> 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/land-and-terrain-portfolio/os-terrain-50/os-terrain-50-technical-specification/geopackage.md).

# GeoPackage

OS Terrain 50 contours are supplied as a national GeoPackage file.

GeoPackage offers users the following benefits:

* The single file is easy to transfer and offers the end-user a rich experience.
* Attribute names are not limited in length, making the format user-friendly.
* The file size limit is very large at 140 TB (a file size limit might be imposed by the file system to which the file is written).
* It supports raster, vector and database formats, making it a highly versatile solution.

For general guidance on using the product in GeoPackage format, please see the [Getting started with GeoPackage guide](/os-downloads/resources/product-resources/getting-started-with-geopackage-and-vector-tiles-guides/getting-started-with-geopackage.md).

### Data structure <a href="#bookmark24" id="bookmark24"></a>

The names of the GeoPackage layers in the OS Terrain 50 contour supply are outlined in the following table.

| Layer name            |
| --------------------- |
| spot\_height          |
| land\_water\_boundary |
| contour\_line         |

### Attribute naming format comparison <a href="#bookmark25" id="bookmark25"></a>

The naming of attributes has been updated in accordance with guidelines to make them more user friendly.

| 2022 GPK Attribute name | 2023 GPK Attribute name |
| ----------------------- | ----------------------- |
| Fid                     | fid                     |
| Id                      | id                      |
| propertyValue           | property\_value         |
| propertyValue\_uom      | N/A                     |
| spotHeightType          | spot\_height\_type      |
| waterLevelCategory      | water\_level\_category  |
| contourLineType         | contour\_line\_type     |


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