# Page Not Found

The URL `height-and-imagery/os-terrain-5/os-terrain-5-overview/the-national-grid` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [The National Grid](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-overview/the-national-grid.md)
- [National Grid](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/miniscale/miniscale-technical-specification/national-grid.md)
- [Pre-requisites](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-overview/pre-requisites.md)
- [Data structure](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-overview/data-structure.md)
- [OS Terrain 5 Technical Specification](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-technical-specification.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-overview/the-national-grid.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.

### Option 2 — Browse the documentation index

Full index: https://docs.os.uk/os-downloads/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://docs.os.uk/os-downloads/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/os-downloads/products/land-and-terrain-portfolio/os-terrain-5/os-terrain-5-overview/the-national-grid.md`).

You may also use `Accept: text/markdown` header for content negotiation.