This technical specification provides detailed technical information about OS MasterMap Highways Network – RAMI. It is targeted at technical users and software developers.
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The OS MasterMap Highways Network is the authoritative highway network for Great Britain. It brings together Ordnance Survey’s large-scale road and path content, the National Street Gazetteer (NSG), the Trunk Road Street Gazetteer (TRSG) and the Scottish Street Gazetteer (SSG).
OS MasterMap Highways Network is made up of four product schemas: Linear Highway Network, Highways Dedication, Routing and Asset Management Information and Highways Water Transport Network. These four schemas, shown in the diagram below, create three products which are a part of the OS MasterMap Highways Network family:
OS MasterMap Highways Network – Roads
OS MasterMap Highways Network – Routing and Asset Management Information
OS MasterMap Highways Network – Paths
This technical specification covers the OS MasterMap Highways Network – Routing and Asset Management Information (from here, referred to as RAMI) product specification, providing a focus on the RAMI features. To use this product, you will have received the features which make up the Roads product. For further details on the Roads or Paths products, please see their respective Technical Specifications.
All features that comprise the OS MasterMap Highways Network product will be assigned a persistent identifier, which in most instances is an Ordnance Survey TOID (Topographic Identifier). For features which have originated from the National Street Gazetteer, the persistent identifier will be either a Unique Street Reference Number (USRN) for Street features or a unique ID for Maintenance, Reinstatement, Special Designation and Highways Dedication.
Identifiers shall be encoded in three properties in the data:
gml:id – This feature identifier consists of the shorthand prefix namespace and local identifier which is used to uniquely identify and reference the feature within the dataset, for example, osgb4000000009461245.
gml:identifier – This is a global feature identifier and can be used to identify and reference the feature within other datasets, for example, http://data.os.uk/id/4000000009461245.
inspireID – This is a complex property made up of a localId, namespace and versionId which uniquely identifies the feature and version within an INSPIRE dataset.
Where features have come from OS MasterMap ITN Layer, the identifier will be persistent and correspond to the same feature in ITN.
The gml:id is used throughout the OS MasterMap Highways Network products as the identifier used to reference to other features.
TOIDs (Topographic Identifiers) are strings of up to twenty characters which comprise two parts:
Namespace: This is either a HTTP URI (http://data.os.uk/) or a shorthand prefix (osgb)
Local identifier: A 16-digit numeric string (0-9)
gml:id – ‘osgb4000000009461245’
localId – ‘4000000009461245’
identifier - ‘http://data.os.uk/4000000009461245’
USRNs (Unique Street Reference Numbers) are strings of up to 12 characters which consist of 2 parts:
Namespace: This is either a HTTP URI or shorthand prefix (‘usrn’)
Local identifier: Up to an 8-digit numeric string (0-9)
gml:id – ‘usrn82101225’
localId – ‘82101225’
identifier - ‘http://data.os.uk/82101225’
Although the gml:id is the identifier used for referencing features in OS MasterMap Highways Network products, the localId is the identifier used by the National Street Gazetteer, National Land and Property Gazetteer and the OS AddressBase family of products.
Unique IDs for Maintenance, Reinstatement, and Special Designation are strings of up to 17 characters which consist of two parts:
Namespace: This is either a HTTP URI (http://data.os.uk/) or shorthand prefix (‘id_’)
Local identifier: 14-character alphanumeric string
The ID for HighwayDedication is a string of up to 25 characters comprised of the characters “esu” followed by three parts separated by “_” (underscore):
LHA authority code
ESU it references
Dedication code in the NSG
For example: esu4720_4280330430163_8, esu4720_4280340431456_11
gml:id – ‘id_3700MA01862142’ or ‘esu4720_4280330430163_8’
localId – ‘3700MA01862142’ or ‘esu4720_4280330430163_8’
identifier - ‘http://data.os.uk/3700MA01862142’ or ‘https://data.os.uk/id/ esu4720_4280330430163_8’
OS MasterMap Highways Network – RAMI will be supplied in two formats: Geography Markup Language (GML 3.2.1) and GeoPackage. Both formats are compressed into a regular zip file (.zip).
OS MasterMap Highways Network– Roads and OS MasterMap Highways Network – Paths will be supplied in three formats: Geography Markup Language (GML 3.2.1), GeoPackage and vector tiles. All formats are compressed into a regular zip file (.zip).
OS MasterMap Highways Network extends the INSPIRE Transport Networks (Road and Water) Technical Specification (version 3.2).
OS MasterMap Generic Network model extends the INSPIRE Base Models - Generic Network Model (version 3.0rc3).
OS MasterMap Highways Network extends the INSPIRE Specification to include the additional properties required by BS 7666-1:2006 defined within the National Street Gazetteer (NSG) Data Transfer Format (DTF) and Scottish DTF (SDTF) to ensure that conformance to both INSPIRE and BS7666-1:2006 can be achieved.
The data structure is described by means of UML class diagrams and accompanying data dictionary tables. The specification conforms to the rules for application schema 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 allow users to easily distinguish the INSPIRE feature classes (coloured grey) from the Ordnance Survey feature classes which extend the INSPIRE specifications (coloured orange). All code list classes are coloured blue, enumeration classes are green and data types/union classes are purple (see diagram below).
The data dictionary tables use orange for a feature type, blue for a code list, green for enumerations, and purple for data types.
Class names are conceptually meaningful names (singular noun) in UpperCamelCase.
Class names end in “Value” where the class is assigned the stereotype <<CodeList>> or <<Enumeration>>.
Class names shall end in “Type” where the class is assigned the stereotype <<DataType>>.
Property names (attributes and associations) are in lowerCamelCase.
The following stereotypes are used on UML elements:
| Stereotype | UML Element | Description |
|---|---|---|
<<ApplicationSchema>> | Package | Parent package containing sub-packages and elements that comprise part of the modular specification. |
<<FeatureType>> | Class | A spatial object type. [ISO 19136]. |
<<Type>> | Class | A structured data type with identity. |
<<DataType>> | Class | A structured data type without identity. [ISO/TS 19103]. |
<<Union>> | Class | A structured data type without identity where exactly one of the properties of the type is present in any instance. |
<<Enumeration>> | Class | A fixed controlled set of values for a free text data type. |
<<CodeList>> | Class | A controlled set of values for a free text data type that may be extended. |
<<Voidable>> | Property | A property that is required but is either not currently captured (unknown) or is partially populated (unpopulated). |
<<LifecycleInfo>> | Property | Property considered part of the life cycle information. |
Constraints are defined on the Class using human readable language only. Constraints are displayed on class diagrams below. These constraints are used to define co-constraints or restrict INSPIRE properties only.
There are three key types of relationship defined between classes:
Generalisation/Specialisation – used to denote either:
An extension relationship. The target class represents the same real-world entity and is extending it to include additional properties not defined on the parent class.
This class has the same name as the class it is extending.
Or:
A sub-typing relationship. The target class defines a specialised sub-type of parent feature. For example, TransportNode is a specialised sub-type of a generic Node class.
Directed Association – used to denote relationships between features. These relationships are encoded as references to the related feature via the identifier assigned in the gml:id. The directed end shall be assigned a name which describes the relationship between the two features and a multiplicity.
Aggregation – used to denote part-of relationships. Aggregations are used to describe loose part-of relationships. If the parent feature ceases to exist, then the part feature can continue to exist. For example, a Road Name may cease to exist, but the Road will still exist.
This technical specification includes the following sections:
