[Talk-GB] Composite mapping (OSM and OS, PRoWs etc)

Robert Whittaker (OSM lists) robert.whittaker+osm at gmail.com
Fri Sep 9 08:04:29 UTC 2016

On 8 September 2016 at 20:56, Dudley Ibbett <dudleyibbett at hotmail.com> wrote:
> If a footpath isn’t accessible by a walker then I don’t generally put it on
> OSM or I will end it at the obstruction.  It looks like you are treating
> this as incomplete data and filling in the footpath according to the
> published PROW data.  Perhaps we need some way of tagging/putting these ways
> in OSM so they can potentially be eliminated when rendering a map that is
> designed to reflect footpaths that are accessible to walkers.

What I do in this case -- where I know where a PRoW route should go
from the Council data, and have surveyed it and found it inaccessible
-- is to add a way with appropriate designation=*, prow_ref=*, and
access tags (e.g. foot=designated), but also add highway=no and a
note=* to explain the situation. I believe this tagging is technically
accurate, as the mode-based access tags are supposed to be for legal,
rather than physical, access rights. However, the physical
inaccessibility isn't tagged explicitly in this scheme, and it would
be interesting to know what routers make of highway=no. (The
highway=no is used, as opposed to just not having a highway=* tag,
since a missing highway tag could arise from mapper error or because
the route hasn't been surveyed yet.)

I had a look to see if there were any physical equivalents of the
mode-based access tags (e.g. foot:physical=*, to mirror
maxheight:physical) but there didn't seem to be anything in use. I
haven't been using these tags so far, but perhaps it would be a good
idea to start. So for e.g. a Bridleway that's blocked by a hedge, you
could tag the short section through the hedge that's blocked as

prow_ref=Trumpton BR 5
note=Definitive line of PRoW but route here is completely blocked by hedge.

If the parts on either side of the hedge are accessible, then they can
be tagged as normal. If there's a in-use unofficial diversion, I'd tag
that with appropriate highway and access tags. (My understanding is
that legally you're allowed to circumnavigate any PRoW obstructions by
using a reasonable alternative on the same owner's land.)

Best wishes,


Robert Whittaker

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