It is rendered, because footway=link has to be combined with highway=footway. It just describes what subtype of footway it is, similar to footway=sidewalk or footway=crossing.
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Link footway was added to represent the understood paths a person would follow between two otherwise disconnected pedestrian networks. It can be used to explicitly connect pedestrian and street networks in a consistent way that a router could use. Parking lot transversing and be ability to move from a mid-segment kerb cut to a car stopped in the normal flow of traffic. Iit is also used to connect a lenght of sidewalk to the road when there are no surrounding footways on the other side of the street.
I’m mostly interested in cycling infrastructure. In England, most cycling infrastructure that isn’t shared use paths in parks consists of shared use footways (pavements/sidewalks) parallel to roads. Therefore I map many paths alongside roads which are also tagged as footway=sidewalk.
For the foot-only sections, these days I tend to only map it if the way is complex, or if there is a something like a staggered crossing, where I would need to stop at least twice when crossing a road. As others have mentioned, I think it’s important that, if mapped, footways are joined to roads in a realistic way. These days, I try to tag the kerbs separately to the crossings (i.e. the kerbs are situated on the link between the road and the footway, and the crossing is a node where the footway joins the road way).
For shared use paths, I always map these separately as highway=cycleway or sometimes as highway=path (especially if they are shared use with cyclists, horses, and pedestrians, but not a Public Bridleway).
Quoting from a posting I made to the talk-gb mailing list:-
This is one reason why I disagree with people who delete cycleways and replace with a generic cycleway=track on the road. The data on dropped kerbs, inaccessible barriers, and dismount sections are lost. The late Heavy Metal Handcyclist https://twitter.com/CrippledCyclist used to post on Twitter on how they would get councils to remove such barriers (their cycle was their mobility aid). From my point of view, having my pannier bags full of shopping or stuff for my holiday means I can’t just dismount and push my bike over a raised kerb, and getting round narrow gaps in barriers is impossible. Similarly, people tagging non-cyclable ways as bicycle=yes makes journey planning problematic.
- Many shared use paths have barriers - as mentioned above, these can affect whether or not I can get through with full pannier bags. I can imagine that someone with a cargo bike or a cycle as a mobility aid would struggle with most of the barriers installed on shared use paths.
- Sometimes the kerbs are not dropped where the path meets a road
- Sometimes they have sections marked with “Cyclists Dismount” signs (someone using a cycle as a mobility aid may be unable to dismount).
- A shared use path alongside a road won’t be affected by the traffic lights on the roads (although a fully segregated cycle track might have duplicate traffic lights at junctions or for pedestrian crossings).
- Similarly, a shared use path will have different traffic calming to the road.
- A shared use path will lose priority at side roads, and all those crossings reduce safety compared with cycling straight along a road where you have priority over side roads.
- The shared use path could be sufficiently far from the centre line of the associated road that a sat nav would be continually bleating that you are off course.
- Getting from a shared use path to a road on the opposite side of the road can be a challenge if there’s not a crossing - I really need a dropped kerb in order to access the road from the shared use path.
All this information is lost with “cycleway=track” on the road.
Jon
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The issue here is not only legality, but also accessiblity. Many people moving with assistance of wheelchairs, or other walking assist devices cannot just decide to cut across the verge and curb and go where they want, even if it is legal.
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True.
However, the kerb tag allows to specify where kerbs are located and also contain information about their height. This tag can be used directly on the road, i.e. it doesn’t require sidewalks to be mapped separately. If the kerb differs between both sides then kerb:left=* and kerb:right=* can be used.
yes, you can add kerb information to the nearby highway, but it can lead to a lot of fragmentation, ultimately for “implicit” features that are not about the highway itself but about the sidewalks that run along and how they are separated. It seems less intuitive and transparent, and still is not able to represent geometric detail and the position of the sidewalk with respect to things between the sidewalk and the carriageway
I find that it’s easier to map sidewalks as separate ways because all the OSM tooling that I’ve run across makes it easy to edit ways, but much harder to edit the same date represented as attributes.
Standardizing on this would make it easier to onboard new mappers.
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Maybe creating a new type of relation, that should contain sidewalks and higways??
That looks cool but without examples I can’t use it
Why is there a need to connect the two ways via a relation? Most routers can detect whether a footway is related to a named road it might run parallel to. Even then, pedestrian directions are relative to the road(s) it crosses not borders. Making it vitality important that the crossings are mapped with enough detail that the router can determine if and where a pedestrian is even able to safely move between two pathes. As a result of having genric kerb information attached to the street will lead to inaccurate routing. It could quickly turn life threatening when it is supplied to someone in a wheelchair or tjat is blind. Not being able to quickly navigate a corner could lead to falling in to the path of vehicles.
Why is there a need to connect the two ways via a relation? Most routers can detect whether a footway is related to a named road it might run parallel to.
one can only guess if there is no explicit relation, just because the ways run parallel does not mean you can change from one to the other, for example one could be several meters higher and separated by a retaining wall from the other.
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It’s also possible to map walls, retaining walls, fences and other barriers to indicate, that ways can’t be changed. Also tags like cutting, embankment, incline,… can be used. That’s more intuitive and represents what’s “on the ground”.
Of course you can add all these details to OSM. But they won’t make it unambiguous in all cases.
Apart from that, routers typically use only a subset of data in order to reduce storage constraints and computation effort. Information like walls, fences, cuttings, embankments etc. are typically ignored and thus not even in their database. Having to consider all these information seems a little odd, especially given that routing in OSM is already quite complex.
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Do you have an example of a router automatically associating sidewalks with roadways? It’s one thing for the router to prefer the sidewalk over the roadway, but that’s just a matter of boosting sidewalks or penalizing roadways. It’s a bigger feat to include the sidewalk geometry in the route but reliably refer to it by the road’s name in guidance instructions and avoid overly detailed instructions around intersections.
I’m pretty sure one could get decent results by map matching the sidewalk coordinates to the road network, in the same manner that one might clean up a messy GPS trace (with all the same caveats). But I don’t know if it would be practical to perform this map matching performantly as part of a standard pedestrian route calculation.
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It’s also possible to map walls, retaining walls, fences and other barriers to indicate, that ways can’t be changed.
yes, you can map these, but assuming if they are not mapped then they don’t exist would not be prudent
Cheers Martin
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Yes, you’re right - an important point I didn’t consider. This would affect a reliable routing.
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Separated sidewalks have to be mapped or effectively don’t exist. Specifically because because they form thier own distinct set of surfaces meant for pedestrian and sometimes other traffic. It more important to know to travse a crossing itself along the names of streets being crosed. Without sometype of matching kerb cut, the parellel street becomes a landmark. This becomes painful obvious when crossing the road anywhere other than signaled could be deadly due to high speed traffic.
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The preferred way to indicate that is a tag “sidewalk=separate” on the carriageway. Note that for a pedestrian router the most important aspect is to not route along the carriageway.
The problem of crossing outside crossings is simple the opposite of “safe router”. A pedestrian router will have to deal with a lot of somewhat impaired people although they consider themselves to fall into the ordinary pedestrian routing profile - rightly so. Thus, it is simply not safe to assume that a pedestrian can cross outside a crossing.