial technology have benefited the hydrographic and maritime professions in many ways. Yet, compared to hydrographic data collection and processing, chart compilation workflows remain relatively slow, mainly due to limited human resources and the availability of automated algorithms that respect nautical charting constraints and Electronic Navigational Chart (ENC) database requirements. This work presents our research efforts to streamline the nautical chart compilation process through the introduction of automated processes and improving the efficiency and accuracy of existing. Among these processes are fundamental generalization tasks such as those for soundings, islands, and depth contours; ENC product specific requirements, such as those for reducing file size through the removal of collinear vertices forming polylines and polygons; and the updating of dependent features in the ENC database after generalization of one of their shared geometries.

The depth is important for vessel navigation at sea. Currently, most vessels use electronic navigation charts to navigate at sea. In coastal areas, especially close to shallow water areas, the dynamic change of the water level is very important to safe navigation. Ships calculate the change of water level by using up-to-date tide tables, to obtain the dynamic water depth in the channels. However, the depth caused by the tide and non-tidal components may reach several meters in some seas, causing the dynamic depth below the safety depth, which can easily lead to grounding of vessels stranding accidents. The channel is regularly dredged to achieve navigational depth. Without regular dredging, the offshore non-channel area becomes the common area of ship grounding. The dynamic chart depth model studied in this article can provide real-time depth, which serves the ships navigation in the non-channel. The model incorporates the chart depth and the dynamic water levels on the same reference datum. The chart depth is from the electronic navigational chart depth. The dynamic water levels are constructed by the simulated tidal levels and continuous series of nontidal residual. We then designed a deviation correction method to reduce the discrepancy of the simulated tidal level with the actual water level, including datum offset correction and residual water level correction. Finally, by merging the revised dynamic water levels with the electronic navigational chart depth, we obtained the dynamic chart depth model of the study region.

Bathymetric data quality on Electronic Navigational Charts (ENCs) is encoded with the Category Zone of Confidence (CATZOC) providing information about horizontal and vertical uncertainty, seabed coverage, and feature detection. To support safe navigation, the nautical charting community has been investigating improved methods for the inclusion of data quality on charts and the integration on Electronic Chart Display and Information Systems (ECDISs). One of the major changes is the decision to replace the problematic star symbology. Recognizing that effective visualizations result in better–informed decisions, we investigate new techniques for the visualization of bathymetric data quality on ECDIS. This is expressed through our countable textures, one with lines and one with dot–clusters, as well as two techniques for improving the data quality integration within ECDIS safety checks. Regarding the former, this paper summarizes the research effort from identifying the deficiencies of star symbology, to conceptualization, development, and evaluation of the countable textures that demonstrated the superiority of the concept compared to ideas previously discussed within the community. Regarding the latter, this paper presents the two techniques under evaluation in collaboration with maritime academies in the US that aim to facilitate the use of data quality information during the execution of the passage.

The usage of Maritime Autonomous Surface Ships in coastal and heavily used maritime environments necessitates advanced navigation systems capable of fully complying with the International Regulations for Preventing Collisions at Sea 1972 and not only open sea encounters. A significant challenge in this domain is enabling autonomous vessels to understand and navigate complex collision avoidance scenarios dictated by Rule 9 Narrow Channels and Rule 10 Traffic Separation Schemes. These rules are not well covered by research and only partial solutions have been proposed. To address this, we propose a ruleset for a system that can blend the traffic situation and geometric constraints extracted from Electronic Navigational Charts in S-57 format. The proposed ruleset extends our previous work on operationalization of COLREGs by introducing spatial features describing the maritime geometries relevant for traffic situations in Narrow Channels and Traffic Separation Schemes. We apply the ruleset to various traffic situations, showing how the inclusion of geometric context improves decision-making by reducing ambiguity and therefore enables the assessment of traffic situations and ship encounters in the vicinity of Narrow Channels and Traffic Separation Schemes. Our work outlines how the integration of spatial features into a rule-based system enables autonomous navigation capabilities of MASS for safe operations and compliance with maritime regulations.