OpenStreetMap
Sidewalk mapped separately
Posted by deptho on 12 July 2023 in English. Last updated on 13 July 2023.Carried out some updates while in a different area. The sidewalks/ pavements were mapped separately from the associated road. This made it a pain to improve road alignment and routing results were not ideal. Using the sidewalk tag on the road object and joining a physically separate path object to it seems easier/clearer?
Discussion
Comment from Glassman on 12 July 2023 at 23:25
I started out mapping sidewalks as a road attribute but discovered that it doesn’t work for sidewalk routing. Mapping sidewalks as separate footways solves that problem. While OSM may have started mapping roads, there is a portion of the population that uses footways to get around. This is especially important for people with limited mobility. Knowing where kerb cuts exits is very important to people with limited mobility. Mapping footways as separate footways solves that problem.
Plus - trying to route yourself on Google. If there are stair involved, Google fails miserably. Probably because there is no money to be made. OSM solves that problem.
Mapping footways as separate ways is more difficult, but it does pay off in the end.
Check out https://wiki.openstreetmap.org/wiki/Sidewalks
Happy Mapping,
Comment from deptho on 13 July 2023 at 04:56
Thanks. I was working on the basics you should be able cross a road anywhere but appreciate separate paths with defined cross points (associated with tactile paving/lowered kerbs/traffic control) would be very helpful.
Comment from SK53 on 13 July 2023 at 14:26
@Glassman : I think this really depends where you are. In general separately mapped sidewalks in the UK usually produce worse results (as I learnt long ago when a national public transport app gave an estimate 4x actual time required to walk from my brother’s house to the bus stop).
Separate sidewalks are much more prone to lack of connectivity issues: and for the UK in practice require adding crossings at every road intersection (which in many cases do not exist in any visible form) to provide sensible routing. It is very hard to update whole suburbs in this way, and given that sidewalk-as-tag mapping produces sensible pedestrian routing is often a counterproductive use of mapper effort.
Both SomeoneElse and I examined various practical issues regarding this tagging when we both had elderly parents with mobility issues. His Dad used a mobility scooter, and my Mum used a wheelchair. In both cases, and I see it now with my own Dad who uses two sticks, the best places to cross were often not at marked crossings with dropped kerbs, but places where driveways to houses were more-or-less opposite. These locations often offer better visibility than at crossing points at road junctions where older people take longer to perceive traffic (particularly any that is turning). There are also many more of them, allowing the choice of avoiding ones where visibility is obscured by parked cars.
Comment from deptho on 14 July 2023 at 12:05
Thanks both. I’ll stick with the sidewalk tag and be careful not to break other peoples separately mapped pavements.
Comment from barefootstache on 23 July 2023 at 02:29
Sidewalk mapping is a skilled practice and should be critically thought through before separating it from the binding road. Lots of times sidewalk surfaces alter frequently not to include the alterations by crossings. This would then create unnecessary nodes along the adjacent road.
Additionally if there is a green space between the road and sidewalk this information is removed. If it is just grass one could question, if the separation is needed, but as soon as trees or shrubbery are in play that puts a whole different twist onto it. There are plenty other amenities and POIs that exist between a sidewalk and road.
The navigation problem for pedestrians is a tricky one. Is one mapping for the routing agent or is one mapping the correctness of the world !? There is no easy answer for this and every mapper should choose which one makes more sense in the situation. Though sidewalks usually are frequently connected to driveways, so the routing issue should be quite minute, as long as driveways are also mapped.
My main way of transport is by foot and for me it is much easier to visually see if there is a separate sidewalk on the map then trying to get the data from the adjacent road.
Comment from SomeoneElse on 23 July 2023 at 10:21
Just to expand on what SK53 said above:
One of the key discoveries for me was that to understand the issues you absolutely need to survey in-person, arguably in or with one of the vehicles that you’re surveying access for. Many official “crossings” (while useful for cyclists) weren’t great for mobility scooters because if turning circle or camber issues - dropped kerbs where private driveways exited were much more useful. Another was that gates designed to deter cyclists but permit wheelchairs didn’t work for all mobility scooters (turning circle again).
Another, related to turning circle issues was that knowing width was important. More more on this, see the tagging list thread here and other related threads at around that time with the same posters in them.
Finally my general takeaway was that the overall quality and detail of mapping required to be useful for wheelchair and mobility scooter routing was significantly higher than what most people just “mapping sidewalks separately” (or not) are doing. A logical way to capture this sort of information would be expanding on what e.g. StreetComplete do now - but it’d need a level of expertise about the problem that apps like that are designed not to need.
Comment from CRCulver on 23 July 2023 at 17:23
In some countries now (Poland is a good example), so many of the sidewalks are actually combined or segregated footways/cycleways. This means they have to be tagged separately using the relevant preset, so that bicycle routing is improved. Also, a sidewalk will possibly have different surface= and smoothness= values from the road that runs alongside it.
Comment from Hungerburg on 23 July 2023 at 20:19
The biggest promise in mapping sidewalks as separate ways is, that businesses can make a so-called pedestrian router that is just a copy of their car router, but operates on a different grid. The ones to gain the most are people in mobility scooters, a car-like vehicle. The visually impaired here do not use any navigation aids, it so, they use google maps. They know about blind-square. In my opinion, the blind should be the ones to profit the most from a true pedestrian router. That though requires more than just a separately mapped grid - one for pedestrian, one for vehicles. Unfortunately, there is not much money to be made from them.
Comment from rodolfovargas on 25 July 2023 at 13:33
Si puede ser “más facil”, pero para nada más claro. El objetivo de mapear ACERAS de manera independiente a calles, depende del enfoque que tienes al dibujar cartografía. En mi caso, el enfoque que yo le doy al dibujar cartografía en OSM es de transitabilidad PEATONAL. Pocos se concentra en mapear rutas peatonales, para diferentes usuarios (tercera edad, niños, capacidades diferentes, bicicletas, …)