While field-testing an app I’m building for walking Public Rights of Way (MOROW), I found a real one. Chippenham parish path CHIP108, a legally recorded Byway Open to All Traffic, was mapped in OSM with highway=bridleway, ref=CHIP108, and a free-text note describing its BOAT status, but no designation= and no prow_ref=. Those are the two tags any PRoW-aware tool actually reads, so the path was rendering as an ordinary, unremarkable line. I fixed that one way directly (changeset 185555601), but the obvious next question was whether the same mistake, recording a council’s path reference under the generic ref= tag instead of prow_ref=, is a one-off or systematic.

Before building anything to find out, I went looking for prior art, and found it. Robert Whittaker’s UK PRoW toolkit (https://osm.mathmos.net/prow/) already does this properly, county by county, comparing OSM against official Definitive Map data and generating per-parish tagging-error reports with real way IDs ready to work through. For Wiltshire alone: 8,354 recorded rights of way, only 58% carrying designation=, only 24% carrying prow_ref=. That’s roughly 4,450 km of Wiltshire’s legal PRoW network without a prow_ref tag, a scale question the tool had already answered, far beyond anything I’d have worked out from scratch.

CHIP108 itself doesn’t appear on either of Wiltshire’s error lists, most likely because the detection starts from ways already carrying some PRoW tag and checks the other; CHIP108 had neither. I’ve asked on Robert’s forum thread (https://community.openstreetmap.org/t/roberts-openstreetmap- stuff-osm-mathmos-net/112981) whether that’s a known gap or something worth extending for.

Testing the fix workflow

Rather than wait indefinitely for a reply, I pulled a small sample, 8 ways from Wiltshire’s live tagging-errors page, and hand-verified each one against Wiltshire Council’s official Open Data Hub PRoW dataset (a genuinely open, OGL3-licensed ArcGIS feature service, distinct from their proprietary interactive map viewer) before touching anything.

Worth sharing because the verification step earned its keep, not just rubber-stamped the list: - One way already had the correct designation tag; the “error” only needed the missing prow_ref. - One reference number turned out to cover both a footpath and a bridleway segment under the same prow_ref. The physical way’s tags (foot/bicycle/horse access) were needed to work out which one it actually was. - Two of the eight sit in a different parish to the one Robert’s tool assigned them, which matches his own documented bounding-box-vs-parish caveat rather than being a bug. - Two candidates couldn’t be confirmed with confidence at all, and are being held back rather than guessed at.

Robert’s own tagging-error pages already warn that some flagged ways aren’t genuine errors. This is what that looks like in practice.

A wider gap: which UK councils actually publish this openly?

Chasing down Wiltshire’s specific feed led to a broader question: how many of England and Wales’s 161 Rights of Way authorities actually publish their Definitive Map data under an open licence? Robert maintains a thorough catalogue (https://osm.mathmos.net/prow/open-data/) of exactly this, which I used as the baseline rather than starting fresh.

The numbers are striking. 90.7% of authorities already have some kind of online interactive Rights of Way map for the public, so the underlying data clearly exists digitally in almost every case, but only 32.9% have released it under an open licence for reuse. That’s a two-thirds gap between “we’ve digitised this” and “you can actually use it.”

Searching for live ArcGIS-hosted feature services (the same pattern behind Wiltshire’s feed) against councils Robert’s catalogue currently shows as having no data on record turned up several genuinely new, properly OGL-licensed sources: Durham, North East Lincolnshire, and Redcar and Cleveland among them, plus a much fresher live source for Lincolnshire than the 22-month-old FOI-sourced snapshot currently on file. I’ll be passing these on.

I’ve also started emailing a small pilot batch of councils that already publish an online map but haven’t opened the underlying data, pointing out (with the actual comparable-authority numbers) that the extra step to an open licence is usually small. Early days, but happy to share how it goes and the approach used, if it’s useful to others chasing the same gap elsewhere.

Thanks

None of the harder parts of this were mine to solve. Robert Whittaker’s tooling and open-data cataloguing did the heavy lifting. This is really just a small addition at the edges: a workflow for hand-verifying a batch of fixes carefully, and a fresh pass at which councils have quietly opened up their data since the catalogue was last checked.

If you maintain, or know someone who maintains, Rights of Way data for a UK council not yet on Robert’s list, get in touch with him, or with me.

Chris