Source of OS Open Names

OS Open Names is updated from Ordnance Survey’s data content stores.

Settlements

Settlements are sourced from an internal OS data store. For LocalType City and Town, the geometry supplied is the notional centre of the settlement (the position that the majority of informed people would accept as being the 'centre' of the settlement) and the position has been manually captured.

For all other settlement types, the position has been generated from the major road junction within the settlement, using OS MasterMap Highways Network.

Postcodes

A single point is taken from Ordnance Survey’s database for the geometry of a postcode which is the notional centre created from all the addresses within the postcode unit.

Roads

The geometry for a road feature is derived from OS MasterMap Highways Network. The point has been calculated by finding the vertex closest to the centre of the bounding box.

A road feature will always have a point based on the entire road as shown in the diagram below. Furthermore, where a Road Name intersects a settlement or a Road Number intersects a City or Town, an additional point is created within the settlement.

Calculating points for roads in OS Open Names.

Numbered Road

For each section of road that intersects a City or Town, an additional point is calculated as per the method above. The image below shows an example of a Numbered Road that intersects two towns, the blue box is the bounding box for the entire road and the blue cross is the vertex closest to the centre of the bounding box. For each Town or City the Numbered Road intersects, a bounding box is created for the section within the Town or City, shown in red. The closest vertex to the centre of the bounding box is then selected as the point, shown by the red cross. The red features will reference the Topographic Identifier (TOID) of the blue feature through the relatedSpatialObject attribute.

Calculating points for numbered roads that pass through settlements.

Named Road

For each section of road that intersects a settlement, an additional point is calculated as per the method above. The image below shows an example of a Named Road that intersects two settlements; the blue box is the bounding box for the entire road and the blue cross is the vertex closest to the centre of the bounding box. For each settlement the Named Road intersects, a bounding box is created for the section within the settlement, shown in red. The closest vertex to the centre of the bounding box is then selected as the point, shown by the red cross. The red features will reference the TOID of the blue feature through the relatedSpatialObject attribute.

Calculating points for named roads that pass through settlements.

The points are queried against Boundary-Line to populate the contextual geography attributes such as DISTRICT_BOROUGH or COUNTY_UNITARY. The inPostcodeDistrict attribute is populated for roads only and uses the postcode district.