Standards & licences (in this atlas)

The Standards section of this atlas answers a narrow, practical question: which formats, protocols and open-data licences do the documented projects actually run on, and which cities run each one. That layer decides whether a city's data can be read by anyone but its vendor, whether its trains can be resignalled by anyone but their supplier, and whether its open data is open in any sense a reuser would recognise.

Membership is derived, not asserted: an entry appears under a standard because its own record names it. Every match prints the sentence it was found in, because a derived membership has exactly one failure mode — an abbreviation that means something else in that entry — and showing the sentence puts that in front of the reader instead of hiding it behind a count.

The most-used part is the open-data licence ladder, ordered from most to least permissive. Who stands on each rung is computed from the entries; the order of the rungs is an editorial judgement kept in a reviewable file.

One thing this is not: the atlas's own rules for grading and publishing. Those are the Evidence Constitution — the footer row now reads How we grade evidence so the two can no longer be mistaken for each other.