# 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.                                                                                                                 |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.os.uk/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-technical-specification/product-structure.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.