> 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/code-point-technical-specification/product-structure.md).
# Product structure
### Attributes
| 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. |
| PO Box indicator | Denotes if the postcode is a PO Box. |
| Total delivery points | The total number of both matched and unmatched delivery points in the postcode. Not in BT data for Northern Ireland. |
| Delivery points | Number of matched addresses in the postcode unit that have a PQI of 10 or 20. Not in BT data for Northern Ireland. |
| Domestic delivery points | Number of non PO box delivery points that have no PAF organisation name. Not in BT data for Northern Ireland. |
| Non domestic delivery | Number of non PO box delivery points that have a PAF organisation name. Not in BT data for Northern Ireland. |
| PO Box domestic delivery points | Number of PO Box delivery points. Not in BT data for Northern Ireland or where PQI is 20 in Scotland. |
| Matched addressed premises | Number of delivery points in buildings or building subdivisions, after exclusion of duplicated coordinate pairs. Not in BT data for Northern Ireland or where PQI is 20 in Scotland. |
| Unmatched delivery points | Number of delivery points awaiting improvement on location. Not in BT data for Northern Ireland or where PQI is 20 in Scotland. |
| Easting | Distance in metres east of National Grid origin. |
| Northing | Distance in metres north of National Grid origin. |
| Country code | Code used by ONS to identify the country in which the Code Point georeferenced coordinates lies. |
| NHS regional health authority code | English Pan Strategic Health Authority in which 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. |
| Postcode type | Indicates whether the user is large, L, or small, S. Large postcode type users receive more than 500 pieces of mail. Small users receive 70 pieces per day. |
Each postcode unit location – also known as CPLC (Code-Point Location Co-ordinate) – 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 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 (or Land & Property Services for the BT postcode area only). |
| 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
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## 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, and the optional `goal` query parameter:
```
GET https://docs.os.uk/os-downloads/products/areas-and-zones-portfolio/code-point/code-point-technical-specification/product-structure.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
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.