Metadata and licences

Why metadata matters

Metadata is data about data. In a National Access Point it is the catalogue entry that lets users find a dataset and judge whether it fits their needs, without opening the file.

What good metadata includes

• Title and description in clear language.
• Owner or publisher and a contact for questions and error reports.
• Coverage: geographic area and modes of transport.
• Format and version, for example NeTEx with a given profile. See data formats.
• Update frequency and the date of the latest update.
• Access: download link or API endpoint, and whether an account is needed.
• Licence and attribution requirements.
• Quality information, where available.

Catalogues are often built on shared vocabularies such as DCAT, which is also what makes it possible to harvest datasets into larger catalogues like the European data portal.

What a licence does

A licence states what users may do with the data: copy it, adapt it, use it commercially, and what they must do in return, such as give attribution. Without a clear licence, many users will not dare to reuse the data.

Examples of licences

Common examples used for open data include:

• CC0 1.0: public-domain dedication, no conditions.
• CC BY 4.0: free reuse with attribution.
• ODbL: open database licence with attribution and share-alike conditions.
• National open licences: for example the Norwegian Licence for Open Data (NLOD), the French Open Licence (Licence Ouverte) and the Data licence Germany.

Which licences a NAP accepts, and whether data must be open at all, depends on national rules and on the dataset. Check the metadata and the NAP's own guidance.

Tips

• Use one clear licence per dataset and state it in the metadata, not only in a separate document.
• Say how attribution should be written.
• Keep metadata up to date when the data or its access changes.

See also how to publish transport data and how to use transport data.

Frequently asked questions