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  • #47574
    karlchick
    Participant

    In my OS theme I am looking at providing an option to only highlight designated footpaths as footpaths (i.e. green dashes) and all other paths as plain paths (i.e. thin black dashes) – since this is how OS display them on their maps and it helps inform the walker about the “legal” status of the footpath, i.e. on an OS map all green dashed footpaths are legally accessible footpaths – and will be designated by sign posts (either finger posts or foot path badges nailed to style and fence posts).

    I expected that OSM tags foot=designated would correspond to this, but it does not… most footpaths are just tagged foot=yes.

    But then I discovered that there is a designation tag which can be set to many values, but the three in the title are the ones that seem to relate to public accessible footpaths. here is a link to an example:

    https://www.openstreetmap.org/way/30825288 (public_footpath)
    https://www.openstreetmap.org/way/36894513 (restricted_byway)

    I realise that this tag is largely limited to usage in England/Wales (about 80% of the tags in the world according to tag-info) but they are used significantly:
    public_footpath = 246,203 usages
    restricted_byway = 6864 usages
    permissive_footpath = 3656 usages

    At the moment the footpaths with designation set above are mostly tagged also as foot=yes.

    I saw that this tag was previously used in the tag transforming for cycle attributes: https://www.openandromaps.org/oam-forums/topic/uk-bridleway-rendering-for-bikes__trashed/page/2

    So, I am wondering if it would makes sense to map (tag-transform) the following tags like this for OAM:
    designation=public_footpath –> foot=ft_designated
    designation=restricted_byway –> foot=ft_designated
    Note: restricted in UK means they are still legally accessible (i.e. not private) and are also signposted — so are effectively also “designated”.
    designation=permissive_footpath –> foot=ft_permissive

    If you are wondering what I will do with the footpaths in towns that are also tagged as foot=ft_designation (usually because the tagger has seen signage for foot|cycle access) but are not really the same kind of thing as the public rights of way… well I am using the surface tag to render those with man made hard surfaces to look more like highway=pedestrian pathways and not as footpaths.

    On a similar topic, I am also wondering about the designation=public_bridleway – if this something that should contribute to highway=bridleway in someway (I haven’t checked usage yet)…

    #47577
    Tobias
    Keymaster

    You probably missed this post in the thread?
    https://www.openandromaps.org/oam-forums/topic/uk-bridleway-rendering-for-bikes__trashed/page/2#post-27254
    It should all be in the maps already.

    Developer of Elevate mapstyle

    #47578
    karlchick
    Participant

    So, according to that post, if a footpath has foot=yes, then the designation tag is ignored?!

    This seems wrong, foot=yes is the default tag setting for paths (at least in id editor). It so seems that footpaths created in the past used to default to foot=yes, but do now default to foot=designated. But with over 1/4 million footpaths already created, most seem to be set to foot=yes…

    Setting foot=ft_designated is a more specific tag value adding value/information.
    Why not set foot=ft_designated based on the designation tag? I.e. overriding the default foot=yes.

    I can’t see it impacting existing themes, they already have to deal with ft_designated. But while designation tag is ignored whe foot is set, there is no consistent value added, most footpaths will just remain foot=ft_yes.

    #47580
    Tobias
    Keymaster

    It makes sense to not overwrite existing tags, as you can only guess which is the right one. So if there are contradictions the tagging of the object should be corrected, it’s no good idea to do it automatically. We have this quite often with access tags, as these are often used in a wrong sense.

    In this case – if someone adds a designation=* it should also be mapped in the access tags, see here:
    https://wiki.openstreetmap.org/wiki/Access_provisions_in_the_United_Kingdom

    Developer of Elevate mapstyle

    #47582
    karlchick
    Participant

    I agree that modifying tags is a bad idea, but in this instance it seems there are two ways of tagging designated footpaths:

    1. Foot=designated
    2. Designation=public_footpath

    The second way is used mostly in england/Wales.

    The definitions in osm are reasonably consistent for both, footpaths are designated/signed for pedestrian use.

    Would changing Foot=yes to foot=ft_designated be an issue? Isn’t a foot=designated implicitly also a foot=yes?

    OAM currently only accepts a small fraction of these paths, ie those tagged with designation==* that have no foot tags set.

    Here are the numbers from taginfo:
    246k paths tagged with designation=public_footpath
    58k of these paths are also tagged with foot=yes
    59k of these paths have no foot tags
    138k of these paths are also tagged with foot=designated

    So 45% of designated paths are not tagged with foot=designated, but only half of these are tag transformed to foot=ft_designated, leaving 58k of designated paths as foot=ft_yes.

    The suggestion to use of access tag is not useful, only 1480 (0.5%) of these designated paths have access tags set, and in all these cases they are set to access=yes.

    I notice that the default values for tagging in id editor for path and footway are different:
    Highway=path defaults to foot=yes
    Highway=footway defaults to foot=designated

    So this problem will continue to persist and will be randomly set based on taggers usage of path over footway. For designated paths (designation=public_footpath) this is split currently 88% footway and 12% path.

    Given that the designation tags are mostly only used in england/Wales, and they represent legally accessible footpaths which are also required to display signage, all these footpaths should IMO be considered as foot=ft_designated (which implicitly also means foot=ft_yes too, right?)

    The alternative of editing all 58k footpaths to manually change/correct foot=yes to foot=designated seems impractical.

    #47584
    Tobias
    Keymaster

    In the earlier days of OAM we had some similar assumptions, but we learned (sometimes the hard way) that assuming something is similar can generate more problems.
    So again – how do you know that the designation=* tag is the correct one, and not the foot=*, so that overwriting the foot=* is correct? You simply can’t.
    And having foot=yes instead of foot=designation is no problem for the user – a hiker is allowed to use both, so this is an non-issue from a user perspective.

    The suggestion to use of access tag is not useful, only 1480 (0.5%) of these designated paths have access tags set, and in all these cases they are set to access=yes.

    I haven’t suggested using access=*, I wrote about access tags as a tag group – to which foot=* belongs to:
    https://wiki.openstreetmap.org/wiki/Key:access
    And we also can’t add designation=*, as it would bring us closer to the 15 tag limit of mapsforge.

    Developer of Elevate mapstyle

    #47646
    karlchick
    Participant

    Ah, OK I understand the point now. And given that only about 80% of the designation= tags are used in the UK, you are correct, there will be some cases where we can not make this assumption.

    Looking further into usage of designation tag in England and Wales, there is another tag that is used only in the England/Wlaes in combination with the designation tag, this is prow_ref, where PROW stands for Public Right Of Way. There is an osm wiki on this here:

    https://wiki.openstreetmap.org/wiki/Key:prow_ref

    This tag is to only be used in England/Wales and is used to define in OSM the legally public rights of way for footpaths, bridleways, byways and restricted byways.

    note that all paths tagged with prow_ref are legally publicly accessible paths in the England/Wales and local parishes/councils are legally required to ensure that they are signposted where the path meets/joins a public road.

    Hence these paths are explicitly designated as accessible for pedestrians, which OSM also indicates it is valid to use foot=designated, instead of foot=yes. In England/Wales there are many paths tagged only using foot=yes and many of these are not legal PROW. In fact foot=yes is the default in the osm id editor for highway=path, so not a good indicator for legally accessible PROW (at least in England/Wales).

    It would seem perfectly correct to assume if a route is marked as:
    – highway = path | footway
    – prow_ref = *
    – designation = *
    then we can corrctly override foot = ~|yes to be:
    – foot = designation

    I realise that this would only be applicable for England/Wales… but I think it would be greatly appreciated by all the people that walk in the UK if we can finally ensure that PROW are acknowledged, even it is indirectly via foot=designated. I guess it would not be favoured to add a new tag for prow_ref…. also given the size of the text for these fields… although a custom prow=prow_yes field would be ideal too… but I know, 15 tag limited etc… hence foot=designated would be a good compromise and have no impact on existing themes…

    ever hopeful, Karl.

    #47654
    Tobias
    Keymaster

    It doesn’t make a difference if we use prow_ref=* or designation=* to overwrite an existing foot=*.
    No tag is more legitimate than another, despite it sounds more official. All data to OSM is added by users, sometimes in official assignment (like tourist offices), but that doesn’t make the mapping more correct, often quite to the contrary. Ways are often tagged by various users, retagged, split up, joined etc., which can result in leftover or redundant tags. This is also a common source of inconsistent tagging.
    Trying to solve this automatically can result in different problems, see above. OSM data isn’t perfect, we have to live with it, and keep this in mind.

    Yes, we added the designation=* tags to the relevant access tags, if those access tags don’t have any value. But the access tags are the primary tags for the legal status, and these are the tags that are way more used, so replacing those is not they way to go. If something is contradictory, those things should be solved in the data by mappers with local knowledge; also in mapping automatic changes (mechanical edits) are not recommended:
    https://wiki.openstreetmap.org/wiki/What%27s_the_problem_with_mechanical_edits%3F

    As I wrote above, adding an additional tag to highway=* is a no go because of the 15 tag limit.

    Developer of Elevate mapstyle

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