> 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/buildings-and-infrastructure-portfolio/os-mastermap-topography-layer-building-height-attribute/os-mastermap-topography-layer-building-height-attribute-getting-started-guide/what-do-i-need-to-use-this-data.md).

# What do I need to use this data?

OS MasterMap Topography Layer – Building Height Attribute is designed to be joined to and then used as part of the OS MasterMap Topography Layer. The guide on [joining data to a OS MasterMap Topography Layer](/os-downloads/products/buildings-and-infrastructure-portfolio/os-mastermap-topography-layer-building-height-attribute/os-mastermap-topography-layer-building-height-attribute-getting-started-guide/joining-building-height-attribute-data-to-a-os-mastermap-topography-layer.md) gives guidance on how to join this data to your Topography Layer holding.

As it is a part of the OS MasterMap Topography Layer, Building Height Attribute is designed for use in a digital map within geographic information systems (GIS) and database systems. For details of Ordnance Survey’s Licensed Partners who can assist you with incorporating Building Height Attribute data in their systems, please see the [software for mapping page on the OS website](https://www.ordnancesurvey.co.uk/business-government/tools-support/gis/software).

Ordnance Survey does not recommend either suppliers or software products as the most appropriate system will depend on many factors, such as the amount of data being taken, resources available within the organisation, the existing and planned information technology infrastructure and last but by no means least, the applications that the data will be used for. However, as a minimum, the following elements will be required in any system:

* A means of reading the data, either in its native format or by translating it into a file format or for storage in a database.
* A means of storing and distributing the data, perhaps in a database or through a web-based service.
* A way of visualising and / or querying the data, typically a GIS.

## Backup provision of the product <a href="#id-2.2-backup-provision-of-the-product" id="id-2.2-backup-provision-of-the-product"></a>

You are advised to copy the supplied data to a backup medium before following the steps in this guide.

## Typical data volumes for the product <a href="#id-2.3-typical-data-volumes-for-the-product" id="id-2.3-typical-data-volumes-for-the-product"></a>

For reading purposes, it is recommended that users store the data on a single hard disc as this will speed up the ability of your computer to read the data. The uncompressed file size for the full supply of Great Britain (GB) is 2.6Gb.


---

# 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/buildings-and-infrastructure-portfolio/os-mastermap-topography-layer-building-height-attribute/os-mastermap-topography-layer-building-height-attribute-getting-started-guide/what-do-i-need-to-use-this-data.md?ask=<question>&goal=<endgoal>
```

`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.