Building Feature Type
A Lightning Talk
What are the layers in OS NGD Buildings?
There are three 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 rest of this page deals with the Building Feature Type
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.
What formats does the OS NGD Building data come in?
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.
What are Building Features?
Building Features are a compound feature made up of all the connected Building Part features that comprise a large single feature, such as a hospital, school, industrial site, multi-storey car park, large residential block, sports stadium etc. This allows users to select a single Building feature that represents a complex building as opposed to selecting multiple individual Building Part features, similar in principle to Compound Structures.
There are also three cross reference tables that list the links between:
Address UPRN – Building
Building Part – Building
Site - Building
In the example here the Building feature for Raigmore Hospital is made up of 41 separate Building Parts
Building Feature Type Attribution
The Building Feature Type, new from 09/2023, represents a single compound feature for complex buildings made of multiple smaller Building Parts
There is a count of the number of Building Part features making up the larger compound Building feature
Attributes to say if the Building is in a Land Use site or not and if so, how many, in the example below there two
Attribution as to whether this is the main building and if not, what the ID of the main building is
New attribution about Building use, alongside the existing Land Use Tier A attribution from the Building Part
Counts of the number of Addresses and if they are Residential, Commercial or Other
Whether the building is connected to another building and if it is Standalone, Semi-Connected, End-Connected or Multi-connected and a count of the number of connected buildings
Building Description
Definition: A text field giving a simple concise definition of what the building is.
Provides a Building description attribute for all OS NGD Building features
This attribute is created using OS Address and Land Use Site data. There are three steps to this: identify Static Caravans; use Land Use data and Primary Sites; use addressing for all others.
The address-centric values use attribution from the address, sites, main building, building use, building type to derive a Building Description
Includes standard terminology for residential buildings e.g. detached house, mid-terraced house, end-of-terrace, etc.
Includes ‘Mixed’ description where the building has more than one use (also Building Use contains Mixed Use values)
Building Age
From 03/2024 there has been an expansion of the attribution on the Building Feature Type:
Definition: The period of construction of the principal part of a building
These attributes have been created using third party data from Verisk (pre-2021) and supplemented with OS data (2021 onwards).
It is only for NGD Buildings that contain an address. This means that if a Building Part has an address, and a construction period, and it is part of a larger Building feature with other Building Parts that do not have an address, the resulting Building feature will inherit the construction period of the single addressed part of the Building. This can create anomalies. Where a complex Building has multiple construction ages from different Building Parts, the oldest date is used.
It contains two main attributes – a period of construction (a date range) and year of construction (a specific year), where available.
The period of construction ranges vary for earlier periods and move to consistent decadal ranges from 1980 onwards. Earlier than 1919 is it difficult to identify commercial buildings so there is a catch-all range of pre-1919 as well as more defined ranges going back to 1837 mainly covering residential buildings
Additional metadata includes the third-party building age provenance which identifies the source and capture type used by Verisk e.g. Domestic EPC (extraction from another source) or Infill Modelling (the data has been modeled)
The additional metadata gives more information to make more informed decisions about the data
Construction Type
Definition: The material the outer skin of the principal part(s) of a building is made from.
The primary construction material of the building which can be the observed external material, but in some cases the underlying construction, mainly depending on the source data.
This attribute is created using 3 sources: OS Data to identify Static Caravans; OS Field Surveyors for new or edited buildings and third-party data (Verisk) for all others
Only buildings that contain address are within scope. Where multiple Building Parts make up a single Building, the ‘constructionmaterial’ attribute will be derived from the Building Part with the largest area
The ‘constructionmaterial’ attribute can contain a material type, but also can be Unknown where we don’t know the material and null if the buildings are out of scope (domestic outbuildings like sheds and separate garages).
Additional metadata includes the third-party construction material provenance which identifies the source and capture type used by Verisk e.g. Domestic EPC (extraction from another source) or Infill Modelling (the data has been modeled)
Basement Presence
Definition: An indicator whether a building has a basement or other underground occupiable space
This attribute is created from 3 sources: OS Surveyor, OS Address data (Address Authority) and 3rd party supplier (Verisk).
It provides two new attributes - Basement Presence (basementpresence) and Self-Contained flat presence (basementpresence_selfcontained).
Values for both these attribute are: Present, Not present, Unknown, Null. As only buildings that contain address are within scope, Null is used for buildings that are out of scope like garages, sheds, etc.
The ‘basementpresence_thirdpartyprovenance’ attribute shows where the data has come from and includes sources such as HMLR, VOA, EPCs, Historic England, CADW and Historic Environment Scotland as well as infill modelling and address analysis.
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
Last updated
