> 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/areas-and-zones-portfolio/code-point-open/code-point-open-technical-specification/product-structure.md).

# Product structure

## Attributes <a href="#bookmark2" id="bookmark2"></a>

| Attribute                          | Description                                                                                                                                |
| ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
| Postcode                           | Contains elements for postal area, district, sector, and unit.                                                                             |
| Positional quality indicator (PQI) | A flag used to indicate the positional accuracy of the coordinates allocated to each postcode record.                                      |
| Easting                            | Distance in metres east of National Grid origin.                                                                                           |
| Northing                           | Distance in metres north of National Grid origin.                                                                                          |
| Country code                       | Code used by the Office for National Statistics (ONS) to identify the country in which the Code-Point Open georeferenced coordinates lies. |
| NHS regional health authority code | English Pan Strategic Health Authority in which Code-Point Location Coordinate (CPLC) falls.                                               |
| NHS health authority code          | English Strategic Health Authority or Scottish Health Board in which CPLC falls.                                                           |
| Administrative county code\*       | County in which CPLC falls.                                                                                                                |
| Administrative district code\*     | Unitary Authority, Metropolitan and Non-Metropolitan District, London Borough, or Scottish Council Area in which CPLC falls.               |
| Administrative ward code\*         | Electoral Ward or Division in which CPLC falls.                                                                                            |

An asterisk (\*) indicates that the attribute is blank when the entity does not have a code. The Welsh Local Health Boards are included in Code-Point Open.

Each postcode unit location – also known as CPLC (Code-Point Location Coordinate) – is coordinated on the respective National Grid, with Eastings and Northings quoted to a resolution of 1m. The accuracy of each postcode unit coordinate pair is defined by the positional quality indicator (PQI), which provides a quality statement of that Code-Point Open record. There are seven PQI values for the positional quality:

| PQI | Description                                                                                                                               |
| --- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| 10  | Within the building of the matched address closest to the postcode mean determined automatically by Ordnance Survey.                      |
| 20  | As above but determined by visual inspection by National Records of Scotland (NRS).                                                       |
| 30  | Approximate to within 50m of the true position (postcodes relating to developing sites may be within 100m of true position).              |
| 40  | The mean of the positions of addresses previously matched in PALF but which have subsequently been deleted or recoded (very rarely used). |
| 50  | Estimated position based on surrounding postcode coordinates, usually to 100m resolution, but 10m in Scotland.                            |
| 60  | Postcode sector mean.                                                                                                                     |
| 90  | No coordinates available.                                                                                                                 |


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