> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/buildings-and-infrastructure-portfolio/os-mastermap-topography-layer-building-height-attribute/os-mastermap-topography-layer-building-height-attribute-overview/product-supply-information.md).

# Product supply information

## Product supply format <a href="#bookmark14" id="bookmark14"></a>

Building Height Attribute data is supplied in comma-separated values (CSV) file format. Files will not be compressed.

Data will be refreshed every six months.

## Product supply mechanism <a href="#bookmark15" id="bookmark15"></a>

OS MasterMap Topography Layer – Building Height Attribute is supplied as an online download. You can download data in CSV format from the [OS Data Hub](https://osdatahub.os.uk/).

The product is currently still available for customers to request through [OS Orders](https://orders.ordnancesurvey.co.uk/sso/login.shtml).

## Coverage and file sizes <a href="#bookmark16" id="bookmark16"></a>

OS MasterMap Topography Layer – Building Height Attribute data will be supplied in 5 km tiles. Data will be uncompressed and file sizes will vary significantly depending on the number of buildings and structures contained within the 5 km² area. For customers with a full holding of OS MasterMap Topography Layer, a full Great Britain (GB) set is also available. For those customers who do not have a full OS MasterMap Topography Layer supply, only tiles that intersect OS MasterMap Topography Layer holdings may be downloaded.

<figure><img src="/files/Zq84jGfL3Kjc88CXEVeS" alt="Illustration of the data download structure. The file path for downloading the 5x5km tiles is BLDHDL > Data > Excel spreadsheets named SP2575 and SP2580. The file path for downloading the GB National Set is BLDHGB > bldhgb_csv.zip > Data > Excel spreadsheets named SP2575 and SP2580." width="563"><figcaption><p><em>Illustration of the data download structure.</em></p></figcaption></figure>

Each 5 km² tile will contain Building Height Attribute data for any building that is partly or wholly contained within that tile. As such, buildings that traverse tile boundaries will be duplicated in contiguous holdings.


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