Add shells as a surface option

[rhhsm]

Use case When surveying in the Netherlands, I had a need to be able to choose "shells" as a surface option for (foot/cycle) paths.

Proposed Solution Add the "shells" option for surfaces, at least for paths. There are 20 options available now, so there's place for one more without adding another row. Although the geographic scope of use is limited (NL and US east coast), I think it is the most frequent option not offered yet that is not a duplicate of an even more frequent surface. This photo could be used (I have more)

[westnordost]

Too rare. You can leave a note.

[rhhsm]

I think the question should be what to use the remaining free spot in the 3x7 matrix of surfaces for. It's not rare in NL.

[westnordost]

You are welcome to do research on that via taginfo and report the result in the discussion forum.

[PanderMusubi]

I think is covers it but the definition should also mention shells perhaps https://wiki.openstreetmap.org/wiki/Tag:surface%3Dchipseal

Another example is https://asfaltwinkel.nl/media/attmgipx/jlousberg_20210223_asfaltwinkel_nl_r1_4244_print.jpg?height=600

Online hard to find pictures of but the Netherlands is full of these asphalt walkways with a shell top layer, hence unsuitable for roller skating e.g.

[mnalis]

@PanderMusubi There are many asphalt surfaces that are unsuitable for roller skating (or even for bicycle driving!).

• v39.0-beta1 contains #1630 which should allow you to map that fact.

[PanderMusubi]

Thanks, that is indeed a good additional quest.

[Derkades]

In the Netherlands, it is a common surface in natural areas like forests and parks. Please reconsider adding it!

In this overview the frequency difference of surface=shells between the Netherlands and other countries is clear. I suspect the tag would be much more commonly used if it was available in StreetComplete.

I usually tag it as compacted when it is a fine and firm surface that is easy to cycle on. Though now that I think about it, it would be better to leave a node rather than tagging with a value that fits best but is still not entirely accurate. I see it is also frequently tagged as gravel and fine_gravel by other mappers.

In case it is useful, here is another picture, of a finer type compared to the original post:

(public domain)

[rhhsm]

Note that in the Dutch SC translation of "fine gravel" (Fijn grind, fijn gravel, schelpengrit), this surface is included. Translated by Peter, 3 years ago. If the Dutch OSM community has consensus that shells= fine_gravel, we can leave it at that.

[PanderMusubi]

In the Netherlands, those shells are also mixed with asphalt. So there are several surfaces:

• loose shells
• compacted on dirt road
• mixed in asphalt top layer

[mnalis]

So, I'd say:

• loose shells => surface=fine_gravel
• compacted on dirt road => surface=compacted
• mixed in asphalt top layer => surface=asphalt or surface=chipseal[^1] (with perhaps asphalt:type=*, not taggable by regular StreetComplete, but a note may be left)

All of them could/should be more detailed with smoothness=* (in "Surface quality" quest, disabled by default)

[^1]: see https://github.com/streetcomplete/StreetComplete/issues/4265 & https://github.com/Helium314/SCEE/issues/561