> 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/land-and-terrain-portfolio/os-mastermap-sites-layer/os-mastermap-sites-layer-overview/product-supply.md).

# Product supply

### Available formats <a href="#bookmark20" id="bookmark20"></a>

OS MasterMap Sites Layer is supplied in three different formats:

* Geography Markup Language (GML) 3.2.1
* GeoPackage
* Vector tiles (MBTiles)

### Product supply mechanism <a href="#bookmark21" id="bookmark21"></a>

OS MasterMap Sites Layer incorporates a web-based ordering system that allows customers to order their initial data supply and any updates, obtain price estimates and view details of their holdings on demand. The product is supplied as an online download. You can download data in various formats from the [OS Data Hub](https://osdatahub.os.uk/).

### Coverage and file sizes <a href="#bookmark22" id="bookmark22"></a>

For GML, OS MasterMap Sites Layer is a national dataset and is maintained and supplied as 5km² tiles of data via Area of Interest (AOI) supply or as Great Britain (GB) supply. File size estimates can vary from about 2 KB compressed to about 162 KB (compressed) for tile supply. A full GB supply will be approximately 43 MB compressed. Compression rates vary and are dependent on the size and content of a tile.

For GeoPackage and vector tiles, the coverage will be GB supply only. The file size is approximately 90 MB zipped for GeoPackage, and 160 MB zipped for vector tiles.

### Change-only updates <a href="#bookmark23" id="bookmark23"></a>

Change-only updates (COU) are not available for OS MasterMap Sites Layer.


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