How to tag the surface of highways that are compacted crushed limestone

This question arose in a changeset discussion . The roads in question are built by laying down crushed limestone and then compacted, both by construction vehicles and also by traffic. Due to the nature of the materials, the surface becomes hard and smooth (This and this photo from wiki are good examples). The discussion point was whether to tag the highways with surface=compacted and some sort of additional tag such as compacted:material=crushed_limestone (in a similar pattern to surface=paving_stones,paving_stones:material) or whether a simple tag of surface=crushed_limestone would be simpler way to convey the same information.


I think for the user it is more important to know what the road “feels” like rather than what exact material it is made of. So surface=compacted seems to be the best choice.

surface:material=* is used over 800 times already, so maybe use that for the additional information instead of the unused compacted:material=*?


If it is surface=compacted then inventing endless parade of new tags seems a poor idea.

Also, surface=crushed_limestone could be describing other, lower quality surfaces.


I agree that in this case surface=compacted because based on the OP’s description, it sounds like machine compacting was part of the construction process. However, I have seen some mappers use surface=compacted where the surface of a road or path has simply been beaten down by use. We have some 4x4 only roads around here that would be considered “compacted” by that definition. Machine compacting leads to a mostly uniform, stable, and smooth surface. As the wiki states “best sort of ways below paving…”


In this particular case, the mapper making the changes is mapping every day without taking a break, making a large number of changesets, many of which are minor tag changes of questionable value. Some of the larger changesets are edits using Level0, which doesn’t provide the mapper with a way of reviewing the changes against external sources.

I think this falls under the category of undiscussed mechanical edits.

@SomeoneElse, does this pattern look familiar?

Edit: That’s some 87k changesets (90%) using Level0, also discussed in OSM US Slack.


Definitely sounds like surface=compacted to me and tagging additional details about the material used via ATYL compacted=* also seems fine for now. If consensus emerges that surface:material=* or compacted:material=* is preferred, then these tags can be changed. I would expect surface=crushed_limestone to mean loose crushed stone much like surface=gravel or surface=fine_gravel. That’s a different meaning than surface=compacted so I consider the mechanical edit unjustified.


I’m sure if you look far enough through changeset discussions you’ll see a few comments from me too :slight_smile:

These sort of “gardening” edits take place on a spectrum between 100% beneficial spelling corrections (highway=pirmary etc.) and 100% harmful removal of information. What you’ve said on is entirely reasonable; it makes sense to talk about it.

I did say something like the above before.


Add a little water and mix and you got a plastine cement like surface frequently used here to (long term) repair subsided roads or used as rims to stop rainwater running off the sides, saturating the soil slopes downside of the hill causing the next landslide. In a car ok, on a bike with the often developing humps and bumps a trial.

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Thanks @jumbanho for posting the question here. It seems the general consensus is to have the focus on the “kind of surface” rather than the material. I’m perfectly fine with this, but it seems that actual usage of the tag doesn’t reflect that.
As @Shaun_das_Schaf proposed, I’m also in favor of a having one tag to describe all surface materials instead of many different ones. surface:material will be useful in combination with surface values like cobblestone, gravel or even metal.
Let me suggest to include this more clearly on the Wiki page. The current description describes materials and type of surface more or less equally. Maybe we should take this discussion also as a good reason for looking through the other 8483 (!) values of ‘surface’ and get this a bit more streamlined.

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And a few remarks on what is entirely off-topic in this thread:

The large number of changesets lies in the nature of the type of edits I make. I mostly edit single objects with a single tag with a spelling mistake. If these changes are of “questionable value” - what is the value of an OSM database with mispelled tags that no tool will ever be able to understand?

How did you find out that I’m editing without consulting other sources like changeset comments, history of objects or aerial images? All this information is just one click away, even if I do the final editing in Level0.

I have no idea what this links to, there’s no way to read anything without having an account there. Please provide us with an accessible link or a copy of the content.

To be fair, this block was because I changed “openining_hours” to “opening_hours” on 8 nodes which in hindsight turned out to be test edits by some obscure new tagging software - which you wanted to (fully correctly) mention in a changeset comment instead of a block.

As Andy has said, some of the some of the spelling corrections and obvious tag repairs are absolutely beneficial. I do support that and I hope it continues.

However, some conversions of tag keys and values from one form to another seem to be questionable. As the discussion in this thread has shown, it is helpful to have the conversation about these changes with the mappers involved and with the broader community. Hopefully before the changes are made, rather than after them.

To me, the deletion of potentially valuable information from the map, as in Changeset: 139181247 | OpenStreetMap or Changeset: 139181328 | OpenStreetMap is also a problem. @mueschel , I would ask that you take the time to consider changes like this carefully and contact the mappers involved before deleting tags that may contain useful information. In particular, if the changes relate to a broad group of tags, even if those tags are rarely used, I think it would be best to propose the changes here for discussion first.

I suggest the following be added to the wiki for key:surface:
“The surface=* tag is about the kind of surface, not necessarily about the specific material. While some values imply a material, e.g. surface=concrete, others such as surface=gravel do not (the gravel could be composed of limestone, granite or several other specific types of rock/material).”


The surface wiki page is already pretty clear that the key is not specifically about material, though perhaps some wording could be improved. It says:

Describes the surface of a feature

used to provide additional information about the physical surface of roads/footpaths and some other features, particularly regarding material composition and/or structure.

It doesn’t say “used to record the surface material” and leave it at that. “…and/or structure” is doing some heavy lifting here. Many of the surface=* values do indicate a specific material, but they also indicate a certain surface treatment, style, or construction type. Other values indicate a type or style of surface which can be constructed from several different materials. surface=paving_stones is a clear example of the latter as they can be made out of real stone, concrete, brick, or perhaps even some other material. We can indicate which one with paving_stones:material=*.