> 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-greenspace-layer/os-mastermap-greenspace-layer-technical-specification/os-open-greenspace-lookup-table.md).

# OS Open Greenspace lookup table

OS has published two related products on greenspaces, OS Open Greenspace and [OS MasterMap Greenspace Layer](/os-downloads/products/land-and-terrain-portfolio/os-mastermap-greenspace-layer.md). For some applications, it is intended that these products are used together as they contain different information.

OS Open Greenspace is part of Ordnance Survey’s Open Data portfolio and depicts the location and extent of exercise and recreation facilities likely to be open to the public. It includes access points locating entrances and exits from greenspace sites and proper names. Full information regarding OS Open Greenspace can be found in the [technical specification](/os-downloads/products/land-and-terrain-portfolio/os-open-greenspace/os-open-greenspace-technical-specification.md).

A lookup table exists to link between the two products. Where an OS Open Greenspace polygon and an OS MasterMap Greenspace Layer polygon exist in the same location, the lookup table provides this information. This can be used to join the two products together, where appropriate, if the user wishes to use both datasets. OS MasterMap Greenspace Layer and OS Open Greenspace will be maintained and released with the same currency to ensure that these datasets are synchronised, allowing them to be easily used together.

Records will only be included in the lookup file where an appropriate match between an OS MasterMap Greenspace Layer TOID and OS Open Greenspace ID can be made.

## Format <a href="#id-3.2-format" id="id-3.2-format"></a>

The lookup table is provided as a comma-separated value (.csv) file. The file will be supplied with headers and the information contained is detailed in the attributes above. It will only be supplied to customers taking full Great Britain (GB) supply of OS MasterMap Greenspace Layer. If you are taking AOI supply and would like access to the lookup table, please contact the customer service centre (<CustomerServices@os.uk>) to request this. Please note that as the Lookup Table is only generated for full GB supply, there will be additional records within the table that won't match-up with an AOI data supply – these additional records exist outside your AOI and should be ignored.

## Attributes

### TOID

The OS MasterMap Greenspace Layer TOID.

### GREENSPACESITEID

The OS Open Greenspace ID for a polygon which intersects with the relevant TOID.


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