How to map Key:smoothness

I went for bad because it’s visually similar to pictures of bad on the Wiki. Of course in real life I don’t tag smoothness based on eyeballing a photo.

I’m afraid it’s not as simple as that. The picture you have put up for discussion is literally the example picture of bad that StreetComplete shows to its users when deciding how to tag smoothness when the surface is paving_stones. So why don’t you open a ticket in the StreetComplete issue tracker and ask them to use one of the other pictures? Otherwise the Wiki and StreetComplete would directly contradict each other.

In fairness, the StreetComplete quest is disabled by default and the user is warned when enabling it that it’s often hard to make the right choice.

For the gallery, we could try and have pictures that we mostly agree on, instead of edge cases? So I suggest removing this picture instead of moving it to intermediate.


For the gallery, we could try and have pictures that we mostly agree on, instead of edge cases? So I suggest removing this picture instead of moving it to intermediate.

looking at the street complete options I think they are well chosen and make sense in the context of a paving stones surface.

Maybe we should take it as a model and have example pictures for every smoothness value ordered by surface?


:heart: :heart: :heart: I think StreetComplete (and before, this gallery) went the wrong way by stressing visual comparison of the situation on the ground with example photos. I think the way to tag smoothness is to try to imagine using the way with the vehicles mentioned in the wiki. See also here. The explanatory text and the example photos in the wiki were added by me only 3 years ago (with discussion only on the talk page of the wiki, as I hadn’t found this forum yet) to make tagging a bit less subjective and more verifiable. I proposed to move away from visual evaluation in StreetComplete here but it was rejected.

I know, it’s the reason why I picked this photo as the first to discuss because I wanted to be sure it’s not only me who thinks it’s not suitable for illustrating smoothness=bad: at first sight, the surface quality looks as good as the “mostly even” image, and only when looking closely you notice the wide gaps between the bricks. I think it appears about as rough as the “A little bumpy” picture.

I will, as soon as we have consensus here on what should be on the Wiki.

I have in mind that we discuss most of the pictures in the Gallery here, beginning with what seem to be the most controversial ones, and then move a picture if deemed necessary and add a caption with a summary of our discussion and the result of the vote. I think edge cases are especially interesting to show what different mappers are considering when tagging smoothness.

To me the observation above is the primary reason why I tend to agree with @Richard that smoothness (and tracktype) adds little value on top of surface tag for routing profiles (I have also developed several for different cycling modes + foot). Different types of “vehicles” simply suffer in different ways from road / track / path imperfections. Then take into account the difficulty in objective grading and ratio of tagged vs. non-tagged and one will find it quite hard to design a routing profile that would effectively utilise the this tag.

I do agree though that there are specific cases where it would work quite well: e.g. routing only on roads that have a suitable surface tag and a smoothness tag with a “high” value (excellent / good) you would get a route that would be quite smooth (with high probability) for e.g. racing cycle. However, would you rather have that or a shorter route with equal quality (but missing smoothness tags) or nearly as smooth but otherwise maybe better (with e.g. intermediate values for smoothness)? That is the problem that a general purpose routing profile needs to solve. And once you have a service / application out there you start to get feedback from the users about the “routing solutions” which truly opens one’s eyes to the challenge.

I’m currently trying to solve a subset of the topic of this discussion thread: develop appropriate tagging (for Finland) for gravel bikes. As a foundation we have a very active mtb-mapping community (with +24000km of paths mapped & tagged with mtb:scale, I think only Italy is ahead of us in Europe) and we have extensively discussed the challenges of mtb:scale tag - however are reasonable happy with the outcome. We are still debating the approach to tag for gravel biking, that would appropriately describe the surface impact to speed and comfort - and this is just one specific vehicle we are trying to tackle…

From what you write, I understand that the weakness of smoothness is more the low share of highways tagged than an inherent weakness of the tag itself. Surely smoothness tells more about the quality of a road or path surface than surface? A road tagged with surface=asphalt could be newly paved or full of potholes: the surface value doesn’t contain any information about that. Statistic will probably show that surface=asphalt roads are generally better than surface=ground roads, but there are surface=ground roads that are better than surface=asphalt roads, and you can’t tell from the surface value alone if that might be the case. But a road tagged with smoothness=intermediate is quite likely to be better (more comfortable, safer for your vehicle and faster) than a smoothness=bad road, even though there are mappers who would tag the intermediate road with bad, and others who would tag the bad road intermediate if they are edge cases. However, most mappers will be able to agree on a ranking of road qualities from excellent to very horrible, though they might disagree on the borders between the categories (this is what is verifiable about smoothness).
I live and map mostly in Bulgaria, where road quality shows a larger variation than in North/Western Europe and is of crucial importance in choosing a route. This initiative by @ivanatora and @REAKTOR invites the general public to submit road quality data to them, which they then add as smoothness tags to the reported roads. It has been quite successful, and often leads to roads being tagged with smoothness before they are being tagged with surface. I take this as an indication that map users here (i.e. our end customers) are more interested in the quality of the road than in what its surface is.
"Google and Apple maps do not differentiate between a good road and a bad road - but that’s so important". It’s one of the areas in which OSM can really make a difference and offer some advantage over Google Maps


I meant having a picture for every smoothness value as applying to a specific surface combination. Thank you for pointing out in private that there is already such a table: Key:smoothness/Gallery - OpenStreetMap Wiki

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The weakness is a combination of tagging ratio, mapper consistency and specification of how tag values should be used. I did not mean to say that there is “no value”, just that there is not a whole lot of extra value (to the type of needs I have been exposed to). With your example you raised a very valid point on how local circumstances and main use case impact tagging usefulness. I can understand that 4-wheel vehicles & bad quality roads (even for asphalt) is a type of need that smoothness tag can help with if you manage to mobilise the mapping community.

Local circumstances around here are different: my main interest is bicycles of different sorts, paved roads around here are not perfect, but good enough that even for a narrow tired racing bikes do not need to care unless one is very keen to maximise comfort. However on unpaved roads conditions are very dynamic: due to winter the roads can be in extremely bad shape in spring with deep potholes, terrible for cars, a bit uncomfortable but not a big problem for bikes. And then they do the maintenance for unpaved roads to fix potholes, which fixes it for cars instantly, but is terrible for bikes until the fresh gravel-sand mixture settles, then the road is typically pretty good for everyone. In autumn some unpaved roads get so wet that riding a bike is feeling like riding in a swamp.

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I think the photos do a good job to set the expectations and help to use similar judgement for similar situations. Rather than just removing the pictures we could replace the 1-2 examples per value as they are currently shown here:
with the more exhaustive table of example photos by surface type here: Key:smoothness/Gallery - OpenStreetMap Wiki
because I guess many mappers will rather just look on the provided pictures and not necessarily follow the links from the fine print. If you are interested in information about a tag, and there is a table of values and pictures, the assumption is that this is the current state of the art.

If we find that good smoothness value can be determined for different transport modes, but the different transport modes don’t agree on a single smoothness value, then tag that as smoothness:* = *

Alternatively, if a smoothness value just doesn’t make sense on a particular road due to seasonable variations, just leave it out.

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Or, assuming it varies predictably with season, wet_season:smoothness=* etc.

Sure, if that’s what you want to do.

That’s fine with me too, it does look like it was recently graded, although one should keep in mind what that road is going to be like in 6 months or a year. Unpaved roads in my part of the world get washboarded in a short time and get very occasional or rare maintenance. Intermediate and bad are both passenger car roads which is the main criteria for an unpaved road. The distinction is subtle, and ‘intermediate’ unpaved roads don’t stay that way for long.

I’ve been there & I disagree. Perhaps it’s not the best example, but iI consider it a high clearance road & is “passable with an average SUV”. I reserve horrible for roads a little worse.

I’m with you on almost everything & I’m mostly with you on this. I definitely don’t think we should be micromapping roads, but if something is tagged very_bad or horrible (high clearance or 4wd) and a user see the beginning of the road as pretty good they might conclude the tagging is wrong and venture forth. If there’s a half mile of bad road in middle of the good road, and it’s rendered appropriately one can make a more informed decision. I do this rarely, but here’s an example of a short 4wd (horrible) section in an otherwise high clearance (very_bad) road: Poncha Creek Road

Well; if anything, I’d say such results would indicate that such picture should be removed, as if people tag according only to that picture, the inferred meaning would be wrong in 40% of the cases, so it is obviously not a very good picture if this sample of users is any representation of reality (that is, the situation/tagging it associates has ambiguous meanings).

Another issue is that changing what the EXACTLY SAME PICTURE means today compared to what it meant yesterday is horrible UX, guaranteed to produce much more misery than it could ever hope to solve.

In addition to creating obvious huge amount of confusion, changing what the people though some tag meant would invalidate many of pre-existing “bad” and all future “intermediate” uses of that tag of people, making those two values in combination with surface=paving_stones unusable for all future (unless it was accompanied with mechanical edits removing all such values from the map first and preferably contacting the editors who used that in the past about the new meaning)

So, IMHO - either keep the status quo (thus at least not disturbing how it is is used and thus making all existing “bad” and all future “intermediate” problematic), or (better, but much more work) completely remove that picture by replacing it with something else (preferably something that creates less confusion, e.g. whose size is more likely to be correctly interpreted how big and deep the gaps are in reality, so there is [hopefully significantly] more than 60% of the users which agrees what it actually represents - probably best procedure would be taking several pictures and putting them to vote to find best candidate, and then checking in another vote whether it produces better results then current 60% match).

Note: One should also take into important consideration that the few dozen people who read this thread and vote are actually insignificant minority compared to number of people who mapped that tag (many of whom has looked at the wiki in the past, or used solution like StreetComplete which had etc.)

So while voting here could be very valuable input to creating new tags/values, for already widely used tags it is much less so - as 99% of the old people will continue using in the ways they’ve already learnt to do in the past. As in practice, only new mapper (who never used that tag before), and few dozen participants in this thread (insignificant) would actually use the new meaning. And all the users who would like to use the values, would have to use at history modification dates and guess is it more likely that users meant old meaning or new meaning?

I suspect that many of the bad voters are cyclists? I agree that this (rather unusual, I think) surface is particularly uncomfortable for cyclists, so maybe if this is the surface of a highway=cycleway, it should be tagged smoothness=bad?

I think that smoothness should be kept as being useful to the most sensitive vehicle that still can still use that surface, as it means the most difference there.

For example:

  • if you drive SUV, you don’t really care very much whether it is good or excellent smoothness of that surface=asphalt. But if you use roller blades, you do care. So the difference between good and excellent should be based primarily on rollerblade users, not SUV users (or other less sensitive vehicles).
  • Same for other values, e.g. intermediate vs bad is mostly interesting to about trekking-class bicycle users - it is not interesting for e.g. rollerblade users (as they can’t really use that surface anyway), and it is not really interesting to e.g. tractor users (as it doesn’t make a difference in their lives at all). While SUV is somewhat affected there, that effect is much less then the effect for trekking bicycle user; so in that specific example trekking bicycle user should be the one for whom the difference between that two smoothness values is primarily focused on (as they are about the most sensitive to that specific difference).

Or should a subtag bicycle:smoothness=* be introduced to handle such exceptions?

To play devil’s advocate; why not invent motorcar:smoothness=* instead and keep smoothness=* bicycle-related? Afterall, there are likely more bicycles in the world than cars :smile:. But, jesting aside, I don’t think that would be good idea in either case, because:

  • firstly, bicycle:* (or motorcar:*) as a prefix to *:smoothness wouldn’t help much. There is as much difference between downhill MTB bicycle and a road racing bicycle, as there is between sports car motor vehicle and an ATV motor vehicle. So It would make as much sense as conflating “sports_car” and “ATV” and “tank” into single category motor_vehicle:smoothness – i.e. not any sense at all, really)
  • secondly, I don’t think trying to chop it down into dozens of subtags (and it would have to go that way if it made sense - e.g. sports_car:smoothness, suv:smoothness, atv:smoothness, mtb:smoothness, city_bike:smoothness, road_bike:smoothness, tank:smoothness…) would do any good, really. It would make complex situation even more complex, harder to tag, harder to user, and overall less likely to be useful, and all that without really solving any issue.

It’s highly dependant on the situation. The main issue for my situations is if that if you don’t have smoothness tagged, you may NOT assume equal quality as you seem to imply above (it might be the same, or better, or - quite often - worse).
I mean, if I knew with certainty it had equal quality, I might as well tag that smoothness, eh? It’s two clicks on the phone in StreetComplete…

So, if I didn’t know the smoothness quality of the the shorter (untagged) route, it depends what I’d do:

  • for myself alone on leisurely ride, regardless of route length, I’ll most often prefer the one without mapped smoothness, even if that smoothness is excellent - because I get to get there and map smoothness in SCEE / StreetComplete for future use (mine and all other OSM users). Also, it means I haven’t been there yet, so for me it is a plus in itself!

  • if I’m leading a group which include at least one road bicycle, I’d definitely choose one with mapped smoothness=excellent and not the one without tagged smoothness, regardless of the length (as to improve group happiness - even if it is risking just one person having to walk just hundred meters in SPD shoes carrying their bike in hands. IME, people seem to like other people trying their best to make the ride enjoyable for everyone, even/especially if they’re in minority)

  • better smoothness does not always equal more preferable. For example, over here if two mostly comparable roads go same places, it is quite likely that the one with worse surface quality will have significantly less cars (and have them moving at slower speeds). So, even when both smoothnesses are known, if you (or your group) prefers quieter roads, and their bicycles are fine with that, they might (perhaps somewhat unexpectedly) intentionally choose intermediate over the excellent one.

  • if I’m leading a group who are all ready for some offroad, depending on the how long we’ve been riding I might try to sneak in that first option in order to get a chance to map some more (e.g. if they’re fresh and full of energy and not sore), or I might put it to vote (“ok, road (a) is longest at 20km, but known good asphalt but also higher car traffic; road (b) is 13km probably asphalt or compacted of unknown but likely lower quality, but car traffic should be much less too; and option (c) is this only 4km long track shortcut through forest but with known bad smoothness ground, which might be still muddy from yesterday rain. What say you?”). And I’ve had groups (even ones of same people with same bicycles!) choose different options at different times, depending on the myriad of factors.

So, I think any router trying to make one-cycling-router-preset-fits-all is doomed to fail (in many use cases). It all depends on very specific circumstances. At least for majority of my rides. YMMV, of course - someone elses rides might be monothonic and deterministic to a fault, or anywhere in between.

Even for same bicycle types (e.g. several routers distinguish MTB vs road bicycle etc.) one user might prefer quite different route from another user with same bicycle type. Sometimes vastly different. smoothness adds a valuable data point allowing people those choices.

e.g. many people get on the bikes not for commuting purposes where e.g. shortest or fastest route might win (even there, some might prefer other factors like safety or variety or being removed as much as possible from car noise/stink much more then they care about mere speed or low mileage), but for many other reasons too.

E.g. many who cycle for recreation do not even want to get from A to B in shortest number of kilometers or in fastest time possible; they might just want to get from A back to A in longest number of kilometers that they can ride which will put them through most amount of nature and least amount of car noise and smells and road stress and repetition, for example. That would be me most of the time, for example :smile:
Or they might want most technically demanding one as they like pushing their limits.
Or they might want one where they get best speeds on their cyclocomputers, or longest or steepest downhills, or whatever.
There are likely more different cycling preferences then there are cyclists, really :laughing:


I think it would be good to preserve the picture and what we have learnt from it, by adding a caption that summarises what we think about it. For this particular one, we could move it to the intermediate column with a caption like “This picture was put up for a vote, where 26 voted for intermediate and 13 for bad. The surface was believed to have worse smoothness for vehicles with narrow tires (bicycles) than for vehicles with broad tires (cars). It was difficult to see how wide the gaps between the paving stones are.” It would be ideal if all pictures in the gallery had such captions…

I agree with you when it is about the meaning of tag values: there should be a very very good reason to change one, with good agreement that it’s really necessary. But this is about a single picture that doesn’t illustrate the tag value as well as others. If there is a significant disagreement between different pictures supposed to illustrate the same tag value, something should be done about it, better sooner than later.

We can only hope that they are a statistically significant representation of all mappers. I don’t think there’s a better way to find the opinion of all mappers.

I agree; I think this is the original idea behind evaluation smoothness. However, in practice it would mean that a mapper should have experience in using at least 7 different vehicles… I think this is not realistic.
I realised from your comment that I don’t have experience in using roller skates or skateboards, which means I can’t really evaluate the difference between excellent and good. Instead, I fall back on visual evaluation of the surface (which I have been arguing against, but now I realise I’m doing it myself).

I think we could make a subtag for single track vs. two-tracked vehicles for those who want to go into such detail, but not beyond that. There is a difference between your city bike and mine, and even between my SUV with inflated tires and with soft tires :smiley: We should not go down the road of more and more detail, because most mappers would not be able to follow and stop mapping it at all. I like it that smoothness is trying to categorise surface quality for several map users at once: this usually works, but not always, and most of the cases where it doesn’t work seem to be because of the different width of the vehicles.

I admire your striving for perfection :grinning: Maybe it would be even better if the router app could also read your thoughts, sense your mood and take into account how well you slept last night, and recommend the perfect route :rofl:

I think the best we can hope for is a router that’s not just car-oriented, and that takes smoothness into account when evaluating 2 alternative routes that both have it tagged (increasingly common in the future, I hope) and tells you that one will be a rougher ride than the other and you should leave your racing bike home and take your MTB

I think this issue is described in the wiki here Key:smoothness - OpenStreetMap Wiki Does it need improvement?

That section of the wiki looks good to me. Overall that wiki page seems pretty good.

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As noted below, I find idea of having the exactly the same picture change the meaning very bad. I’d avoid doing that at any cost.

Sure, if you want to preserve what we learned from it, by all means remove it from Gallery and move it to the talk page and add commentary and/or link to the discussion. For the main Gallery page however, replacement picture(s) should be found both for bad and/or for intermediate if the existing ones are insufficient and would benefit from more examples. But NOT that one which has already been used to mean something else. Surely there exist some other example in the world of that? If not, just remove it without replacement as it is not a good fit.

Sure, I’m not against something being done. Removing the picture seems like a good idea. Reassigning same picture which meant one thing to now mean something different is the only idea I’m opposed to.

Not necessarily, but it would mean not tagging values which you have no idea what they mean.
E.g. if one only have experience with driving a heavy-duty tractor and can only tell the difference between impassable, very_horrible and horrible, and all the rest look the same to them (I’m exaggerating for a reason), than one should probably stick to only mapping those values and leaving mapping the other values to those who do see the difference.
On the other hand, if you’re exclusively roller skater who never used or seen anything else and you can only tell the difference between excellent, good and intermediate and everything below intermediate looks the same to you, than those are the only values you should tag.

Of course, in real life, I guess many people could differentiate a few more values. But the most versatile ones would probably be middle-class-bicycle (like trekking bicycles) riders - they’ll innately know the good-horrible range; and somewhat-guessing excellent & very_horrible as “one below/above known values” would not be too hard for them.
Thus they only might struggle with impassable value sometimes where it is not obvious (e.g. could some ultra-terrain-tractor-monster I’ve never seen possibly go over this mess or no? OTOH, if it is single rope bridge over a river then the answer is obviously going to be “impassable” no matter what vehicle driving experience one has)

Well, I don’t :smile: While it might possibly cover few more very niche situations, it would make mapping and parsing so much more complicated that majority would give up even attempting it. I.e. effort/gain ratio would be waaaay too low, and it would very negatively affect the common situation use.

Better use smoothness:note and/or wikimedia_commons=* to indicate those very specific situations in text and/or picture if you find it is important in some very specific cases.

I’d much rather stick with width=* to indicate those issues.

I know you joke, but well, both default install of OsmAnd, and BRouter already allow me to make such decisions on mobile phone (or even do them automatically for me, yes), so I personally do not require extra AI there. I do want them to provide me with enough details to make a decision which route I want to take; I personally don’t mind having it be semi-manual. Other people probably might want some more AI, though (ones who are uncomfortable with too much options, for example)

So few others web based like, GraphHopper Maps | Route Planner,,,, BRouter web client do offer several different pre-set bicycle profiles, and/or options to tune their routing in even more details.

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The next picture I would like to put up for a vote is the one below. How would you tag the smoothness of this track?

  • intermediate (wheels) city bike, sport cars, wheel chair, Scooter and all below
  • bad (robust_wheels) trekking bike, normal cars, Rickshaw and all below
  • very_bad (high_clearance) Car with high clearance, light-duty off road vehicles
  • horrible (off_road_wheels) heavy-duty off road vehicles and all below
0 voters

Background: see the discussion here. Please read that discussion, add to it if you can, and then vote here. The issue basically is: should “Usable by” in the column header of the wiki table be interpreted as “comfortably usable” or “just passable” (or something in between…)?
FYI the photo has been used in the past to illustrate smoothness=very_bad, but in my opinion shows no obstacles for which high clearance would be an advantage.