> 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/maps-and-imagery-portfolio/os-vectormap-district/os-vectormap-district-overview/product-supply.md).
# Product supply
## **Available formats**
OS VectorMap District is available as:
* Vector: ESRI Shapefile with each tile dataset zipped using gzip.
* Raster: TIFF and compressed using LZW (Lemple-Ziv-Welch) compression.
* Data: GML v3.2. Simple Features and schema zipped as a single file using gzip.
## **Supply mechanism**
OS VectorMap District can be ordered from the [OS Data Hub](https://osdatahub.os.uk/data/downloads/open/VectorMapDistrict).
### **The National Grid coverage for OS VectorMap District**
Ordnance Survey divides Great Britain into squares 100km by 100km. Each of these squares has a unique two-letter reference, for example, TG in the diagram below.
OS VectorMap District vector format tiles are identified by quoting the National Grid reference of the south-west corner of the 100km² area they cover, for example TG.
To describe an OS VectorMap District raster format tile, which covers 10km by 10km, first add a two-digit reference to the 100km by 100km square reference, with the easting first followed by the northing, for example, TG23.
For additional information on how to use the National Grid, visit the Ordnance Survey website at:
{% embed url="" %}
National grid tiles shown against a background map of Great Britain
## **Coverage and file sizes**
* Coverage is England, Wales and Scotland.
### **Shapefile:**
* 55 tiles, each covering 100km x 100km comprise the national set.
* Each tile comprises a set of up to 24 Shapefiles.
* Each Shapefile holds a single feature type.
* Features within each Shapefile are cut into a 10km x 10km grid.
* Tile sizes range from 1 Mb to 697 zipped Mb.
* The data is not encrypted.
### **GML data:**
* 55 tiles, each covering 100km x 100km comprise the national set.
* Each 100km tile is split into 20km by 20km tiles (809 in total).
* Each tile comprises of up to 57 Feature Codes.
* Features that cross the grid line are split.
* Tile sizes range from 1 Mb to 347 Mb.
* The data is not encrypted.
### **TIFF:**
* 2863 tiles, each covering 10km x 10km comprise the national set.
* Tiles range from 2 Mb to 6.7 Mb.
## **Seamless data**
In the vector product features that cross tile edges are included in both tiles, represented as hairy tiles. This avoids the creation of invalid geometries by arbitrary cutting, and facilitates greater use of the data in analytical applications. All features have unique identifiers which can be used to remove duplicates across tile edges, if required.
Note that these identifiers will not be persisted or maintained between product releases.
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