S-100 IHO Universal hydrographic data model
S-100 – IHO Hydrographic Geospatial Standard for Marine Data and Information comprises twelve related parts that give the user the appropriate tools and framework to develop and maintain hydrographical related data, products and registers. These standards specify, for hydrographical and related information, methods and tools for data management, processing, analysing, accessing, presenting and transferring such data in digital/electronic form between different users, systems and locations. By following this set of geo-spatial hydrographical standards users will be able to build constituent parts of an S-100 compliant product specification.
S-100 conforms as far as is reasonably possible to the ISO TC 211 series of geographic information standards, and where necessary has been tailored to suit hydrographical requirements.
S-100 details the standard to be used for the exchange of hydrographical and related geospatial data between national hydrographical offices as well as between other organisations and for its distribution to manufacturers, mariners and other data users.
S-100 comprises multiple parts that profile standards developed by the ISO Technical Committee 211. ISO TC 211 is responsible for the ISO series of standards for geographic information. The objective is that, together, the standards will form a framework for the development of sector specific applications that use geographic information. S-100 is an example of such an application.
This standard specifies the procedures to be followed for:
- establishing and maintaining registers of hydrographical and related information;
- creating product specifications, feature catalogues and a definition of the general feature model;
- using spatial, imagery and gridded data, and metadata specifically aimed at fulfilling hydrographical requirements.
S-100 covers a wide range of activities with the hope of harmonizing them for hydrographical data and ensuring interoperability. The profiles define a subset of requirements that are specific for hydrographical data, but ensure interoperability with other data sources. Each profile would have its own implementation benefits, for example, the metadata profile defines a metadata schema for hydrographical data and extends the ISO 19115 for this application to ensure that all the aspects of hydrographical data are covered in the profile.
S-100 was developed to align and exploit ISO/TC 211 standards to support a variety of data formats, products and customers. The data model will allow the development of new applications that leverage the new technologies and reaches beyond the traditional scope of hydrographical applications. S-100 encapsulates the use of best practice methods and procedures by including guidelines on implementing efficient production methods, optimizing the quality of products and services, and enabling interoperability through common interfaces.
S-100 specifies a framework of components that can be used by interested communities to develop their own maritime geo-spatial products and services. S-100 consists of eleven profiles of ISO/TC 211 standards:
- Conceptual Schema Language
The first part of S-100 specifies a CSL and basic types that shall be used within the IHO community. The CSL is defined as a combination of UML and a set of basic data type definitions for specification of geographic information. Guidelines on the use of UML to create standardized geographic information and service models are also provided. Basic knowledge of the Object Management Group (OMG) UML is required to understand and implement the CSL profile.
- Management of IHO Geospatial Information Registries
The management of IHO geo-spatial information registries profile specifies the procedures that shall be followed when maintaining and publishing registers of unique, unambiguous and permanent identifiers assigned to items of geographic, hydrographical and metadata information. The roles and responsibilities for management of a registry and its registers are defined and described.
This part also specifies a feature concept dictionary registers. A FCD specifies hydrographical definitions that may be used to describe geographic information. Such a register will improve the IHO’s ability to manage and extend multiple products based on S-100.
- General Feature Model and Rules for Application Schema
The General Feature Model defines a conceptual model of features, their characteristics and associations, and the rules for developing an application schema. This part further deals with conceptual modelling of features and their properties, conceptual modelling of information types and associated attributes, and the development of application schemas and the related rules for such a schema.
The S-100 metadata profile described is divided into three parts and provides specifications for describing, validating and exchanging metadata of data produced by hydrographical organisations. This profile is based on ISO 19115:2003, ISO 19115-2:2006, and ISO 19139:2007. The primary intent of this profile is to describe digital geo-spatial data. However, it can also be used for other products, such as charts, maps, images, textual documents and non-geographic resources. The profile is not limited to ISO 19115 since it can be extended to include additional resources.
- Feature Catalogue
The feature catalogue specifies a framework for organisation and reporting the classification of real world phenomena as geographic data. It defines the methodology for classification of the feature types and specifies how they are organised in a feature catalogue and presented to the users of a set of geographic data. A feature catalogue shall be defined for each product specification. This profile is for defining geographic features at the type level.
- Coordinate Reference Systems
The location of an object shall be defined by means of coordinates, which relate to the feature’s position. This profile describes the elements required to define the referencing by means of coordinate systems and datums. A conceptual schema for describing spatial referencing by coordinates and the minimum requirements for multi-dimensional spatial coordinate references are defined.
- Spatial Schemas
S-100 spatial schema requirements are less comprehensive than ISO 19107, which contains all the information necessary for describing and manipulating the spatial characteristics of geographic features. This part is only a profile of ISO 19107 and contains thus only a subset of the classes. The profile added additional constraints (omitted optional elements or constrained cardinalities) for hydrographical data.
- Imagery and Gridded data
Imagery and gridded data have become common forms of geographic data and there exist many external standards designed to handle such data. S-100 shall not preclude compatibility with external sources of data. This profile aligns with the ISO/TC 211 standards on imagery and gridded data in order to support multiple sources of data and uses the common information structures. This allows the data to be combined with various other data types. This part defines specific grid organisations to be used for hydrographical data and images associated with hydrographical data. Both simple grids and complex multidimensional grids are defined, as well as point sets and TINs.
Portrayal is not included in this version of S-100 and will be developed at a later date.
- Encoding Formats
S-100 does not mandate particular encoding formats. The developer of a product specification can decide on suitable encoding standards and shall then document their chosen format. Encoding is complicated because numerous encoding standards are available. The parts provide guidelines on the selection and documentation of an encoding format.
- Product Specification
A data product specification defines a geo-spatial data product, and describes all the features, attributes and relationships of a given application and their mapping to a dataset. This part describes data product specifications for hydrographical requirements for geographic data products. Its aim is to provide a clear and similar structure for any data product specification to be written.