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Themes

Themes provide a logical collection of features grouped according to their classification or relationship with other features. There are three themes within OS MasterMap® Integrated Transport Network™ Layer (ITN):

All themes are based on a relational data model that uses TOID references to associate routing information to the physical road or path network.

 

Road and RRI relational data model

The elements of the Road Network model can be categorised into four distinct groups (see figure 1).

Figure 1: Road and RRI relational data model (elements are categorised into four groups)

 

The networkMember group (figure 2) represents physical parts of the network, such as roads and junctions, paths and junctions, or implied parts of the network, such as the FerryLink feature. There is also a reference from RoadLink and RoadNode features to the corresponding TopographicArea polygons in the OS MasterMap Topography Layer that form the carriageway. These polygons are not included with the ITN, so they are not considered part of the networkMember group.

The roadMember group contains the information on road names and numbers and is therefore referenced to as many road link features as are deemed to share that name or number.

The InformationPoint provides the junction number and numbers of the roads intersecting at that junction. This is the only element that does not reference any other member.

The remaining elements in the roadinformationMember group form the contents of the RRI theme; these apply either to a RoadLink feature, for the majority, or a RoadNode feature. The RRI may apply to the whole link, part of the link or a specific point along the link and includes information. It may also apply to a collection of links that, taken together, form a route where direction of flow of traffic along that route is controlled.

 

Urban Paths and PRI relational data model

Figure 2 shows the relational data model for Urban Paths, with the elements coloured to categorise them into four distinct groups.

Figure 2: Urban Paths and PRI relational data model (elements are categorised into four groups)

The networkMember group represents physical parts of the network, such as paths and junctions, or implied parts of the network, such as the FerryLink feature. There is also a reference from PathLink and PathNode features to the corresponding topographicArea polygons in the OS MasterMap Topography Layer that form the carriageway (this is not populated within the first release of ITN Urban Paths but will be at a later date). As these polygons are not included with ITN, they are not considered part of the networkMember group.

The pathMember contains the information on path names and is therefore referenced to as many PathLink features as are deemed to share that name.

The remaining pathinformationMembers form the contents of PRI; these apply either to a PathLink, for the majority, or a PathNode. The PRI may apply to the whole link, part of the link or a specific point along the link and includes information. It may also apply to a collection of links that taken together form a guidance route directing the flow of pedestrians along the full route.

In this section:

ITN Technical specification – home

Purpose of this specification

ITN network features

ITN data structure

Overview of ITN themes

ITN Road Network theme

ITN Road Routing Information (RRI) theme

ITN Urban Paths theme

ITN Path Routing Information (PRI) theme

ITN Layer qualifiers

Feature types and attribution in the Road Network theme

Feature types and attribution in the Road Routing Information theme

Feature types and attribution in the Urban Paths Network theme

Feature types and attribution in the Path Routing Information theme

Descriptions of ITN Layer attributes

Attribution checklists for the Road Network and Urban Paths Network themes

ITN attribute definitions and values

ITN GML output format

ITN Layer GML examples

ITN character set

ITN weights and width attribution

ITN steep gradient attribution

This web page is part of the technical specification for OS MasterMap® Integrated Transport Network™ Layer. For the terms that apply to use of this specification, refer to Purpose of this specification.

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