A Lightning Talk
There are four feature types in the OS NGD Buildings theme. The first two have the same geometry as their equivalent features in OS MasterMap Topography Layer but all with new OS NGD attribution and are covered in the Building Part Feature Type section. The third, added in September 2023, is comprised of merged Building Part features. The fourth, added in March 2025, is newly captured data about access points to certain key public buildings.
Polygon features representing either a complete separate building or a larger building where internal divisions have been dissolved to leave single feature. such as with a hospital or school.
Polygon features representing either a complete separate building or part of a larger building where internal divisions exist from ground to roof level and can be identified externally. Examples include a multi-storey car park, castle or a residential property.
A feature which has a line geometry a represents a wall between two buildings, internal building division or an overhanging building edge.
Access point to an entrance to a major public building (shopping centre, sports stadium, etc.), including attribution as to the type of access.
The OS NGD Buildings data comes in two formats, CSV and GeoPackage (GPKG)
The GeoPackage format comes ready to load into the GIS package of the users choice with different gpkg files for each layer.
The CSV format is more suited for loading into a database. It has all of the same layers in csv format and all the same attribution as the GeoPackage, however instead of storing the geometry in a GIS-ready format, it is stored as a LINESTRING (Building Line), or POLYGON (Building Part/ Building) attribute with all of the vertices stored as co-ordinate pairs in the text file.
These are a new feature type within OS NGD Buildings that have been added in March 2025.
Building Access Locations are points identified by OS where vehicles, pedestrians, or both can enter and/or leave a building.
The data has been derived through field capture by OS Field Surveyors. and is based on externally identifiable access locations.
They are captured for the following buildings:
Hospitals
Railway Stations
Major Transport Interchanges (airports, ferry terminals etc.)
Stadiums and Sports Arenas (>5000 capacity)
Shopping Centres (>50 retail units)
Conference Centres (>500 capacity)
Concert Venues (>1000 people)
‘access_mode’ defines the mode of transport that can use the access location. The values are ‘Pedestrian’, ‘Vehicular’, and ‘Pedestrian And Vehicular’
‘access_purpose’ defines the main function of the access location in normal circumstances. The values are ‘Emergency’, ‘Primary Public’, ‘Private’ and ‘Public’.
‘access_obstruction’ indicates whether there is a possible accessibility obstruction to the access location. The attribute can include a combination of ‘No Obstruction’, ‘Other Obstruction’, ‘Ramp’ and ‘Step’.
‘access_level’ is an indicator of the access location relative to the surface. The values are ‘Above Surface Level’, ‘Below Surface Level’ and ‘Surface Level’.
‘accessedbuildingid’ is a reference to the unique itendifier of the building that the access location is referring to.
Links that may be useful:
This content has been developed from what was originally a Lightning Talk PowerPoint slide set. These slides are available to PSGA members to view and download from the PSGA members area of the OS website
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