Dear Hydrographer,
Please find attached herewith :
CL 65/2017 :
CALL FOR APPROVAL OF AN IHO RESOLUTION ON THE ELIMINATION OF
OVERLAPPING ENC DATA IN AREAS OF DEMONSTRABLE RISK TO THE SAFETY OF
NAVIGATION
Yours sincerely,
IHO
M.MOLLET
THIS CIRCULAR LETTER REQUIRES YOU TO VOTE
IHO File No. S3/8152 CIRCULAR LETTER 65/2017
22 November 2017
CALL FOR APPROVAL OF AN IHO RESOLUTION ON THE ELIMINATION OF OVERLAPPING
ENC DATA IN AREAS OF DEMONSTRABLE RISK TO THE SAFETY OF NAVIGATION
References:
A. IHO Resolution 1/1997 as amended – WEND Principles;
B. IHO CL 40/2014 dated 26 May – Revision of the Guidelines for the Implementation of the
WEND Principles;
C. IHO Publication S-11 Edition 3.0.0 - Guidance for the Preparation and Maintenance of
International (INT) Chart and ENC Schemes and Catalogue of International Charts and
ENCs;
D. IMO NCSR 4/27/5 dated 21 December 20161 – Report on monitoring of ECDIS issues by the
IHO;
E. IHO CL 51/2017 dated 01 September – Outcome of the Ninth Meeting of the Inter-Regional
Coordination Committee (IRCC9);
F. IHO CL55/2017 dated 31 October - Outcome of the First Meeting of the IHO Council.
Dear Hydrographer,
1. At its 8th meeting, the Inter-Regional Coordination Committee (IRCC) tasked the Worldwide
ENC Database Working Group (WENDWG) to draft an IHO Resolution addressing issues related to
overlapping ENC data. A draft IHO Resolution was discussed and agreed at the 6th meeting of the
WENDWG (WENDWG-6) taking into account existing references (See References A and B) and the
new Edition 3.0.0 of S-11 Part A - Guidance for the Preparation and Maintenance of International
(INT) Chart and ENC Schemes (See Reference C). At their meetings (WENDWG-6 and WENDWG-
7), WENDWG Members agreed on the importance to eliminate all overlapping ENC data that may
cause a significant risk to safety of navigation.
2. This warning on the possible risks of overlapping ENCs on safety of navigation was reinforced
in the IHO status report to the IMO Sub-Committee on Navigation Communications and Search and
Rescue (NCSR) (See Reference D). This report states:
a) In paragraph 16: “…The uncoordinated production of ENCs, resulting in
overlapping data for the same area, and contravening the relevant IHO Resolutions, remains an issue
in less critical areas, notably where the limits of waters of national jurisdiction between neighbouring
countries are not established. Further investigations have confirmed the unpredictable behaviour of
ECDIS operating with Edition 3.4 of the Presentation Library in situations where overlapping data is
used in an ECDIS…”
b) In paragraph 17: “…A mitigation measure has been implemented in Edition 4.0 of
the Presentation Library: where an overlap of two or more cells exists, the ECDIS operating with
Edition 4.0 must only display one cell for the overlapping area and provide a permanent and persisting
1
Also Doc. WENDWG7-05B.
Mapping our Seas, Oceans and Waterways - more important than ever
indication "overlap". At the same time, the issue remains a high priority item on the agenda of the IHO
Working Group on the World-wide ENC Database (WEND) and the relevant Regional Hydrographic
Commissions…”.
3. The IRCC endorsed the WENDWG proposal for a new IHO Resolution addressing issues
related to overlapping ENC data at its 9th meeting (See Reference E, Decision IRCC9/19) and
submitted it for endorsement at the first meeting of the Council (C-1). The Council endorsed
the proposal at C-1 (See Reference F, Decision C1/25) and tasked the IHO Secretariat to
circulate the draft proposed IHO Resolution to IHO Member States, for their consideration and
approval (see Reference F –Action C-1/29).
4. The draft proposed IHO Resolution is provided in Annex A.
5. Member States are requested to take into account the endorsement of the IRCC and the IHO
Council and to consider the adoption of the proposed IHO Resolution by providing their reply on the
Voting Form in Annex B, at their earliest convenience and no later than 30 January 2018.
6. Depending on the outcome of this IHO Circular Letter, the WENDWG will then consider at its
8th meeting planned in March 2018 whether amendments need to be considered for aligning the existing
references A and B to the new IHO Resolution.
On behalf of the Secretary-General
Yours sincerely,
Mustafa IPTES
Director
Annexes:
A. Draft Proposed IHO Resolution
B. Voting Form
2
Annex A to
IHO CL 65/2017
IHO File No. S3/8152
PROPOSED IHO RESOLUTION ON THE ELIMINATION OF OVERLAPPING ENC
DATA IN AREAS OF DEMONSTRABLE RISK TO THE SAFETY OF NAVIGATION
[Proposed] IHO Resolution xx/2017 – Elimination of overlapping ENC data in areas of
demonstrable risk to the safety of navigation
IHO CL xx/2017
Elimination of overlapping ENC data in areas of xx/2017 (as endorsed at IRCC9
demonstrable risk to the safety of navigation and C-1)
1. It has been reported that overlapping ENC data, when used in ECDIS equipment, may lead to
unpredictable behaviour in at least the following cases:
- overlapping data occurring in the same usage band (Navigational Purpose);
- overlapping data occurring in ENC cells in different usage bands (Navigational Purposes) but using
the same compilation scale.
2. Hydrographic Offices, ENC Producers, and Regional Hydrographic Commissions should take
appropriate measures to eliminate all overlapping ENC data, particularly in areas of demonstrable risk
to the safety of navigation.
3. While RENCs and End-User Service Providers may develop certain distribution policies to help
prevent such overlapping data from passing through the ENC distribution chain, the safety of mariners
at sea should not rely on these mechanisms alone, as if they were the primary solution.
4. In addition to the existing procedures related to overlapping ENC data described in:
- IHO Resolution 1/1997 as amended (WEND Principles) and its Annex (Guidance for the
Establishment of ENC Production Boundaries);
- The Guidelines for the Implementation of the WEND Principles, as endorsed by the
11th WEND Committee Meeting in 2008 and amended in 2014;
- S-11 Ed. 3.0.02 - Guidance for the Preparation and Maintenance of International (INT)
Chart and ENC Schemes and Catalogues of INT Charts and ENCs; and
- S-57 - IHO Transfer Standard for Digital Hydrographic Data -, Appendix B.1, Annex A - Use
of the Object Catalogue for ENC (Ed. 4.03.0, June 2014) - clause 2.1.8;
Hydrographic Offices, ENC Producers, and Regional Hydrographic Commissions should seek to:
- Identify overlapping ENC data in all areas of significance to navigational safety within
their areas of production or control;
- Prevent the increase of any such cases; and
- Resolve all of those cases where a demonstrable risk to the safety of navigation exists,
through discussion and negotiation between the relevant ENC producers, as soon as possible,
and at least within one year of any such overlapping ENC data being reported or identified.
5. Notwithstanding the responsibilities of the ENC Producer Member States involved, to take early action
to notify the mariner of possible risks to the safety of navigation, in any case where the elimination of
overlapping ENC data cannot be resolved and its continued existence presents a demonstrable risk to
2
To be replaced by Ed. 3.1.0 if adopted by IHO Member States (IHO CL 59/2017 refers).
3
To be replaced by Ed. 4.1.0 if adopted by IHO Member States (IHO CL 61/2017 refers).
the safety of navigation, the procedures described in section 1.7 of the Guidelines for the
Implementation of the WEND Principles should be applied. The timescale to resolve should be within
one year of the matter coming to the attention of the ENC Producer Member States involved. Section
1.7 states:
"1.7. The S-57 Standard allows minimal overlap of ENC data within usage bands. ECDIS
systems will operate unpredictably in areas where significant overlapping ENC coverage is
present, raising a potential navigational risk to end-users. Where overlapping coverage exists
the Producer Member States should recognize their responsibility and take the necessary steps
to resolve the situation. To ensure that overlapping ENC data coverage is resolved to the
satisfaction of the Regional Hydrographic Commission (RHC), the following procedures
should be undertaken in sequence until there is satisfactory resolution:
1.7.1 The RHC will identify and assess ENC coverage within their area of
responsibility and highlight those areas where there are navigationally significant
differences between the overlapping ENCs. The assessment of what may be
navigationally significant should be guided by the best practices in this regard,
acknowledged and approved by the IRCC. The RHC may seek the assistance of a
Regional ENC Coordination Centre (RENC) to assist in development of this assessment
and should take a proactive approach with the ENC Producer Member States, to resolve
overlap issues within the region.
1.7.2 The RHC will keep the IRCC Chair and the IHO Secretariat informed, through
the annual reporting process, about overlaps in ENC coverage, their associated risks
and related action(s) taken by the coastal States and/or the Producer Member State.
Appropriate action by the IHO Secretariat should be initiated to inform the International
Maritime Organization of the situation with details of the desired actions to be taken by
the Government(s) of the involved coastal State(s) and the risks associated with inaction.
1.7.3 Where urgent action is required to alert mariners to navigationally significant
overlap issues then the RHC, through the concerned Producer Member States, should
initiate promulgation of appropriate warnings directly with the regional NAVAREA
coordinator and other local navigational warning protocols, while keeping the IRCC
Chair and IHO Secretariat informed."
A-2
Annex B to
IHO CL 65/2017
IHO File No. S3/8152
PROPOSED IHO RESOLUTION ON THE ELIMINATION OF OVERLAPPING
ENC DATA IN AREAS OF DEMONSTRABLE RISK TO THE SAFETY OF
NAVIGATION
Voting Form
(to be returned to the IHO Secretariat by 30 January 2018)
E-mail:
[email protected] - Fax: +377 93 10 81 40
Note: The boxes will expand as you type your answers.
Member State:
Contact:
E-mail:
Do you approve the adoption of the new IHO Resolution as provided in Annex A (tick the appropriate
box)?
YES NO
If you answer ‘NO’, please explain your reasons in the comment section below.
Comments:
Signature :
Date :
B-1