individual piece of gravel: not
gravel, especially with smaller pieces mixed in: yes, it can be compacted
(I would design surface= values differently, but not for this reason)
Did anybody postulate that?
Individual pieces are not compacted but overall mixture can be.
When mixture being compacted includes gravel it gets tagged as compacted
I do not see any gravel in these pictures:
- File:Road surface made of limerock, Gilchrist County, Florida.jpg - OpenStreetMap Wiki
- File:Very high quality unpaved path 20220618 181105.jpg - OpenStreetMap Wiki
Do you?
I took myself File:Very high quality unpaved path 20220618 181105.jpg - OpenStreetMap Wiki and it is a highly compacted gravel.
Another take of this built, at terminal location, where you can see larger pieces forming this also visible:
See also
and yes, it is not a concrete.
I expect the same applies to other one. Limerock does not come in form of clay or in form of gigantic flat pieces. It is also a compacted gravel.
When I think about surface=compacted, I assume the highest grade of unpaved surface locally available. That is, roads intended for regular traffic. It looks like this when in pristine condition, and can support any normal traffic in any normal weather:
There may be varying amounts of loose matter on top, but the main surface, when intact, is solid. Almost like asphalt. You would need tools to remove any part of the surface.
This is gravel in the OSM sense of ”ballast rocks” compacted together with finer materials:
This is a temporary surface only created for the ongoing work on the powerline. If this were also called compacted in OSM, it would basically make the value meaningless.
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I have to say, that the last image is (for me) a clear example of a surface=compacted for a couple of reasons.
First: It is a mixture of different sized material which are compacted together.
Second: The surface (through compaction) is so that it does not move under load (walk/bike/drive). The last point is for me an important feature to decide between compacted and (I guess in this case) gravel. I don’t expect a compacted surface to move/shift when I walk/bike/drive on it.
Those rocks are not quite that stable.
But in any case, if these two roads would use the same surface key, it kind of makes surface classification useless for determining road condition. Might as well just use unpaved and stop worrying about the details.
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It is hard to tell from the picture. I would say at least the part where the wheels are the surface looks pretty firm. But also: road condition is not conveyed by the surface tag that’s what smoothness is for.
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You’re kind of completely ignoring the “water-bound macadam” part of the definition though.
But again, I’m not saying anything about smoothness here. I’m trying to point out that if you simply take the dictionary definition of compacted, the tag value compacted becomes utterly meaningless.
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I am not sure what you mean by ignoring “water-bound macadam”. Yes this specifies a certain type of construction method with layers. But at least the German Wikipedia article suggests that the original method of construction is basically obsolete and not used anymore and that the definition has changed. Additionally the OSM wiki in the definition for gravel provides a wide range from track ballast to compacted roads.
(Independent of your example) For me personally the fact that the surface is pretty solid and does not move/shift when a load is applied is an important feature for a compacted surface - independent of the exact construction method.
For the image above I would not correct it if it was tagged as a gravel road but I personally would not do so myself.
Also I think for this the regional context is important.
What would you say, when the documentation of compacted was less about gravel, but e.g. minerals of varying size, ranging from the finest particles (clay, silt, loam) to bigger pieces, visible with the eye as individual pieces? That in order to describe “compacted” as a material, not a firmness?
I still do not understand why @Mateusz_Konieczny repeatedly told me, that an individual piece of gravel cannot get compacted - who ever said that? Doing so would be plain ridiculous! All the while failing to understand, that a mixture of different size pieces cannot get compacted when missing theses very fine compounds – those that are not discernable from plain looking at the ground but instead require to touch the ground with ones fingers? BTW: These sorely missing from the lower picture above!
In What makes a surface "compacted" - #21 by Mateusz_Konieczny I quoted specific message to which I was replying.
The message was
and I was trying to make sense out of it.
(1) gravel of roughly uniform size without smaller particles can be compacted - and it is a typical step of building roads, see say https://www.youtube.com/watch?v=PCW4GPkndJU
(2) in areas with soil, where you dump gravel onto it: you will get soil anyway as smaller particles (often happens on highway=track)
about What makes a surface "compacted" - #26 by Mateusz_Konieczny ? That it still 100% fits
and from this photo ot looks like this surface would do this, it does not look like properly compacted surface
at least both are clearly better than surface=sand
Did you actually look at the video?
Yes, I did watch video. Why I would post video without watching it.
If you think that it does not indicate what I think it indicates, can you expand a bit?
It’s late here, I expand, see picture below:
These are boxes, labels transliterated, “0-16”, “16-32 Rollierung”, “30-63 Rollierung”. There is a conveyor belt on the top, running from L2R, presumably there are sieves sorting the material put on that. The numeric values presumably taken from the sieves, the piles in the boxes quite telling, just my personal observation, but observable on the photo. The “0-16” is approximately what is “compacted” in the video with a vibrator plate (the video shows a much more defined 0-… mix, from the looks of it wholly from limestone, my shot on location arbitrary minerals). The other two boxes nn-…, some call them gravel, some call them rubble. Not in a mood to link to respective definitions in the wiki documentation. Only one of these materials can be “compacted”.