I’m very confused with tracktype and other similar tags, and I am unable to find a clear explanation.
The OSM wiki states that “tracktype is a measure of how well maintained a track or other road is”. However, the comments in the values table seem to suggest that tracktype is a measure of firmness (ranging form hard/paved/sealed to soft/uncompacted surfaces) which is confirmed by the smoothness page that states that tracktype “refers to surface firmness, regardless of shape”.
So, let’s assume that well maintained tracks are generally firmer than unmaintained ones to connect both concepts. In this case, there are some marginal but not uncommon real-world cases that I find difficult to graduate:
Bedrock tracks. They are intrinsically unmaintained but generally very compact. They can be sometimes very smooth.
Hard-soil tracks with loose less-than-fist-size stones that do not compromise vehicle traction.
Maintained deep fine gravel tracks (loose by nature) which are fine for cars but problematic for bicycles.
You’re touching upon some of the inherent weaknesses of “quality” tags like tracktype and smoothness. There is an endless variety of road and path surfaces that vary in quality and also depend on the vehicle you use.
The confusion about tracktype may be caused by its history: it started out as a measure of passability of tracks (now covered by smoothness), but evolved towards a measure of surface composition (mix of hard and soft materials) and then as a measure of surface firmness. I would continue to use it in its latest meaning, i.e. surface firmness.
Definitely tracktype=grade1 (even though it’s not paved)
tracktype=grade2, because you state it’s “hard-soil”
That’s a tricky one: the last word on how this should be tagged hasn’t been written yet. I’m a car-centric person so would tag it surface=fine_gravel + smoothness=intermediate (probably) + tracktype=grade3 (even though it’s not a mix of hard and soft materials, fine gravel by itself is medium-soft for broad tires). But a bicycle-centric mapper may tag it as tracktype=grade5 because it’s as soft as mud for his bike. That it’s hard to ride on is a property of the surface itself, so maybe we should invent a new surface value for it: surface=loose_gravel (and surface=loose_sand, with implied meaning “hard to ride, but no problem to drive”).
So your recommendation is to use tracktype as “perceived” firmness, ignoring maintenance status and track composition mixture (hard/soft) as suggested by the wiki, isn’t it? It seems logical to me.
In my home area most of the tracks are naturally compacted (a hard mixture of sand and rocks) but partly covered by loose fist-size rocks. By car, these tracks feel harsh and firm. Thin bicycle wheels don’t sink. I usually tagged them tracktype=3, mainly because fist-size rocks didn’t seem to fit the “gravel road” definition for 2, and there were hard enough to rule out 4 or 5. Then I added the smoothness and mtb:scale/:uphill tags to let car and bicycle users figure out how passable the track was. Should I have tagged them tracktype=2?
But a bicycle-centric mapper may tag it as tracktype=grade5because it’s as soft as mud for his bike.
Hence, are we discussing floatability when we talk about softness?
The idea that tracktype is about firmness really only makes sense in places where the ground is naturally soft. The tag has always been a rough classification based on a few different factors but essentially boiling down to how well developed the track is. On the top end a grade1 is a well developed road and on the low end a grade5 is a faint imprint on the landscape that barely qualifies as a road. It does not make sense for a faint track to be tagged grade1 just because it traverses naturally firm ground.
My understanding of tracktype is very much the same as explained by @ezekielf. The different values reflect the stage of development work invested and (less important) maintenance.
Grade 5 nearly undeveloped: the only work done was to remove vegetation, flatten some bad bumps and holes and remove big loose stones.
Grade 4 development includes some levelling of the complete track, removing more-than-fist-size-stones, adding some gravel here and there to stabilize soft sections, but not much more. Heavy machinery may be used but to a limited scope only.
Grade 3 development includes full levelling and a certain degree of compaction of the track to create a more or less consistent surface. Heavy machinery has to be used normally.
Grade 2 development includes a solid substructure (mixed gravel of different granulation) and a fully compacted surface. Construction not possible without intensive use of heavy machinery.
Grade 1 development finally adds a pavement as top layer.
More details are added by surface=* and smoothness=* as you are aware already.
hard soil tracks tracktype=grade5/grade4/grade3 + surface=ground + smoothness=*
deep fine gravel tracks tracktype=grade3/grade2 + surface=fine_gravel + smoothness=*
The last smoothness depending on how “deep” the fine gravel layer is. According to my own experience deep fine gravel tracks don’t remain “deep” for long time, specially when motor vehicles are driving there, as fine gravel tends to be brushed aside by fast moving vehicles quickly.
I strongly disagree with @ezekielf and @Map_HeRo : it is in disagreement with the wiki and would be a complete redefinition of tracktype.
I think that how “good” (well-developed, maintained,…) a road is should be expressed by smoothness. A well developed/maintained, i.e. newly built road is likely to be with a high degree of smoothness (paved with asphalt or concrete is likely to be smoothness=excellent, surface=paving_stones is probably less smooth when new, and surface=sett is likely to be less smooth than that. Due to use, a road deteriorates, which can be expressed by tagging it with a worse smoothness value, until maintenance comes along and the smoothness is improved.
For unpaved roads (tracks), it all depends on the amount of effort that has been put into building the road. Has additional material such as gravel been added, has it been compacted or just bulldozed, or was there no building at all (a track formed by driving on a natural surface)? Again smoothness is a measure of the quality of a surface, and additionally it can be tagged with tracktype to express the firmness of the surface (which is related to the mix of hard (stones) and soft (sand, clay) material in the surface, with more stones leading to a firmer surface). I think tracktype has limited practical value (I usually don’t bother to tag it), but could be used as an estimation of how fast the surface quality changes upon use, wet weather, etc. as well as the risk of getting stuck on a track because your vehicle sinks into the surface. tracktype=grade1 is very solid, so very unlikely to change due to use or wet weather, while tracktype=grade5is very soft, so after rainy weather it will likely be very muddy, and a heavy vehicle is likely to get stuck.
A look back at history: Proposal:Grade1-5 - OpenStreetMap Wiki before it went to vote (which never happened.) Will openstreetmap ever get as simple as that? The pictures quite telling, at least for what I observe in the area of my local knowledge.
If tracktype only maps firmness, then perhaps it is mostly meaningless in your area. Can you share a photo or two?
The hedges prominent in description, less so in the photos, actually only grade 3 and 4 segregated by hedges. Perhaps a very locally grounded concept, still applies quite well outside of Britain too, e.g. here where I hail from, likely not all over the world, though.
The photos still feature in the main documentation. While they are a bit about firmness, I still wonder why tracktypeshould map firmness only, shouldn’t the key then be renamed info surface_firmness? The pictures definitely also show the different efforts that went into construction; an objective measure, not?
I was under the impression that smoothness is an indication of the minimum robustness of wheels needed to use the way, e.g. city racing bikes with thin tires cannot accept anything lower than the highest value, normal bikes can use the 2nd highest value, cars can use the top 5 values, etc.
Also, smoothness= should be tagged as the worst part of the way, while tracktype might be more of an overall average?
Yes, that’s how road surface quality is expressed. An excellent road can be used by any wheeled vehicle, while a road that can’t be used by most vehicles is very bad.
In your comment you put most of the weight onto the firmness of the surface for the choice of the tracktype without considering that this firmness represents the grade of development and also maintenance. In road construction “soft” does not mean that vehicles generally sink into the ground but that the upper layer has not been reinforced or compacted. To achieve a “firm” surface a certain degree of development work is necessary and to preserve the result of the work a certain degree of maintenance is indispensable.
From that point of view the grades of development I described in #7 match the descriptions and sample pics in the wiki quite well imo.
The only situation which has not been adressed in the wiki are tracks made up of natural rocky or scree passages. These are physical “hard” and there is no risk of sinking into the surface but in the sense of road construction this is a soft surface as long as not improved by human development. Such tracks in most cases are not consistently firm, there can be cracks and gaps and loose rocks and the quality may change quickly when there is a lot of traffic.
The same applies to lot of undeveloped roads in tropical countries. Laterite and similar surfaces are very common there which are hard as rock and a track bulldozed on such surface appears very firm so one could rank such road as grade 1 or 2 when new. But these surfaces are not consistent and will deteriorate very quickly under traffic so in fact they are not better than grade 4 to 5.
That is a meaning of the word “soft” that I was not aware of, and I’m wondering how many mappers share my ignorance… If so, the wiki needs to be clarified about this. “Even mixture of hard and soft materials.” for Grade3 is then misleading, for instance, because it seems to refer to the physical softness of the materials in the surface, not about the medium amount of work done to create and maintain the road.
I’m also wondering what the practical use of such information is. What additional information useful to map users is contained in your interpretation of tracktype that is not yet covered by smoothness?
You generally seem to despise the key tracktype. You wrote, you rather not use it. I also see problems arising with numbered grades - e.g. at crossroads grades may appear different than when no immediate track to compare. I guess that why tracktype considered subjective.
The remedy for that, to turn it into a measure of surface firmness strikes me as even more wilful though. Here in Winter no track is soft, they all hard. Where does this remedy come from, it is not in the original proposal, the original proposal is all about the effort spent into construction (and hedges btw. supporting that interpretation.)
I came here looking for advice and I couldn’t anticipate that my seemingly simple question would spark such a passionate debate
To be honest, I struggle to see a clear difference in track development alone between grades 3, 4 and 5 based on the wiki pics.
Grade 3 track seems more compact due do likely harder underlying materials and higher traffic compared to grade 4 track. However it doesn’t seem that anyone has put significantly more effort in neither of the two. In fact, I notice potholes in grade 3 track which doesn’t seem to be present in grade 4 track.
On the other hand, the only difference I see between the grade 3 and grade 5 tracks is their usage: the grade 5 track resembles the grade 3 track after several months of disuse. Unfortunately, I believe that this has nothing to do with maintenance, because it’s often the regular traffic that keeps tracks free of vegetation.
I fear that hardness and development/maintenance alone do not answer my question.
I feel the same confusion regarding the track_type as you do. When I map based on the aerial imagery in Central Europe I created simple private “system” to evaluate the track type:
the way is accessible to 4-wheeled motor vehicles,
the main reason why it exists is probably to serve the agricultural needs of its surrounding,
every such visible way covered with grass only is grade5,
a way covered with dirt with two paralel wheel tracks visible on aerial imagery is grade3,
everything else which seems to be paved (e. g. by asphalt, concrete) is grade1.
If there are doubts I omit track_type at all.
I am not sure if this is the acceptable approach, I am looking forward to read any comments from others.
This is not a good measure. two visible parallel wheel tracks can be everything between a concrete:lane or dirty grade1 and a grade5 track on bare soft earth.
I would advise against guessing tracktypes larger than grade2 from aerial images.
, I’m wondering why. Am I reading the wiki wrong, is the wiki wrong, or…?
