[Talk-GB] [talk-gb] National Cycle Network removal/reclassification

Richard Fairhurst richard at systemed.net
Sun Aug 16 17:16:21 UTC 2020


Robert Whittaker wrote:
> Sustrans' NCN data is available from
> http://livingatlas-dcdev.opendata.arcgis.com/datasets/54a66fa3c15d4e118e085fbd9b141aae
> as vector tiles under the ODbL. However, note that the "removed"
> sections mostly won't be reflected on the ground yet. Also, the
> dataset isn't perfect, as there's at least one bit near me where
> the route Sustrans have is wrong. I think it's also likely that
> some of the small gaps that have been created are inadvertent and
> will quickly be filled back in as volunteers review the new network.

It's in friendlier formats at https://data-sustrans-uk.opendata.arcgis.com
:)

Many of the changes are fairly unambiguous and could be made directly
using this data as a guide. For example, the Wiltshire Cycleway is no
longer NCN 254, so can be changed to network=rcn and the ref= tag
removed. The parts of NCN 20 between Crawley and the outskirts of
Brighton can be removed entirely from the relation. And so on.

There are a few cases where it's not immediately clear what will
happen to the route - in Shropshire, for example, where several routes
are being reclassified or removed. In these cases then we can probably
make tentative changes but will need to keep an eye on the ground for
signage to see the future fate of both these routes and other nearby
ones (which might be renumbered?). And, as you say, there may be
some small gaps that have inadvertently arisen.

I would also encourage people to look carefully at the sections that
are being removed, and consider whether the way tagging is appropriate.
It's plausible that there are some highway=unclassifieds in there that
would better be highway=tertiary. It would also often be helpful to
add a lanes= tag.

> We also might need to think about our tagging, as there will now be
> more levels of routes: Full NCN routes, other promoted named routes
> that aren't on the NCN. How can we distinguish these in OSM?

Precedent is generally that non-Sustrans routes are network=rcn, even
long-distance ones like the National Byway. I'd suggest we continue to
follow this for most redesignated routes. The alternative would be to
retain as network=ncn and make use of the operator= tag, but (being
blunt) this will probably not be understood by most mappers apart from
the small hard core of us who really care about cycle route designation,
so it will be broken repeatedly and end up as a maintenance burden.

One slight nuance is what we do about redesignated sections of a long-
distance cycle route. For example, Hartside will no longer be part of
NCN 7 or NCN 68, but will continue to be part of the C2C and Pennine
Cycleway. The answer is probably to maintain two separate relations,
which is a bit of a maintenance faff but at least understandable.

Richard
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