OS Open Linked Identifiers Relationships

• TopographicArea (TOID): is a polygon taken form the OS MasterMap Topographic Layer and can depict land, roads and buildings among other things. The OS Linked Identifiers product has only selected the TopographicArea features relate to either an address (typically a building) or a road. 
  
  
• RoadLink (TOID): is taken from the OS MasterMap Highways product and details a road section from junction to junction. 
  
  
• Road (TOID): is taken from the OS MasterMap Highways product and groups a collection of RoadLink to form the full extent of a name road feature (e.g. “The High Street”). 
  
  
• ORRoadLink/ORRoadNode (GUID): is taken from OS Open Roads and depicts the junctions and road sections between them. They are a simplified geometry to that of the OS MasterMap Highways product with some dual carriageways reduced to a single ORRoadLink and some roundabouts/cul-de-sacs reduced to a single ORRoadNode. 
  
  
• Street (USRN): is taken from the OS MasterMap Highways product and like a Road groups together a collection of RoadLinks which form the full extent of a named road within an administrative area. This feature is used to track maintenance for the road feature and is given a Unique Street Reference Number (USRN). 

• BLPU (UPRN):  the Basic Land and Property Unit (BLPU) is taken from AddressBase Premium and gives a Unique Property Reference Number (UPRN) to each address.

Go to the technical specification 

The image above shows all the relationships OS Open Linked Identifiers includes. Each one is available to download individually from the OS DataHub. The following section describes possible use cases for each one.

RoadLink ↔ TopographicArea: RoadLink_TOID_TopographicArea_TOID_2 

Relating the RoadLink feature to a TopographicArea enables the visualisation of data collected and linked to RoadLinks (pollution counts, accidents, traffic speed) and visualise it by colour coding the relevant road surface area.  Additionally, it can be useful for analysis enabling the road surface area to be calculated for a given road section. 

Road↔ TopographicArea: Road_TOID_TopographicArea_TOID_3 

Having links between Road with TopographicArea allows for the full extent of the road to be joined to all the TopographicArea features that represent it. This can be useful to calculate the full surface area for that named road and for displaying data linked to the road name by colour coding the road surface area. 

Street ↔ TopographicArea: Street_USRN_TopographicArea_TOID_4 

Being able to relate a Street USRN to a TopographicArea TOID is useful for calculating the total road surface area for a given USRN.  It can also be useful to display data related to the USRN such as maintenance history and schedule. 

BLPU↔ TopographicArea: BLPU_UPRN_TopographicArea_TOID_5 

Having a link from the BLPU UPRN to a TopographicArea TOID is useful for calculating the area of the building footprint related to an address. It can also be useful to colour code building TopographicAreas for displaying related data for that address such as council tax band.

RoadLink ↔ Road: RoadLink_TOID_Road_TOID_7 

Being able to relate each section of road to it's road name is very useful for validation and can also be useful for aggregating data collected at the RoadLink level for sharing at the Road name level. 

RoadLink ↔ Street: RoadLink_TOID_Street_USRN_8 

The RoadLink TOID to Street USRN is useful for aggregating data collected at a RoadLink level to a USRN for reporting. It is also useful for validating the USRN is the one you’re expecting. 

BLPU↔ RoadLink: BLPU_UPRN_RoadLink_TOID_9 

Knowing which RoadLink access a given property UPRN gives is useful during conveyancing to determine if the road is private or not and carry any maintenance liabilities. It is also useful to be able to relate a RoadLink to all the property UPRNs accessed by it in case you need to notify them about upcoming road works.

Road ↔ Street: Road_TOID_Street_USRN_10 

The primary use case for relating a Road TOID to Street USRN is to validate that the USRN you have related to the road name you’re expecting.  It's also useful for identifying where a single named road is maintained by two different administration areas. 

BLPU ↔ Street: BLPU_UPRN_Street_USRN_11 

Road works are often scheduled using the USRN. Being able to relate a USRN to easily locate the UPRN addresses that are accessed by the road is useful to aid notifying residents of possible upcoming disruption. 

Open Roads RoadLink ↔ OSMM Highways RoadLink: ORRoadLink_GUID_RoadLink_TOID_12 

Open Roads RoadNode ↔ OSMM Highways RoadLink:ORRoadNode_GUID_RoadLink_TOID_13 

These two tables have a very specific use case which is to enable data that is published against an OS MasterMap Highways RoadLink TOID (such as pollution counts, traffic accidents or average vehicle speed)to be visualised with the OS Open Roads product. This enables public data to be visualised for free.