> For the complete documentation index, see [llms.txt](https://docs.os.uk/osngd/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/osngd/getting-started/os-ngd-fundamentals/attribute-information-for-feature-types.md).

# Attribute information for feature types

On the feature type pages (which are located in the [Data Structure section](/osngd/data-structure/data-structure-information.md)), the following information can be found about each attribute:

* **Name and Definition**: The name of the attribute and what it is describing.
* **Data Types**: The values the attribute can take. For example, a numeric value or a string. This is provided for all three data formats – GeoJSON, GeoPackage, and CSV.
* **Nullable:** A True or False value to denote whether the attribute always has to be populated with a value (False) or can be NULL (True).
* **Code List Name**: The name of the code list used in association with the attribute (if applicable) and a hyperlink to the page displaying that code list.
* **Max Length**: Values are given here to indicate the maximum length that you will find in the attribute, to aid in developing applications.
* **Multiplicity**: Describes how many times this value is expected to be populated in the data. These values may be used in combination.
  * 1: There must be a value.
  * 2: There must be two values.
  * n: There may be one or more values.
  * 0: Population is optional.
* **OS NGD API – Features Filterable**: A Yes / No value to denote whether you can refine your query in OS NGD API – Features specifically on this attribute.
* **OS Select+Build Filterable**: A Yes / No value to denote whether you can refine your order in OS Select+Build on this attribute.
* **Data Schema Version**: The OS NGD schema version the data above applies to. Please note that concurrent schema versions may be available at one time. For more information on how data schema versioning works in the OS NGD, please refer to the [Data schema versioning page](/osngd/getting-started/os-ngd-fundamentals/data-schema-versioning.md).


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