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This technical specification provides detailed technical information about OS MasterMap Water Network Layer. It is targeted at technical users and software developers.
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OS MasterMap Water Network Layer provides a three-dimensional structured link and node network of Great Britain's watercourses. A link represents the approximate central alignment of a watercourse and includes inland rivers, streams, tidal water, lakes, lochs and canals; links are attributed with additional information, including flow direction and primary flow paths. Where watercourses are obscured or underground, connectivity is provided where Ordnance Survey capture processes or accepted sources can infer the connection.
The OS MasterMap Water Network Layer product is in geometric sympathy with the underlying topographic features that comprise OS MasterMap Topography Layer. Polygons and lines representing the water area and its banks are not supplied in this product but will continue to be maintained and supplied as part of the OS MasterMap Topography Layer product.
Ordnance Survey provides persistent managed identifiers as TOIDs. TOIDs are strings of up to twenty characters, starting with ‘osgb’; the remaining characters are digits (0 to 9). In an INSPIRE encoded dataset such as this, each feature carries its identifier in three ways, as described below:
gml:id: Required by Geography Markup Language (GML). This matches the pattern in other OS MasterMap products.
gml:identifier: Recommended by INSPIRE and the UK INSPIRE project. This formats the TOID into a persistent URI, using http://data.os.uk/id/ as a namespace, instead of ‘osgb’. This does not mean that the water network features are available as linked data.
net:inspireId: The localId is set to the TOID (without ‘osgb’), and the namespace set as above. The
INSPIRE identifier model does not fit with SF0; it does fit with level 1.
The feature version is encoded as the versionId within the INSPIRE Identifier.
OS MasterMap Water Network Layer will be supplied in Geography Markup Language (GML) 3.2.1, GeoPackage and vector tiles formats.
OS MasterMap Water Network Layer is based on the INSPIRE Hydrography Data Specification, which itself is based on the ISO TC211 family of open standards.
OS MasterMap Water Network Layer extends the INSPIRE specification.
The data structure is described below by means of unified modeling language (UML) class diagrams and accompanying tables containing text. The UML diagrams conform to the approach specified in ISO 19103 Conceptual schema language and ISO 19109 Rules for application schema, as adopted by INSPIRE.
Colour conventions have been used in the diagrams and tables to distinguish the INSPIRE specification from the additional properties that have been added in this specification. In the UML diagram, classes from the INSPIRE Data Specifications are coloured grey, whereas classes in the Ordnance Survey product specification are coloured orange. All code lists are coloured blue, enumerations are coloured green and data types are coloured purple, which can be seen in the figure below. The tables which follow in this Technical Specification use orange for a feature type, blue for a code list, green for enumerations and purple for data types.
This technical specification includes the following sections:
