🆕Comparison of Transport Network Products

Comparing OS MasterMap Highways Network products to the OS NGD Transport Theme.

The OS MasterMap Highways Network products are expected to become End of Life in Spring 2027, with a formal notice anticipated shortly. Subject to confirmation in that notice, Ordnance Survey will no longer maintain or publish updates to these products as of the confirmed date, and access to the products will also be withdrawn from the OS Data Hub, OS Features API, and OS Vector Tile API.

For the latest updates and information on this and other products, please refer to our strategic product roadmap.

Overview

The purpose of this page is to provide a technical summary of things to consider when migrating from OS MasterMap (OSMM) Highways Network products to corresponding feature types within the OS National Geographic Database (OS NGD) Transport Theme. It covers data supply and formats, as well as a comparison of the attribution of the OSMM and OS NGD products.

The OSMM Highways Network product family provides an authoritative road and path network for Great Britain. It includes a road network, a path network, connectivity across British islands through a ferry network, plus routing and asset management information.

The product family includes three products:

• OS MasterMap Highways Network – Roads

• OS MasterMap Highways Network – Routing and Asset Management Information (RAMI)

• OS MasterMap Highways Network – Paths

All the data within these products is present in the OS NGD Transport Theme within the Transport Network and Routing and Asset Management Information (RAMI) Collections. OS NGD data offers numerous additional data enhancements when compared to the OSMM Highways Network products, including:

• Geometry being available for every feature

• Simpler attribution, with no complex types or arrays

• Existing feature type attribution has been enhanced, including information on the presence of pavements, trams and street lighting

• Speed data is included, now freely available for Public Sector Geospatial Agreement (PSGA) Members

• A full rail network is available

New OS Multi-modal Routing Network product

For existing OSMM Highways Network customers interested in routing use cases, the new OS Multi-modal Routing Network (OS MRN) product might be a viable alternative to OSMM Highways Network and the OS NGD Transport Theme.

OS MRN is a fully connected routable network dedicated for the multi-modal routing of people and goods. The product is designed for use in routing applications and contains multi-modal connectivity between road, rail, path and ferry networks, brought together by modal change points to enable transition between modes. 

For routing use cases, OS MRN offers the following advantages over OSMM Highways Network products:

• It's designed specifically for routing

• There's full connectivity between different networks

• It's a single dataset that incorporates routing information and speed data

• It follows the OpenStreetMap (OSM) schema to enable straightforward import into routing applications, particularly open-source routing engines

• The modal change points enable connectivity with key transport sites

• There's easy integration with third party bus and train timetable datasets

• Less processing required to use it – for example, OS has implemented the logic to determine what links are suitable for walking

Please see the StoryMap and Lightning Talk for an introduction to OS MRN or the full details on our documentation site.

Feature types and attribution

OS NGD data has been enriched with attribution to ensure that it's straightforward to navigate and query. Attribute names have also been simplified to make them easier to understand.

The following two pages detail the feature type mappings from OSMM Highways Network to the corresponding feature types found within the two OS NGD collections (Transport Network and RAMI):

• RAMI feature types

• Roads and Paths feature types

The sub-pages also include detailed attribution comparisons between the products. For example, that the data found in Road Link's formOfWay attribute now resides in the OS NGD's Road Link description attribute. However, any attribution that is consistent across multiple feature types (for example, relating to lifecycle and metadata) is covered below.

Unique identifiers

OSMM Highways Network

In OSMM Highways Network products, three different persistent managed identifiers are supplied:

1. Unique Street Reference Number (USRN): This is used for the Street Feature Type only.

2. A unique identifier (id): A unique character string used to identify the Maintenance, Reinstatement, Special Designation and Highway Dedication Feature Types.

3. Topographic Identifier (TOID): These are used for all the other feature types within OSMM Highways Network.

These three different identifiers also form part of the inspireId and the identifier attributes.

OS NGD Transport Theme

The OS NGD Transport Theme uses a new identifier called the OS Identifier (OSID) to uniquely identify features. The OSID is a Universally Unique Identifier (UUID) and requires no centralised authority to ensure uniqueness. The OSID is present in all OS NGD Transport Theme feature types except for Street, which uses the USRN still.

The new OS NGD feature types also contain toid or authorityid attributes, where applicable, to enable the migration from OSMM Highways Network identifiers.

When we cease to maintain or publish updates to OSMM Highways Network products, new TOIDs will also cease to be generated and therefore will not appear in new OS NGD Transport Theme features.

Lifecycle and metadata

The feature types within the OSMM Highways Network products contain attributes relating to their lifecycle, including reasonForChange, versionId and beginLifespanVersion; comparable information can be found in the changetype, versiondate, versionavailablefromdate and versionavailabletodate OS NGD attributes.

Relationships between feature types

In OSMM Highways Network, the references between Road, Street or Path and the Road or Path Link were arrays of complex types, with additional attribution used to identify if the identifier was, for example, a Road or a Street.

In OS NGD, simple cross-reference tables are supplied that allow linking between the feature types. The diagram below shows how this works for road-related feature types, with the cross-reference tables shown in grey. More detail can be found on the OS NGD Transport Network lightning talk page.

OS NGD roads data structure diagram.

Arrays and multiple values

In Geography Markup Language (GML) format, many of the attributes supplied in OSMM Highways Network feature types have a multiplicity of greater than one and are therefore supplied as arrays. For example:

• roadName: This attribute has a multiplicity of [0..2] , i.e. between zero and two values can be present.

• formsPartOf: This attribute has a multiplicity of [0..*] , i.e. there is no minimum or maximum to the number of values present.

As the GeoPackage format does not natively support arrays, when OSMM Highways Network products are supplied in GeoPackage, these attributes are concatenated into comma-separated strings.

When considering the download formats of OS NGD, i.e. GeoPackage and comma-separated values (CSV), neither format natively supports arrays; therefore, there are two approaches that are used:

1

Flattening approach

Where an OSMM Highways attribute has a finite number of values allowed, arrays attributes are 'flattened' into new multiple attributes. For example:

• The roadName attribute in the Road Link Feature Type becomes name1_text and name2_text.

• For complex data types like DesignatedNameType, found in the Road Feature Type (designatedName > namingAuthority > identifier), this corresponds to multiple attributes that are prefixed with designatedname* as per the below:

  • designatedname1_text / designatedname2_text

  • designatedname1_language / designatedname2_language

  • designatedname1_responsibleauthorityidentifier / designatedname2_responsibleauthorityidentifier

  • designatedname1_responsibleauthorityname / designatedname2_responsibleauthorityname

2

Reference table approach

Where an OSMM Highways attribute has an unlimited number of values allowed, a separate reference table is provided. For example, within the Road Link Feature Type, the formsPartOf attribute references the identifiers of the Road or Street to which the Road Link forms part of.

In OS NGD, the 'parent' feature type (in this example, Road and Street) both have a Road Link Reference table supplied either within the GeoPackage as a separate table or as an additional CSV file, depending on the format requested, that will be named:

• trn_ntwk_road_rdlinkref

• trn_ntwk_street_rdlinkref

When accessing OS NGD data via OS NGD API – Features, this approach is slightly different; please see the below content for an example.

OS NGD API – Features approach

When accessing the OS NGD via OS NGD API – Features, feature types with reference tables return the attribution as part of your GeoJSON as an array of objects.

Simplified example from trn-ntwk-street Feature Type:

"properties": {
	"usrn" : 12345678
	"roadlinkreference": [
		{
			"roadlinkid": "5788cb74-89b6-4af9-8347-9b93b6809156",
			"streetversiondate": "2024-06-12",
			"usrn": 12345678
		},
		{
			"roadlinkid": "ef3b433b-369b-47d0-a16b-f3536b8b06bd",
			"streetversiondate": "2024-06-12",
			"usrn": 12345678
		}
	]
}

Currency

The OSMM Highways Network products and the two comparable OS NGD transport collections (Transport Network and RAMI) are refreshed on a monthly basis.

Data supply

File formats

OSMM Highways Network

OS MasterMap Highways Network products are available in:

• GML (Geography Markup Language)

• GeoPackage

• Vector tiles (Roads and Paths products only; format not available for the RAMI product)

The products are also currently supplied in the OS Features API and the OS Vector Tile API (although access to the products will be removed from both APIs in Spring 2027).

OS NGD Transport Theme

The OS NGD Transport Theme is available in:

• GeoPackage

• CSV (comma-separated values)

• GeoJSON

• Vector tiles

The OS NGD download service of OS Select+Build supplies GeoPackage and CSV formats, while OS NGD API – Features supplies GeoJSON and OS NGD API – Tiles supplies vector tiles.

The OS NGD Documentation site contains further guidance on the differing formats and APIs available:

• OS NGD file formats and naming

• Getting Started with OS NGD API – Features

• Getting Started with OS NGD API – Tiles

Download data ordering options

OSMM Highways Network

Through the OS Data Hub, it is currently only possible to order OSMM Highways Network products in one of the following options:

• GML (Geography Markup Language): Individual 5km² tiles, available for the whole of Great Britain or covering a specified area of interest

• GeoPackage: Single file containing full Great Britain coverage

• Vector tiles: Single MBTiles file containing full Great Britain coverage

OS NGD Transport Theme

All OS NGD download data is supplied through OS Select+Build in the OS Data Hub. OS Select+Build offers a much more tailored experience to ordering and downloading OS data with an improved range of options, including:

• All formats (including GeoPackage and vector tiles) are available for areas of interest, not just as a full Great Britain download.

• Ability to filter your supply on select attributes such as description, roadClassification and nationalRoadCode , as well as various name and authority attributes, enabling you to receive only the features that you require.

The OS NGD Documentation site contains guidance on downloading with OS Select+Build and using and loading OS NGD data in both CSV and GeoPackage formats:

• Downloading with OS Select+Build

• Getting Started with CSV

• Getting Started with GeoPackage

Help and support

Supporting links

The OS NGD Documentation site has further information that you may find useful. Some particularly relevant sections that may aid you with migration are:

• OS NGD Fundamentals

• OS NGD Transport Theme

Contact us

If you have any questions, need assistance, or want to provide feedback, please don't hesitate to reach out to us at os.uk/contact-us.