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The documents you find on this wiki site are "works in progress", they are in the process of being drafted and do not represent official statements either of the IHO or of the member states represented by the participants in this group.
The official IHO Downloads page is the repository for completed standards which are approved by member states.
The primary purpose of S-121 is to allow States to communicate official digital representations of their maritime limits and boundaries to the public and international community. The standard is designed to be acceptable as a method for States to fulfill their deposit obligations under the Convention. S-121 is established to depict, describe and communicate national maritime limit or boundary positions without prejudice to maritime boundary disputes. S-121 does not seek to resolve disputes between States: Where disputes exist, the standard will facilitate visibility of those disputes by allowing each party to publish its own position. The S-121 secondary purpose is to provide a flexible and expandable framework able to support other maritime delimitation requirements such as defining Joint Development Areas, or any other management areas.
The vision for this standard is to leverage the capabilities of the ISO-19152 Land Administration Domain Model. ISO-19152 supports the legal description of associated rights, restriction and responsibilities along with providing proper referencing through sourcing and versioning. This additional capability aligns the standard with legal practices of trace-ability. The use of the ISO-19152 standard leverages the significant community investment made in land administration, with which the management of maritime boundaries and limits has much in common. The use of ISO-19152 provides a foundation to extend S-121 into the management of other regulated boundaries, such as marine reserves and fisheries. Alignment with the land domain model will facilitate consistent administration of the littoral zone for those states that adopt S-121 for their marine spaces and ISO-19152 for their land jurisdiction.
The S-121 standard is designed to provide a flexible management and communication solution that can support any type of MLBs for the broadest range of users including the Owner State, other States, the international community, government organizations, private industry, academic institutions, and the general public. By construction, the standard also remains compatible with S-101 (Electronic Nautical Chart Product Specification) to allow for the depiction of the MLBs information encoded by the standard to be displayed in electronic navigation charts.
The S-121 takes a practical step toward achieving the vision of S-100 as it was established: to expend the user base and better accommodate the requirements of our digital world. By building on ISO-19152, the S-121 framework provides the capacity to more efficiently and consistently administer across the land and maritime domains. It is essential that we evolve current practices to provide a foundation for sustainable administration of the world’s blue economy. Use of the S-121 standard will reduce costs of enforcement and compliance, and will support the extension of the digital economy into the offshore.
Our planet’s oceans are subdivided by international and national laws into many zones. At the highest level, these zones define where States exercise sovereignty and sovereign rights, and identify areas beyond national jurisdictions that fall under international jurisdiction.
Maritime Limits and Boundaries (MLBs) are the constructs used to delineate maritime zones and forms the legal foundation of the marine domain. These maritime zones are established in law by their geographic limits .
To effectively distribute MLBs for the due publicity obligations under the Law of the Sea Convention and operational purposes, there needs to be a standard framework which ensures compatibility between users and encodes the legal character of the MLBs.
The Law of the Sea Convention says that: “Coastal States, … are required to deposit with the Secretary-General of the United Nations charts showing straight baselines and archipelagic baselines as well as the outer limits of the territorial sea, the exclusive economic zone and the continental shelf; alternatively, the lists of geographical coordinates of points, specifying the geodetic datum, may be substituted. Coastal States are also required to give due publicity to all these charts and lists of geographical coordinates.”
The S-121 standard needs to provide a set of feature types and an attribute structure that allows for the representation of the legal aspects of MLBs. These features can be included within “charts” or can be represented separately for deposition as “lists of geographical coordinates of points”.
The deposition of “charts” may be printed paper charts or images of charts. Specialized certified equipment is required for reading IHO S-57 or S-101 Electronic Nautical Charts (ENCs) and these charts are not directly readable without this specialized equipment. However, ENCs are read by mariners in a navigational context and when Maritime Limits or Boundaries are shown on ENCs they need to be derived directly from the features and attributes that are included in a deposit to the UN.
The deposition of “lists of geographical coordinates of points” needs to be a complete set of feature types and attributes that fully describe the MLBs including related attributes such as legal aspects, source and the parties involved. In order for these features, attributes and coordinates to be read by the UN Commission they will need to be encoded in a human readable form that can be presented to a dispute resolution body and understood without specialized knowledge.
The International Hydrographic Organisation (IHO) has defined the S-100 Universal Hydrographic Data Model as a versatile standard framework aligned with the International Organization for Standardization (ISO) 19100 Geographic Information / Geomatics series of standards. The IHO S-100 standard aims to support a wide range of users by developing digital products and transfer standards for the marine community beyond the core hydrographic applications of the IHO. This includes support for MLBs.
The Maritime Limits and Boundaries standard - S-121 represents an essential extension of S-100 for the administration of the marine domain. S-121 establishes a framework for communicating in a digital form the geographic extents of marine areas and the associated rights and restrictions that apply to them. The framework has been developed to rigorously apply the provisions of the United Nations Convention of the Law of the Sea (UNCLOS), while allowing sufficient flexibility to accommodate the diverse implementations of the Convention by States under domestic laws.
The primary purpose of S-121 is to allow States to communicate official digital representations of their maritime limits and boundaries to the public and international community. The standard is designed to be acceptable as a method for States to fulfil their deposit obligations under the Convention.
S-121 is established to depict, describe and communicate national maritime limit or boundary positions without prejudice to maritime boundary disputes. S-121 does not seek to resolve disputes between States: Where disputes exist, the standard will facilitate visibility of those disputes by allowing each party to publish its own position.
The S-121 secondary purpose is to provide a flexible and expandable framework able to support other maritime delimitation requirements such as defining Joint Development Areas or any other management areas.
The S-121 standard leverages the capabilities of the ISO 19152 Land Administration Domain Model. ISO 19152 supports the description of associated rights, restriction and responsibilities along with providing proper referencing through sourcing and versioning. This capability aligns the standard with the practices of traceability. The use of ISO 19152 provides a foundation to extend S-121 into the management of other regulated boundaries, such as marine reserves and fisheries. Alignment with the land domain model will facilitate consistent administration of the littoral zone for those states that adopt S-121 for their marine spaces and ISO 19152 for their land jurisdiction.
By compliance with S-100, the S-121 standard remains compatible with S-101 (Electronic Nautical Chart Product Specification) to allow for the depiction of the MLB information encoded by the standard to be displayed in electronic navigation charts. That is, a feature object such as the Territorial Sea zone or the Outer Limit of the Territorial Sea can be imported directly into S-101 and become feature objects in an Electronic Nautical Chart. In the S-121 environment these objects would carry additional attribution that allows the description of legal rights restrictions and responsibilities and support versioning and source referencing to maintain traceability.
The S-121 takes a practical step toward achieving the vision of S-100 as it was established to expend the user base. By building on ISO 19152, the S-121 framework provides the capacity to more efficiently and consistently administer across the land and maritime domains. Use of the S-121 standard will reduce costs of enforcement and compliance, and will support the extension of the digital economy into the offshore.
The S-121 standard consists of a product specification compliant with the relevant International Organization for Standardization (ISO) and International Hydrographic Organization (IHO) standards. The product specification for Maritime Limits and Boundaries is based directly on IHO S-100. The data model makes use of S-100 geometry and S-100 feature and attribute structure. It defines several new feature types and attributes types. The approach used is the creation of several information object types that behave as attributes to the features by reference. This allows relations to be established between the information objects permitting a complete description of a management environment including reference to shared versioned parties, rights, restrictions and responsibilities, and sources.
Built on top of the data model structuring the information, there is a need for several encodings (exchange format) to support key usages. (1) MLB objects may be used as a source for some elements of navigation products such as ENC and would follow an S-101 encoding. (2) A separate encoding would be needed for a stand-alone MLB product or the use of MLB objects in a Marine Cadaster. (3) This standard also establishes a structured text record oriented exchange format that is both readable and comprehensive by both the human eye and a computer. This exchange format is designed to support the description of legal aspects of the MLB objects in a manner so that they can easily be presented in an official venue. This data needs to look similar to the current text in treaties and laws.
MLB objects have four major components: 1. The party component which defines the different actors and the role associated with an object. 2. The geospatial component which defines the location and type of the object. 3. The legal component, which supports the description of the associated jurisdictions, and rights, restrictions and responsibilities associated with objects. 4. The source component, which references administrative or spatial sources such as treaties, legal documents, charts and other sources.
In addition to these components the S-121 standard provides a versioning capability. Historical tracking (versioning) of an object’s evolution is required in legal or political disputes to justify the representation of a particular MLB object.
This document is structured as a Data Product Specification as defined in the ISO standard ISO 19131 Geographic Information – Data Product Specifications and IHO S-100 Part 11. One general product specification is defined, with several conformance classes. These conformance classes invoke different parts of the product specification allowing one to address different needs.
Associated with the S-121 Product Specification document are several support documents. These are:
- An Encoding Document that describes the approach to encoding S-121 data including the definition of a record oriented text format that can be easily read by humans and which supports deposition with the UN and legal review.
- A Data Classification and Encoding Guide (DCEG) document that describes all of the feature objects and attributes defined for Maritime Limits and Boundaries. This includes a complete Feature Catalogue giving the definition of each feature, attribute, code list and listed value.
- A Derivation of Classes support document. The Product Specification document contains the Application Schema data model, however the classes used in this data model derive from IHO S-100, ISO 19152 LADM (Land Administrative Domain Model) and other ISO standards. The Derivation of Classes document details the relationships such as inheritance and realization between the S-121 data model and the source classes from these other standards.
All relevant documentation can be found in the Documentation tab.
- Product Specifications - Model in Enterprise Architect and HTML format - Class Derivation - Other relevant documentation