[Talk-GB] UK cycle route: NCN National Route 17 (21895) in Kent

Sat Jan 15 14:39:29 UTC 2022

For the rest of us, the OSM Relation Analyser is pretty good at showing any
gaps in relations:
http://ra.osmsurround.org/analyzeRelation?relationId=21895&noCache=true&_noCache=on

Regards,
_Paul_

On Fri, 14 Jan 2022, 18:17 Dave F via Talk-GB, <talk-gb at openstreetmap.org>
wrote:

> I've tweaked it a bit further using this XML/XSLT/XPath parser to search
> for gaps & spurious spurs:
>
> Download the route relation as OSM/XML data
>      curl -o NCN_17.osm -g
> https://overpass-api.de/api/interpreter?data=rel(id:21895);(._;>;);out;
>
> Parse the data & output the results to file:
>      java -jar C:\<Path to program>\SaxonHE9-7-0-2J\saxon9he.jar
> -s:NCN_17.osm -xsl:Route_Rel_Check.xsl -o:Route_Rel_Check_Upload.osm
>
> The XSL routine that performs the parsing, Basically it takes the first
> node of each way & compares it with the end node of all the other
> ways.If it doesn't find a match it outputs the node's id.
> The list of nodes starting with ' [not(@ref' are genuine end nodes to be
> ignored, such as the start/end nodes & where ways meet roundabouts
> mapped as a singular, circular way:
>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
> version="2.0">
>    <xsl:output omit-xml-declaration="yes" indent="yes" />
>    <xsl:strip-space elements="*" />
>    <xsl:template match="osm">
>              <xsl:for-each-group select="way/nd[position() = (1,
> last())]" group-by="@ref">
>                  <xsl:sequence select=".[not(current-group()[2])]
> [not(@ref ='26908253' or @ref='269810730' or @ref='30394554' or
> @ref='33118766' or @ref='30394555')]"/>
>              </xsl:for-each-group>
>    </xsl:template>
> </xsl:stylesheet>
>
> I've find this routine very useful to maintain cycle route relations in
> my area
> Others may find this helpful all types of route relations.
>
> DaveF
>
> On 14/01/2022 15:46, Gregory Williams wrote:
> > I've subsequently conversed with a Sustrans Volunteer Ranger that I
> > know in the area and have cleared up the relation further. It should be
> > looking better now.
> >
> > Gregory
> >
> > On Fri, 2022-01-14 at 08:28 +0000, Gregory Williams wrote:
> >> I put some of that NCR17 mapping in. NCR17 has changed alignment over
> >> time, but has also had issues with bad signing.
> >>
> >> I've removed some bits that I know are now wrong. I suspect that the
> >> portion in west Maidstone around Poplar Grove to Queen's Road is also
> >> wrong, but I think that there have been odd signs here that
> >> incorrectly
> >> suggest that it is NCR17. I seem to recall Maidstone having some
> >> signs
> >> that confused "17" and "(17)". I.e. is *on* vs. *leads to* NCR17.
> >>
> >> I've copied Maidstone Cycle Forum, as they should be know their patch
> >> better than me! Perhaps they may be able to advise about the Medway
> >> portion too?
> >>
> >> Gregory
> >>
> >> On Thu, 2022-01-13 at 13:28 +0000, Chris Hodges wrote:
> >>> I'm not local so can't comment on that specific route, but it is
> >>> plausible for a few reasons:
> >>>
> >>> - Some routes really do start and stop in silly places because land
> >>> access negotiations have stalled. Sometimes in multiple places.
> >>> NCN33
> >>> in Somerset is like that, with work finally beginning on connecting
> >>> it
> >>> to NCN26 and Clevedon after over 10 years of proposals and talk.
> >>>
> >>> - Sustrans have been removing branding on (and support for) routes
> >>> that
> >>> don't fit their rather arbitrary standards.  This can leave gaps -
> >>> or
> >>> sections that have NCN numbers but aren't put of the NCN (according
> >>> to
> >>> their own map https://explore.osmaps.com/ncn hosted by OS which I
> >>> used
> >>> to use as part of my route planning but don't trust)
> >>>
> >>> - That same map doesn't always reflect reality as it ever happened,
> >>> nor
> >>> does it match the signs, which also don't match reality. We can and
> >>> do
> >>> make a better job of it in places.
> >>>
> >>> For example  NCN 45 into Bridgnorth from the north is correctly
> >>> mapped
> >>> on OSM (following the signs with a little interpolation where
> >>> they're
> >>> missing)
> >>>
> https://www.openstreetmap.org/search?query=bridgnorth#map=14/52.5333/-2.4153&layers=C
> >>>
> >>> but some odd sections that don't join up with anything are also
> >>> mapped.
> >>> They match Sustrans's own mapping, except that OSM is more sensible
> >>> and
> >>> doesn't show a route going across a school playing field, near but
> >>> not
> >>> following a public footpath. Some signs exist on those disconnected
> >>> sections.  I think they had NCN route numbers on them when I was
> >>> there,
> >>> but I've also seen route numbers covered up
> >>>
> >>>
> >>> A glance at Sustrans's map of the Maidstone area, without detailed
> >>> inspection, suggests that much of what looks wrong could be right
> >>> or
> >>> at
> >>> least official, but not all the disconnected sections match that
> >>> map.
> >>> But I wouldn't trust it to be right, as well as the obvious
> >>> licensing
> >>> block on the data, i.e. even if it was allowed, copying the
> >>> "official"
> >>> data would increase the errors
> >>>
> >>>
> >>> Chris
> >>>
> >>>
> >>> On 13/01/2022 11:24, Andy Townsend wrote:
> >>>> This seems a bit odd:
> >>>>
> >>>> https://www.openstreetmap.org/relation/21895
> >>>>
> >>>> shows a couple of disconnected sections around Maidstone and an
> >>>> odd
> >>>> spur towards Chatham.
> >>>>
> >>>> https://osm.mapki.com/history/relation/21895
> >>>>
> >>>> suggests that at least one of the Maidstone "extras" has been
> >>>> there
> >>>> since 2008, suggesting that it's not a recent faux pas.
> >>>>
> >>>> I suspect that given the number of avid cyclists on this list
> >>>> that
> >>>> someone will be immediately able to say "actually that's wrong"
> >>>> or
> >>>> "actually, that's correct because..."
> >>>>
> >>>> Best Regards,
> >>>>
> >>>> Andy
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
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> >>>
> >>>
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