to me it looks like mix of some stones (if these would be sole element it would IMHO be surface=gravel) and plenty of soil/sand/dirt/earth
Google street view from the paved part of Tislandsveien. The unpaved road looks to me something that might have been built just with an excavator, with possibly trucks bringing in additional gravel/sand/dirt from somewhere if whatever is locally available isn’t good enough. (I’m hedging this because this is just a street view and I’m not familiar with actual Norwegian road building practices.)
The easiest way to build a low traffic road in our climate/geography is simply digging ditches on both sides and using that material as the road surface. In ideal cirmustances (e.g. depending on the ground material, waterways etc.), a single excavator can create hundreds of meters of road like this per day. And it can be strong enough to carry logging trucks, especially if it only needs to do it in the winter when the ground freezes.
An additional surface layer of gravel or fine gravel can make it a bit stronger/prevent weeds from growing if needed. Or it can be added to cover up erosion after a few years of use. This surface layer will then start wearing out, again exposing whatever was underneath. This is a lifecycle, just as with compacted roads (OSM wiki sense, rollers and water to bind materials).
Still, looking at that image from GSV, it’s clearly a mixture of material sizes (dust, sand, crushed stone, etc) and not what has been described as “fine gravel” in this thread, which is solely uniformly sized crushed (or naturally occurring) stones.
It looks a bit soft to be compacted, since there are clear tyre tracks. I wouldn’t except that from a properly compacted road. So I agree it’s not very well compacted. But it’s the kind of material that could compact with use, or be compacted at some point, whereas the uniformly sized gravel with no finer material discussed here (“singel”) simply won’t.
I would like to link to somewhere to show, but I simply can’t think of anywhere that would have only the crushed stone…
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To me the Tislandsveien gravel road looks very much having a compacted cover. There is even a slight centre line crown in the perpendicular profile, and also nice water drains on the sides, very important to keep state. The crown is made in the base layer of the road and the cover follows that. I do not see prints of tires, but there is a lot of fine gravel on the surface of this track that might get moved by them.
System reminds me, the topic has been solved: Solution was, using compacted for such surfaces is the only choice that cannot be mistaken for deep fine_gravel or ballast sized gravel. I do not hold my breath that the mapping community will tag like that any time soon.
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With that in mind, how would we classify this?
It seems to have a compacted base layer, but a very rough surface layer made up of coarse gravel. It’s arguably more ridable than an OSM compliant gravel road made up entirely of gravel, but surface=compacted doesn’t seem to do it justice either.
From the pictures I see, you are using a pedal cycle. So do I. And that influences how I perceive of things. I’d tag there a surface=gravel and a tracktype=grade3. I am a bit at a loss on what smoothness=* to give, due to smoothness for bicycle and for car not easy to reconcile.
Mind you: From what I know about OSM tagging, surface value compacted is the only tag in the arsenal to mark something like this as usable for logging trucks or timber lorries, or is it grade2 tracktype, I cannot tell. While that may hold here, who do you think uses openstreetmap data?
I am curious if @Map_HeRo would be ready to share an opinion?
There’s a surface layer of gravel. The same question was raised earlier about the lifecycle of unpaved roads. That gravel layer will wear off, and then possibly be replaced. Who knows what the timeline is going to be, you’d pretty much need regular surveys. Right now in that photo, it’s effectively gravel. It’s not a deep layer and it has possibly been added only to the ruts and spread from there a bit.
I have the same opinion as I have of Tislandsveien, that the road is probably not compacted in any manner resembling water-bound macadam. No trucks filled with water, no rollers. I may very well be wrong, I’m just looking at photos, I’m not an expert and I don’t know anything about Norwegian roadbuilding specifically.
You could perhaps find youtube videos of how private forest roads are built locally. If it’s anything like Finland, I would expect to see an excavator digging trenches and a backhoe or a loader carrying earth/dirt/ground/gravel as the road material. Probably the excavator would use its blade for the final grading of the surface, and it would be strong enough for cars just with the dirt, already compressed by the weight of the machines. The surface gravel might be added immediately, or after a year or two when the dirt has settled more.
I don’t have a strong opinion on how to tag ”natural compacting” as I think someone called it.
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From what I can see here both tracks are well developed with a compacted underground structure and completely covered by “hard” stuff. As such I would tag both as tracktype=grade2.
Although the underground is compacted the surface is not imo. Way to much loose gravel on top, by wich reason ever. So I would surely go for surface=gravel.
When tagging the surface I alway go for the lowest grade derived from the wiki descriptons. As you would not like to use these tracks with a scooter or a wheelchair (representing “intermediate”) my choice would be smoothness=bad.
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I’m curious to get feedback from the proponents of surface=gravel meaning entirely made of gravel with regard to tagging this particular road.
I don’t understand what further explanation you expect.
Same Topic 2.5 years ago in the German community:
The point of view that any surface=gravel or surface=fine_gravel is meant to be purely gravel – as described on the wiki – indicates to me I should not use it to tag the road in my picture, since there are obvious and significant parts that are not gravel in that sense. But I would also say that the road in my picture doesn’t qualify as surface=compacted because of the significant amount of scattered gravel on .. the surface. So I was hoping for some opinions on how to tag this road from those who think that surface=*gravel means purely gravel.
Is this realistic? Also roads with other surfaces (asphalt, concrete, ..) do not consists only of this material - they all have a compacted subsoil.
This leads also to the question: What is the surface? Often discussed also for bridges if some anti slippery “paint” changes the surface material.
It’s a fair question. I don’t have a clear answer. Maybe this is the basic question I’m asking others their opinion on.
If I ride on a compacted surface – or even a paved surface – with fine gravel scattered on top, the gravel isn’t carrying my weight, it’s merely causing me to bounce around. If the fine gravel layer gets thicker, it derails my wheel, and can make it harder to ride, but I’m still carried by the compacted base below. And if the fine gravel is even thicker, I wouldn’t even know the base was there – it could just as easily be fine gravel all the way down.
So for me there certainly is a qualitative difference depending on the thickness of the upper-most layer and the importance of the layer below in carrying my weight. At some point, the base layer becomes irrelevant to tagging?
It’s not just in Norwegian. It’s the same in English. Here’s a Wikipedia article about “gravel roads” that is closer to what we’d call surface=compacted than what we call surface=gravel. The OSM Wiki article about surface=compacted even has a picture of a road with a sign that literally says “gravel road” and warns the reader that this qualifies for surface=compacted.
This is apparently counterintuitive enough that a lot of compacted roads are tagged as surface=gravel all over the world, see this mailing list thread.
I’ve just had a quick look at the code of OSRM, Valhalla and GraphHopper. All three treat compacted as a better surface than gravel which is consistent with the Wiki. So this is not a case of the Wiki being out of step with how the tag is used and interpreted, the Wiki definition are in line with how data consumers interpret the tag.
Exactly, the mapper can only see the surface, and “surface” is the name of the key. If there’s only few loose stones scattered on top of a surface=compacted or a surface=asphalt, then I would tag that. But if, like in your example, there’s so many loose stones I can hardly see what’s below, that’s also when it starts to impact me when cycling or walking, so I would probably tag surface=fine_gravel or surface=gravel. In your example, surface=gravel. Of course, if the surface is snow or leaves then I would leave the tag alone.
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I got your point and sure, the base layer makes a difference. Nevertheless the base layer remains unvisible unless you carry some tools and start digging. We can only assess the structure of the base layer by looking at the overall appearance of the track, the shape of the flanks an the top layer.
The tag representing the complete structure is the tracktype. The more development work has been invested into a track, the higher is the rank. For more details see Confused with tracktype usage - #7 by Map_HeRo.
The surface tag describes the surface only without taking care what may be below. Anyhow a rough gravel surface on top of a compacted base would not be much different to ride with a bicycle than a rough gravel surface on a rough gravel base. In both cases a pain in the ass.
A fine gravel suface on top of a compacted base would in fact be much different to ride with a bicycle than a fine gravel surface on a fine gravel base. A track consisting of 20 cm deep fine gravel would be impossible to ride with a normal bicycle but why would anyone like to construct a track like that?
Fine gravel is more costly than the base course mixture required for a compacted track base so why would one create a track of nothing but the more expensive stuff offering a worse durability and surface stability? I have not seen such a track in my lifetime so I believe this question is theory only. I’d say this is the reason why we do not have a specific tag for such “nothing but fine gravel” tracks.
Sure, but there are people in this thread pointing to the wiki saying that surface=fine_gravel means exactly that…?
And they do exist, but like I’ve said before, I’ve never seen it on roads. Garden walkways and driveways, yes.
surface=* simply describes the surface of a track and not the track base. It’s as simple as that.
Walkways in private gardens are not my business and public garden or park ways usually have a fine gravel layer on a compacted base due to the reasons explained above. The same for private driveways - I have never seen one with more than 2-3 cm layer of fine gravel and not more than 1 cm in most cases.
If the surface is a scattered or very thin layer of fine gravel on top of a compacted layer, I’d say it’s compacted for all practical purposes. The difference it makes is if I need puncture resistant tyres or not, and this is true for the same gravel layer on asphalt (say, after the winter). Seeing as you object to the wiki’s assertion (not mine, I want to stress that) that fine_gravel means all the way down, would you tag such a road as fine_gravel or compacted?