# OS NGD Fundamentals

## Introduction

The following pages provide an overview of the OS National Geographic Database (OS NGD); they cover the core elements of its design, including data formats, the coordinate reference systems used, and how Change-Only Updates (COUs) will be provided, amongst other topics:

* [Terminology and access](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/terminology-and-access)
* [File formats and naming](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/file-formats-and-naming)
* [Data ordering and currency](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/os-ngd-data-ordering-and-currency)
* [COU supplies](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/cou-supplies)
* [Data schema versioning](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/data-schema-versioning)
* [Unique identifiers](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/unique-identifiers)
* [Coordinate reference systems](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/coordinate-reference-systems)
* [Attribute information for feature types](https://docs.os.uk/osngd/getting-started/os-ngd-fundamentals/attribute-information-for-feature-types)

{% hint style="info" %}
These pages should be used in conjunction with the more detailed pages available within the [Data Structure section](https://docs.os.uk/osngd/data-structure/data-structure-information) which are specifically focussed on the different OS NGD themes, collections and feature types.
{% endhint %}

***

## Discover OS NGD

Detailed documentation on OS NGD design and practical guides on how to apply OS NGD data:

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f4d6">📖</span> OS NGD Explained</h3><p>A high level summary of what the OS NGD is, how to access it and who can use it.</p></td><td></td><td><a href="../introduction-to-os-ngd/os-ngd-explained">os-ngd-explained</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="2753">❓</span> FAQs</h3><p>Frequently asked questions on OS NGD data and access methods (OS Select+Build and OS NGD APIs).</p></td><td></td><td><a href="faqs">faqs</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f469-1f3eb">👩‍🏫</span> OS NGD Webinars, Tutorials and Case Studies</h3></td><td>Learn more about the OS NGD through our webinars and tutorials. Case studies demonstrate how customers across numerous sectors are already using and benefiting from OS NGD data.</td><td><a href="os-ngd-talks-webinars-tutorial-videos-and-case-studies">os-ngd-talks-webinars-tutorial-videos-and-case-studies</a></td></tr></tbody></table>

## Explore OS NGD

In-depth information on OS NGD data, including structure, applications and news:

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f4e3">📣</span> OS NGD News</h3></td><td>Learn about new data enhancements and service updates released for the OS NGD.</td><td><a href="../os-ngd-news">os-ngd-news</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f5c3">🗃️</span> Data Structure</h3></td><td>Data structure pages provide more detailed information about data available for OS NGD themes, collections and feature types.</td><td><a href="../data-structure/data-structure-information">data-structure-information</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f3a8">🎨</span> Styling OS NGD Data</h3></td><td>Resources for styling OS NGD data.</td><td><a href="styling-os-ngd-data">styling-os-ngd-data</a></td></tr></tbody></table>

## Get OS NGD

Try out OS NGD sample data, download it via OS Select+Build or access it through the OS NGD APIs:

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f5fa">🗺️</span> OS NGD Sample Data</h3></td><td>Try out OS NGD by downloading an area of sample data or visualising it online.</td><td><a href="../introduction-to-os-ngd/os-ngd-sample-data">os-ngd-sample-data</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f4e5">📥</span> OS Select+Build</h3></td><td>Download OS NGD data using our bespoke download service, OS Select+Build.</td><td><a href="downloading-with-os-select+build">downloading-with-os-select+build</a></td></tr><tr><td><h3><span data-gb-custom-inline data-tag="emoji" data-code="1f4cc">📌</span> OS NGD APIs</h3></td><td>Access OS NGD data using the OS NGD APIs to get started using OS NGD within desktop, web and mobile applications.</td><td><a href="access-the-os-ngd-api">access-the-os-ngd-api</a></td></tr></tbody></table>