# Building Feature Type ## What are the layers in OS NGD Buildings? 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](/more-than-maps/data-demonstrators/topography-demonstrators/os-ngd-buildings/building-part-and-building-line-feature-types.md) 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](/more-than-maps/data-demonstrators/topography-demonstrators/os-ngd-buildings/building-access-feature-type.md) to certain key public buildings. {% tabs %} {% tab title="Building" %}

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. {% endtab %} {% tab title="Building Part" %}

Image of Building Part Features — Building Part

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. {% endtab %} {% tab title="Building Line" %}

Image of Building Line Features — Building Line

A feature which has a line geometry a represents a wall between two buildings, internal building division or an overhanging building edge. {% endtab %} {% tab title="Building Access Point" %}

Image of Building Access Point Features — Building Access Point

Access point to an entrance to a major public building (shopping centre, sports stadium, etc.), including attribution as to the type of access. {% endtab %} {% endtabs %} ## 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

Image comparing Building and Building Part Features for a Hospital — 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

Image showing Buildings reference Land Use polygons — Example attribution for a Building feature

## Building Description Definition: A text field giving a simple concise definition of what the building is. This was added in **Version 2** of Buildings in March 2024. * 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)

Map of Buildings themed by Building Description — Buildings styled by Building Description

## 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 This was added in **Version 2** of Buildings in March 2024. * 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

Map of Buildings styled by Building Age Period — Buildings styled by Building Age Period

## Construction Type Definition: The material the outer skin of the principal part(s) of a building is made from. This was added in **Version 2** of Buildings in March 2024. * 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)

Map of Buildings styled by Construction Type — Buildings styled by Construction Type

## Basement Presence Definition: An indicator whether a building has a basement or other underground occupiable space. This was added in **Version 2** of Buildings in March 2024. * 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.

Map of Buildings styled by Basement Presence — Buildings styled by Basement Presence

## Number of Floors Definition: The maximum number of occupiable floors at or above ground level within a residential or office building. This was added in **Version 3** of Buildings in September 2024. This attribute is created from 3 sources: * OS observed data (0.5% coverage) – Field / Remote Survey, Verified Customer Feedback data, or targeted desk-based data improvement * Energy Performance Certificate (EPC) data (1%) – currently only for England and Wales * OS modelled data (98.5%) – Uses a combination of building height data, Local Authority address data, EPC data (details no. of floors at UPRN level), and a Machine Learning Regression Model (utilises topographic data to more accurately predict number of floors in a locality) to derive number of floors in each building. This figure is then rounded up/down to the nearest whole number. The estimated conformance level is 95% for buildings with 1 to 2 floors. For buildings with 3-9 floors, 92% will have the correct number of floors recorded (±1 floor) when compared with the real world. Buildings with 10 or more floors, have an accuracy of 85% (±1 floor). This enhancement provides a new attribute – ‘numberoffloors’ which is an integer output with values ranging from 1-99. This attribute excludes basements and plant rooms, etc. on the roofs of buildings. In addition: * Residential buildings must contain one or more residential address AND be the main building in an OS Land Use Site. * Office buildings must contain 50% or more office addresses. Therefore, some residential buildings will not be in scope at this time or some unexpected buildings, such as cathedrals, may be in scope.

Map of Buildings styled by Number of Floors — Buildings styled by Number of Floors

## Building Height Definition: Height attribution for the building feature type. This was added in **Version 4** of Buildings in March 2025. This attribute is created in three steps: 1. Derive Height Data – data is derived using Ordnance Survey’s photogrammetrically created Digital Terrain Model (DTM) and Digital Surface Model (DSM). 2. Derive Building Part Height – by intersecting the Building Part polygons with the DTM and DSM and, through using some additional calculations and algorithms, the associated height values for each building part can be extracted. 3. Derive Building Height - The Building polygon inherits the most extreme absolute values from all the constituent Building Parts which make up the Building (e.g., the lowest absolute minimum value and highest absolute roof base/maximum value). The enhancement includes five height attributes. These are: * height\_absolutemin\_m – minimum lowest point extracted from the DTM within the footprint of the Building. * height\_absoluteroofbase\_m – maximum highest point extracted from the DSM where the external building walls intersect with the roof. * height\_absolutemax\_m – maximum highest point extracted from the DSM within the footprint of the Building. * height\_relativeroofbase\_m – the lowest ground point extracted to the tallest roof base point extracted from all constituent Building Parts combined. * Height\_relativemax\_m – the lowest ground point extracted to the tallest roof maximum point extracted from all the constituent Building Parts combined. * ‘height’\_confidencelevel’ is an attribute which indicates the quality of the data. It includes ‘High’, ‘Moderate’, ‘Low’, ‘Incomplete’ and ‘NULL’. There is [more detail](https://docs.os.uk/osngd/code-lists/code-lists-overview/builtstructureheightconfidencevalue) on the docs platform.

Map of Buildings styled by Building Height — Buildings styled by Building Height

## Roof Material Definition: The primary roof material present on the building. This was added in **Version 4** of Buildings in March 2025. This attribute has been derived from Ordnance Survey’s imagery using a Machine Learning Model. An Automatic Feature Extraction algorithm has then been used to extract the primary material that the roof is comprised of This enhancement provides a new attribute – ‘roofmaterial\_primarymaterial, which includes ten possible values which are [listed on the docs platform](https://docs.os.uk/osngd/code-lists/code-lists-overview/roofmaterialvalue) ‘roofmaterial\_confidenceindicator’ is an attribute that indicates the quality of the data. These provide context on factors at time of capture which could have influenced the confidence in the data. [More detail](https://docs.os.uk/osngd/code-lists/code-lists-overview/roofconfidenceindicatorvalue) on this can be found on the docs platform. The scope is all buildings > 4sq m that are in OS topographic data. However, this is subject to the availability of imagery and height models.

## Solar Panel Presence Definition: An indicator of whether solar panels are present on the roof of a building. This was added in **Version 4** of Buildings in March 2025. This attribute has been derived from Ordnance Survey’s imagery using a Machine Learning Model. An Automatic Feature Extraction algorithm has then been used to extract the presence of solar panels on building roofs. This enhancement provides a new attribute – ‘roofmaterial\_solarpanelpresence’, which includes these values: ‘Present’, ‘Not Present’, ‘Unknown’ or ‘NULL’. ‘roofmaterial\_confidenceindicator’ is an attribute that indicates the quality of the data. These provide context on factors at time of capture which could have influenced the confidence in the data. The scope is all buildings > 4sq m that are in OS topographic data. However, this is subject to the availability of imagery and height models.

Map of Buildings styled by Solar Panel Presence — Buildings styled by Solar Panel Presence

## Green Roof Presence Definition: Indicates whether the roof of the building is at least partially covered with vegetation. This is usually specifically installed on a growing medium with a waterproof membrane for environmental reasons. This was added in **Version 4** of Buildings in March 2025. This attribute has been derived from Ordnance Survey’s imagery using a Machine Learning Model. An Automatic Feature Extraction algorithm has then been used to extract the presence of green roofs. This enhancement provides a new attribute – ‘roofmaterial\_greenroofpresence’, which includes these values: ‘Present’, ‘Not Present’, ‘Unknown’ or ‘NULL’. ‘roofmaterial\_confidenceindicator’ is an attribute that indicates the quality of the data. These provide context on factors at time of capture which could have influenced the confidence in the data. The scope is all buildings > 4sq m that are in OS topographic data. However, this is subject to the availability of imagery and height models.

Map of Buildings styled by Green Roof Presence — Buildings styled by Green Roof Presence

## Roof Shape Definition: A simple description of the predominant form of the roof. This was added in **Version 4** of Buildings in March 2025. This attribute has been derived from Ordnance Survey’s imagery and Digital Surface Model (DSM). An Automatic Feature Extraction algorithm has extracted these shapes. * 'roofshapeaspect\_shape’ indicates the predominant form of the roof and includes these values: ‘Flat, Pitched, Mixed, Unknown’. [More detail](https://docs.os.uk/osngd/code-lists/code-lists-overview/roofshapevalue) can be found on the docs platform * ‘roofshapeaspect\_areapitched\_m2’ and ‘roofshapeaspect\_areaflat\_m2’ provide a breakdown of the total roof area that are pitched or flat. * ‘roofshapeaspect\_confidenceindicator’ is an attribute that indicates the quality of the data. These provide context on factors at time of capture which could have influenced the confidence in the data. The scope is all buildings > 4sq m that are in OS topographic data. However, this is subject to the availability of imagery and height models.

Map of Buildings styled by Roof Shape — Buildings styled by Roof Shape

## Roof Aspect Definition: A set of attributes that describes the key elements on the alignment(s) of a building roof. This was added in **Version 4** of Buildings in March 2025. This attribute has been derived from Ordnance Survey’s imagery and Digital Surface Model (DSM). An Automatic Feature Extraction algorithm has extracted the various aspect values. This enhancement provides eight new attributes, which contain the sum roof area in m2 which face in each direction, which indicate the general shape characteristic of the roof. * ‘roofshapeapspect\_areainderterminable\_m2’ is the sum of all roof face areas that have been unable to be calculated (for example, obscured by vegetation). * ‘roofshapeaspect\_areatotal\_m2’ is the sum of all roof areas, excluding those with indeterminable aspects. * ‘roofshapeaspect\_confidenceindicator’ is an attribute that indicates the quality of the data. These provide context on factors at time of capture which could have influenced the confidence in the data. The scope is all buildings > 4m2 than are in OS topographic data. However, this is subject to the availability of imagery and height models.

Map of Buildings styled by Roof Aspect — Buildings styled by Roof Aspect

## Physical State Physical State is a new attribute that applies to “Building” Features (whilst Operational Status applies to “Building Part” Features) It describes the physical condition or structural state of the building {% tabs %} {% tab title="Under Construction" %} Under Construction: The building is currently being developed or being built

{% endtab %} {% tab title="Built" %} Built: The building is fully constructed and in a usable state

{% endtab %} {% tab title="Derelict" %} Derelict: The building is in a state of decay but retains most, or all, of its roof. Or the building is contained within a site that has fallen into a visible state of dereliction

{% endtab %} {% endtabs %} ## Phyisical State Attributes * ‘physicalstate’ defines the state of the building in relation to its physical condition * ‘physicalstate\_updatedate’ defines the date when the phyical state was last updated

Map and attribution of a building highlighting the physical state attributes

### Building lifecycle All buildings are within scope to receive a Physical State value, however, not every building will be recorded as “Under Construction” during its lifecycle. For example: a newly built shed in a private garden may not be captured during construction. ### Derelict buildings Our data is driven by change intelligence, and while we do capture most instances of properties falling into disuse, not all derelict buildings will be captured in our data because we might miss, for example, where a residential property falls into disuse. Derelict buildings are determined to be ruined structures with a roof – buildings with boarded up windows will not be classified as “Derelict” and will instead be classified as “Built”. It is worth noting that Physical State is not a direct indicator of building occupancy ## Where has the Phyisical State data come from? Physical State is derived from OS topographic data capture. This includes information associated with the Building feature and information associated with the Land Use Sites feature. Maintenance delivered through: * Interpretation of OS topographic data and aerial imagery * Ongoing maintenance is through ground survey

Map of buildings styled by physical state

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