Abstract
1. INTRODUCTION
The International Hydrographic Organization (IHO), with the purpose of unifying the use of digital cartography and the exchange of hydrographic data, published the S-57 Digital Hydrographic Data Transfer standard for the production of electronic nautical cartography (IHO, 2000), which allows paper nautical chart data to be transferred digitally in a standardized form from the elements of an Electronic Navigation Chart (ENC) (Zou, Wang, & Wang, 2012).
The ENC is defined as: A standardized database in terms of content, structure, and format, published by Hydrographic Services under the authority of a government, for use in an electronic chart information display system (ECDIS). ECDIS is adopted by the International Maritime Organization (IMO) as part of the requirement on board ships which must carry the official ENCs for safe navigation (IMO, 2006).
Therefore, the International Hydrographic Organization coordinates world hydrographic activity, with the support of the Regional Hydrographic Commissions (RHC), which are 16 geographical divisions, made up of IHO member states with common interest, urging countries to contribute and unite efforts in planning, execution of hydrographic surveys and production of cartography. However, despite the recommendations of the IHO, it is not guaranteed that countries will fully follow or abide by the regulations.
2. BACKGROUND
As of the fifth meeting of the Hydrographic Commission of the Caribbean Sea and MesoAmerica (MACHC) in 2002, several hydrographers from this region discussed the first guidelines for the creation of electronic navigation charts for the region, using as a basis the existing international paper nautical chart scheme (CHRIS, 2003). It is important to bear in mind that the cartography planes are defined by each State in a sovereign way, in which the charts and scales necessary to cover a territory were obtained. However, there are “International Paper Chart Schemes”, which are established for the different Regions. These schemes define the areas covered, the chart scales and the countries responsible for their production. This work is carried out at the regional level but coordinated by the IHO working groups, based on specifications is- sued by the same Organization, contained in publications such as S-11, for medium and small scales in order to meet the needs of international maritime traffic safety.
In subsequent meetings, member countries that make up the MACHC, such as Brazil, Colombia, Cuba, France, Mexico, Netherlands, Suriname, United Kingdom, United States of America and Venezuela, have reported the progress of their cartographic production within the framework national and international, both paper and electronic. In order to achieve adequate coverage of the ENCs, since the twelfth meeting of the MACHC in 2011, the production of official electronic charts in the region has been encouraged and the availability of the data used in their construction has been promoted through the Committees; Electronic Chart (ECC) and International Chart (ICC), currently known as the MICC, (MACHC Integrated Chart Committee, 2011).
3. PROBLEMS IN ENC COVERAGE
The production of ENCs in the Caribbean has so far been carried out using the schemes that already existed for paper charts, which, although it was the easiest to implement, has generated several problems. The most important is that many cells (ENCs) have a significant overlap area, which although it was advisable for paper charts by facilitating the mariner to move from one chart to another during their route, generates several problems in the ENCs, when cells are presented with areas of irregular overlapping information, poor horizontal consistency and lack of information or gaps in the continuity of the cells, which prevents obtaining a uniform coverage (La Pira, 2010). The foregoing, mainly due to the fact that in the same ENC there are areas overlapped by several nautical paper charts at different scales, which, when used in the creation of a single cell or electronic chart, generate the aforementioned inconsistencies.
Currently, electronic nautical cartography has been replacing paper charts, due to the work advantages offered by the use of ECDIS as a system, by integrating ship sensors and navigation aids, such as: log, gyrocompass, GPS, ENCs , RADAR, buoys, lighthouses, among others (Salgado Don, 2015; Śniegocki & Wieliki, 2010), which allows interrogation, visualization and filtering of the information according to the navigation route or maneuver that the navigator is developing, thereby improving their safety.
According to the Nautical Cartography Working Group of IHO, the use of paper charts has declined from 2008 to 2018 by around fifty percent worldwide, the production of electronic navigation charts has increased (NCWG, 2020). As evidence between 2014 and 2016, based on the production of 40 member countries of the International Center for ENC (IC-ENC) the growth was from 4,916 to 7,330 ENCs. One of the reasons for this increase in ENC production is the IMO regulations that make the use of ECDIS mandatory from 2012 and progressively until 2018 according to the tonnage of the vessels. In the IC-ENC report, for 2016 the increase in the production of electronic charts in the following countries stands out: Ecuador 71.4%, Venezuela 127.8%, Egypt 23.5%, Pakistan 16.7% and Chile 15%. (IC-ENC, 2017).
The reports of the working groups that make up the RHCs are essential for the monitoring of the cartographic production carried out by the working group on the world database of electronic navigation charts. (WENDWG). This group has recommended increasing the execution of the schemes for the nautical purpose or usage bands from 1 to 3, corresponding to the purposes of Oceanic, General and Coastal navigation managed in the scale ranges <1:1.499.999, 1:350.000 – 1:1.499 999 y 1:90.000 – 1:349.999 respectively, (IHO-IRCC9, 2017) This cartographic production should take into account the revisions of the IHO Strategic Plan, the IHO resolution to eliminate overlapping ENCs and the recommendations of the Regional Centers for Electronic Navigation Charts (RENC), on the importance of eliminating the overlap of the data.
Based on the status and progress in the worldwide electronic cartographic production described in the previous paragraphs; not having a regional ENC scheme adopted by the RHC has shown inconsistent coverage due to the various designs, difference between the handling of scales, data, and ENC coverage affecting maritime safety due to the irregularity in the presentation of the data. According to the analysis and results obtained through surveys, the strengths and weaknesses represented in the existing coverage were socialized before the annual meetings of the MACHC and the need to strengthen the RHC was apparent, therefore, through the Assembly it is created the Sub-Working Group for Regional Schemes of standardized ENCs, endorsed at the MACHC 20th meeting.
From the meeting 20th to June 2021 there are investigations involving the producing countries and leaders of the US, UK and CO subgroups who are investigating possibilities and options for the region’s scheme, starting with the Oceanic usage band.
There are countries that are re – schematizing their charts to solve problems, as an example the USA (https://nauticalcharts.noaa.gov/publications/docs/ENC-Transformation.pdf), however it is done independently and not as part of a RHC scheme.
4. ENC PRODUCTION BY THE HYDROGRAPHIC SERVICES IN THE MACHC
In the case of the countries that make up the Caribbean Sea, there is a difference, because most do not have a hydrographic office and the nautical publications of these countries have been assumed by other nations, such as the United Kingdom, United States, Holland and France. This is especially true for the United States, who at the beginning of the 20th century made a great effort to carry out surveys and produce nautical charts in the Caribbean Sea and on the coast of America in the Pacific Ocean. Through the National Oceanic and Atmospheric Administration (NOAA) in the 90’s, it began the production of its electronic charts from the digitization of paper charts and is currently developing a strategy to transform nautical cartography. in the National Cartography Plan, in order to solve problems in its products, such as: duplication of information, elimination of cells with irregular shape compiled in 130 scales, among others (Office of Coast Survey, 2017).
1. ANALYSIS OF CURRENT ELECTRONIC CHART SCHEMES
To analyze the design of the regional cartographic schemes, information was pulled from the web portals of the Regional Hydrographic Commissions, the Value-Added Resellers (VARs) and the IHO catalog (Figure 1), whose information is provided by RENCs, Member States and distribution agencies.
For the analysis of the current ENC schemes, a series of activities were carried out, which are listed below. The first two activities involved analysis of the Regional Hydrographic Commissions, based on the information available on the IHO portal:
(i) The ENCs produced by the countries that make up each RHC were reviewed, examining the following aspects:
– The design of the ENC scheme: to identify, first, if there is a scheme approved and adopted by the countries of the region, which allows greater uniformity in the representation and consistency of the data; and second if the ENC design is completely adjacent or, on the contrary, information is lacking in the same navigation purpose (overlap and / or gaps).
– Metadata: allows for identification of the scales used in production and determination if they follow those recommended by the IHO standards, the cartographic production capacity of the
(ii) Information was recorded on the aspects examined by each country of the RHC, taking into account metadata such as the producer country, navigation purpose, scale for each polygon that represents the ENC data coverage, as detailed in the Table 1.
Table 1 Record of aspects examined in the countries that make up the Regional Hyd rographic Commissions,
taking into account metadata of the ENC coverage
In the Table 1 the distribution of the designs in each one of the RHCs is appreciated, where the majority use the three designs, finding cases in the countries that use combined designs; For the MACHC Commission, it is the Equivalent to paper charts and Exclusive for ENC, in the purpose of coastal navigation.
The following activities were carried out exclusively for the ENCs that map the Caribbean Sea, considering the complexity in the production.
(iii) The cartographic coverage for each related port or area of interest was reviewed, identifying the products for navigation purposes and scales established by producers.
(iv) The horizontal consistency of the data was examined, filtering the ENCs by navigation purpose from the portal of the MICC committee of the MACHC, which contains the vector product, allowing the analysis of all objects according to the type of geometry, for:
Polygon: Depth Areas, Special Areas, Magnetic Variation, among others.
Line: Series of contours defined for the chart according to the scale or purpose according to the specifications, unify series for purposes taking into account the configuration of the safety contour between the ECDIS parameters; cabling, coastline, among others.
Point: Sounding, hazards, navigational aids, among other point objects that display value is applied to them in the ECDIS through the minimum scale attribute (SCAMIN).
(v) The international paper chart scheme for the region was compared with the coverage of the ENCs published on the MICC committee portal, identifying whether the INT scheme was adopted by the countries for the production of electronic cartography.
(vi) The results of the analysis were shared with the RHCs, RENCs and working groups of the IHO related to the subject, in order to receive suggestions and comments to substantiate the proposal to standardize regional schemes through a re-schematization to unify navigation purposes.
(vii) A questionnaire was formulated and applied to the member countries of the RHCs and the RENCs, to provide feedback and complement the information analyzed, in order to know if the RHC has established standardized schemes in the region that the countries have approved and adopted, or on the contrary if the countries agree to re-schematize for navigation purposes that cover international waters, allowing to have a uniform coverage.
2. SURVEYS TO HYDROGRAPHIC SERVICES
This section develops the analysis of the results of the questionnaire to the member states of the Regional Center for electronic navigation charts.
In general, the analysis indicates that, close to three decades after having published the standard for electronic charts, the producing countries worldwide continue to work in the search for strategies and mechanisms for the continuous improvement of ENCs, in terms of quality, precision and updating.
During the socialization, in technical meetings of the electronic cartography working groups and IHO commissions, criticism and positive comments were received, which show the applicability and the benefit of being able to carry out the objective of Regional Schemes. The president of the International Center for ENCs (IC-ENC), asked if there are similar efforts in his region to that of the present work, giving the result that countries are working independently, due to challenges of sharing data between nations.
Consequently, the idea of presenting an academic questionnaire for IC-ENC members was raised, a commitment that was endorsed by them and supported by IC-ENC in accordance with action 5 of technical report TC03 / 19 (IC-ENC, 2018), in order to obtain more information about the commissions.
The most important aspects of the questionnaire are highlighted below.:
(i) During the third IC-ENC technical conference of 2018, an action was agreed between the participating members, to answer a questionnaire for academic purposes for research.
(ii) IC-ENC sent the survey to 44 member states, of which only 9 responded, in a period of five months. That is, 20.25%, which represents a difficulty in making decisions based on this instrument.
(iii) Five countries do not have regular plans to maintain horizontal consistency between ENCs with border countries.
(iv) The countries agree that the RHCs establish standardized regional schemes for Oceanic, General and Coastal purposes, however, the USA indicates that it would be a difficult task for the hydrographic offices. The difficulty lies in the origin of the data they used to create the ENCs, which leads to handling different levels of compilation scale in current ENCs, fearing that changing the compilation scales could create an ENC with poor data quality.
(v) Regarding re-schematization, a negative response was received by one of the countries stating its commission works in a coordinated manner and, it does not consider it necessary to carry out a complete restructuring in terms of overlaps and gaps. The few remaining cases must be resolved (locally adjusted or modified) among the NCD producers involved; this is encouraged by the NSICWWG.
(vi) Unify the compilation scale by navigation purpose, bearing in mind that the standards do not define scales for each usage band, on the contrary, a wide range of scales is recommended. Set a fixed minimum and maximum, and fixed defined values to use between this minimum and maximum for each band. With respect to this point, the Eastern Atlantic and Mediterranean regions already have these purposes standardized. No argument was received against this procedure.
(vii)Three of the nine countries consider the prior review of ENCs by the RHC to be beneficial, they are countries that are strengthening capacities for the production of their ENCs, one of the countries is replacing the ENCs generated by the UKHO.
3. EVALUATION OF THE DIFFERENT DESIGNS OF CURRENT ENCS SCHEMES
With the result of the questionnaire to the Member States, the information obtained during the analysis of the scheme designs in the RHCs is corroborated. (Table 1), of not having standardized regional schemes. In the Table 2, advantages and disadvantages of the diversity of designs of the current schemes are defined. The three evaluated designs are:
Design equivalent to a paper chart. It refers to when the ENC scheme preserves as a pattern the coordinates and scales of a scheme for paper nautical charts, and even the areas of overlap. On paper charts at the same scale, it is necessary that these areas exist to maintain continuity of data during change of charts.
Grid. It is a design using a network of lattices that show parallels of latitude and meridians of longitude, in a uniformly spaced manner.
ENC Exclusive Schematic Design. It corresponds to the electronic chart scheme based on the recommendations of the WEND principles, specifically in not duplicating data and avoiding gaps between cells for the same purpose, optimizing the information compiled from the different cartographic sources and generating a cell that provides the information according to the purpose. navigation.
4. WEAKNESSES AND STRENGTHS
The results corresponding to activities such as a review of designs, metadata, port coverage and consistency of electronic navigation charting schemes, classified into strengths and weaknesses as follows:
weaknesses
(i) Difference in the information published between the portals of the RHCs, IHO and the VARs commercialization catalog.
For the MACHC region, a specific case is presented, where there are differences between the cells reported in the portals of the MICC committee and the MACHC committee with respect to the ENCs that are available in the UKHO VAR catalog.
Table 2 : Advantages and Disadvantages of severals ENC Scheme Designs
Regarding this disparity, the IHO has coordinated with the Hydrographic Service of Korea on the development of a portal where the ENC coverage and complementary information of all the Regional Hydrographic Commissions are centralized and visualized, establishing itself as the only place to obtain the information. The pilot project was presented during 2018 at the meetings of the WEND and NCWG nautical cartography working groups.
(ii) Disparity in the design of the existing schemes in the hydrographic offices, given that there is no standardized pattern for the production of ENCs in the RHCs, which indicates that most of the producing countries are doing it independently, evidenced by a lack of uniform coverage. For each RHC there is a diversity of designs (Figure 2), such as the Grid system, the equivalents to paper charts, adjacent rectangular cells, and the combination of systems by the same producer.
(iii) Regarding the analysis of the ENC metadata in the RHCs, the information on the compilation scale is considered a weakness. This is due to the need to know the varied use of scales for navigation purposes in the region, which represents the application of the attribute of minimum visualization difficulty to the objects; does not guarantee a complete visualization of the coverage through ECDIS systems; and shows non-compliance with the series of scales recommended by the IHOI specifications.
(iv)In general, in all the RHCs, the dependence on the cartographic production of other countries is evident.
In the framework of uniform coverage available for the region of the MACHC, incomplete coverage is appreciated, due to the inequality in the cartographic capacities of the countries that make up the region, however, some areas are covered by cells produced by other countries. One case is that of the Cayman Islands, (Figure 3) ENCs from these islands are produced by NOAA for Oceanic and General purposes and by the UK Hydrographic Office for Approach and Port purposes, on the 1: 2 160 000, 1: 1 200 000, 1: 45 000 and 1: 8 000 scales respectively.
(v) Most of the countries did not adopt the international paper chart scheme for each region during production of ENCs. A specific case, the INT Region B MACHC chart scheme was analyzed, in which Colombia and Venezuela partially used the international chart scheme:
Venezuela and Colombia neighboring countries adopted the INT paper chart scheme, however, the ENC coverage for the General purpose is not continuous; in the area there is a cell captured by the UK Office, it does not use the limits of the INT scheme of the region.
As shown in Figure 4
In the coastal scales, the cells present inconsistencies with respect to the adjacent depth area, where the Venezuela cell represents a depth area of 20m to 200m, and the Colombia cell shows the area with a depth range of 50m to 100m. This is the cause of the inconsistent display that is shown in the ECDIS, under certain settings, the two areas in different shades of blue.
Due to the differences between the medium-scale INT chart scheme and the Coastal use band 3 ENC coverage, in this subregion, it is important to assess whether there is adequate ENC coverage for this purpose due to the density of maritime traffic.
In addition, incomplete coverage, whether in a specific region or in bordering situations, is also due to the varied handling of the compilation and display scales for a navigation purpose, (Figure 5) generating uncertainty to the end user and unpredictable behavior of ECDIS.
Strengths
Currently, other countries like USA, are implementing strategies for their products such as raster charts, ENCs and paper, re-schematizing their cartographic production plans independently in a Grid system.
The dependence of cartographic production in other countries is shown as a strength, due to the increasing coverage of ports, especially with the purposes of navigation in the Bay and Approach, contributing to the security and economy of the region.
There is a recognized need by the member states of the MACHC region to harmonize ENC coverage for Coastal, General and Oceanic navigation purposes.
Finally, there is strength in the willingness of the countries to seek strategies to acquire capacities and evaluate their production, in a regional manner, considering the impacts faced by the end user (ECDIS) regarding the management of several scales and designs of ENC schemes for purposes of navigation.
5. WORK IN PROGRESS MRES WORK SUBGROUP (ENC MACHC REGIONAL SCHEME)
Faced with the large task of strengthening the management of the MACHC regarding the coverage of ENCs, evidence of the weaknesses and strengths found on the ENC designs in the regions was presented during the 20th meeting of the MACHC 2019, with special emphasis on the commission. As an initial result of research for academic purposes, the option of Regional ENC Schemes was proposed to be approved by the commission in order to unify scales, scheme origin and cell sizes for Oceanic, General and Coastal navigation purposes. (MACHC, 2019)
Standardization, in this contect, refers to maintaining uniformity and consistency for the purpose of maritime safety. This requires ENC producer countries to take the right course when thinking about providing quality and safety to the end user. As a result, hydrographic offices must address the need to redefine their ENCs to achieve this objective.
The design of the adjustment scheme was socialized, presenting a solution for the study area, proposing a greater coverage with fewer cells based on the ENC coverage and the INT scheme of paper charts; always seeking to maintain contiguous, adjacent cells; and giving coverage to the ports and geographical features. Finally, it was deemed necessary to make adjustments in the Coastal scale before it is discarded because the project line focuses on harmonizing and standardizing, which would leave the solution centrally and temporarily for the MACHC regardless of the current position of the International Hydrographic Organization in achieving consistent integrity with other RHCs.
Therefore, as part of the fruitful discussion on the research, the Assembly approved the creation of the MICC – MRES (MACHC Regional ENC Scheme) working subgroup during the MACHC 20th Regional Hydrographic Conference, led by Mexico and Colombia.
The first action of MICC-MRES was the analysis of the proposal made by Colombia at the MACHC 20th Regional Hydrographic Conference of a Regional Scheme by means of a questionnaire that would capture the point of view and considerations of each country on the convenience, feasibility and the acceptability of having a regional scheme, taking into account the complexity of the needs that are required to change the scheme (technical, professional, financial resources, time, among others).
According to the feedback carried out (MACHC, 2020), opinions were divided between five countries; some supported a new scheme with the Grid system while others supported the need to ad- just only the current ENCs, making the size more flexible in sectors where there are gaps under the idea of harmonizing in terms of compilation scale with consistent application rules such as the use of SCAMIN, to ensure visualization for the ECDIS user.
The subgroup decided to start by developing options for the minor bands (Oceanic and General) and assigned actions to develop a common proposal for Grid schemes. The goal is for the producing countries to reach an agreement and start with the implementation and redesign before facing the challenge of the S-101 standard.
The United States supports the proposal to opt for regional schemes, therefore, it has provided the scheme prepared for its country (Nyberg, J. et al, 2020) as a reference for the investigation process (Figure 6). However, the United Kingdom continues to explore options in order to adjust the better coverage of your production globally.
Through statistical analysis based on the size of current ENCs in the MACHC, the MRES subgroup has made a proposal for a Grid scheme for the Oceanic usage band (Figure 7), in order to jointly discuss with the Member States aspects such as origin of the Grid, cell sizes for navigation purposes and the definition of scales for harmonized production at a regional level with global influence (Figure 8).
5. DISCUSSION
The proposal to adjust the scheme is not a regular Grid system, it is a proposal to unify sizes based on the current coverage and sizes of INT Paper charts, in order to reduce the number of cells to maintain. Considering the differences between the production capacities in the countries of the region, an alternative was proposed to reduce the impact on production.
The design of the proposed regular Grid system would be ideal for a seamless global scheme; therefore, it is necessary for the IHO to approve the scales, the sizes for the cells for navigation purposes and the origin of the grid established by the Subgroup of MRES work in order to avoid transferring the problems of the past. It must be taken into account that some nations have already migrated a gridded ENC scheme, independently presenting a difference between the sizes of the ENCs.
Gridded ENCs can support future solutions for automated paper chart production from ENCs. Some countries like Australia, Germany, Japan, Korea have partially migrated their ENCs to regular grid designs (USCHC, 2021); for the United States, NOAA is currently transforming their ENC scheme.
6. RECOMMENDATIONS
- The working subgroup should conduct further research and discussion on a possible ENC grid for the MACHC. It would be useful to know the opinions of more of the member states, and to get producers to agree on the uniform grid that allows an optimal and comprehensive schema.
- Establish ENC schemes at the level of standardized RHCs for the purposes of Oceanic, General and Coastal navigation that are approved and adopted by the region in order to guarantee the end user a consistent coverage, avoiding continuing the production of ENCs independently.
- When designing the cell scheme, overlaps and gaps should be avoided for coverage in the same navigation purpose, which allows greater consistency between products, increases the confidence of navigators, optimizing the performance and use of ECDIS.
- Every port must be mapped regardless of the size or activity it carries out for the sake of security.
- Unify, among the producing countries of the region, the information corresponding to the range of compilation scales for navigation purposes recommended by IHO Circular 047 of 2004, in order to facilitate the application of the minimum display scale attribute (SCAMIN) in subsequent ENCs and ensure continuous mapping via ECDIS (IHO, 2004).
- In order to provide uniform and quality coverage to the end user, it is recommended that neighboring countries establish agreements or memoranda of understanding between producing countries in order to authorize shared publication of data.
- Carrying out bathymetric surveys complying with IHO standards is one of the fundamental aspects to have the adequate information that must be represented in the ENCs.
7. CONCLUSIONS
The IHO has long suggested a gridded approach to an ENC scheme, as typified by its many publications on the subject. During an IHO meeting in Singapore, this uniform grid approach was formally proposed to the hydrography community. (HSSC, 2009). However, after a decade there is still a debate on the problem of overlaps and gaps.
This research and analysis concludes that the proposal of a new Grid scheme will avoid overlaps and gaps, which mainly benefits the ECDIS user by having a uniform display increasing maritime safety.
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9. AUTHORS BIOGRAPHIES