Add "mixed" as an option to the building material quest

[Discostu36]

Use case

Some building facades are made out of more than one material. For example, the ground level might have plaster, while the upper levels have bricks. SCEE users have no guidance what to select in such a case.

Photo of an example

Proposed Solution

Give "mixed" as an option resulting in the tag building:material=mixed . It is a well established value with 11.000 uses.

[mnalis]

Hm, mixed value is not documented at https://wiki.openstreetmap.org/wiki/Key:building:material which is kind of pre-requisite - probably should be added, with 11k uses, though (even if it is just 0.51% of the values). If you're author of that pic, could you crop the relevant part and upload it as e.g. CC-BY to Commons, so it can be used for the wiki (and the SCEE)?

Also, while it does kind of makes sense, I'm not sure adding it as a regular answer would be good idea (might cause more confusion than it solves - see below why).

• Perhaps adding it as Uh... / It's made of multiple materials other answer would fit better?

• While that wiki does not seem to say it explicitly, looking at wiki example pictures of e.g. loam, tiles, solar_panels etc. shows that is used even when part of the facade is not of that material, but only majority is. That is the same principle that is used in other parts of OSM, e.g. one would make building=residential even if it is only "mostly residential" (e.g. it has retail stores on the ground floor, which is quite common in some places)

  Then the solution might instead be changing the text to "What material is this building (part)'s facade predominantly made of?"

[mcliquid]

I agree with Matija's reasoning. There are also other quests that face a similar problem, where there is no option for “mixed” as a value, either. One example is the roof shape quest, which I believe is primarily about the main roof shape. Just because a gabled roof has a flat dormer window built into it doesn't mean it's “mixed” in my opinion. The same applies to the surface quest. Just because a small section of an asphalt road is covered with sett for decorative reasons, it is not a “mixed” surface in my opinion.

In the example shown, the majority of the facade is made of brick, which would be the only option for me personally. :)

[matkoniecz]

Give "mixed" as an option resulting in the tag building:material=mixed . It is a well established value with 11.000 uses.

it seems fairly bad tagging scheme

building:material=brick;concrete and building:material=mud;wood should not get the same value

In the example shown, the majority of the facade is made of brick, which would be the only option for me personally. :)

+1

[Discostu36]

Also, while it does kind of makes sense, I'm not sure adding it as a regular answer ä Then the solution might instead be changing the text to "What material is this building (part)'s facade predominantly made of?"

What I don't like about this is that the information that the building has more than one surface is lost. While this might not be a problem if the given surface applies to 95 percent of the building, I don't think it should be done if an entire floor of a five story building has a different surface.

[Discostu36]

it seems fairly bad tagging scheme\n\nbuilding:material=brick;concrete and building:material=mud;wood should not get the same value

I understand your reservations. Another possible solution would be that with "Err.../It has more than one surface material" one could enter a multiple select mode to generate a comma separated value.

[mnalis]

it seems fairly bad tagging scheme

Yeah... Also, on the second glance, it looks like majority of that 11k mixed value is likely some kind of automated edits / imports. Does someone know if those have been discussed somewhere?

I understand your reservations. Another possible solution would be that with "Err.../It has more than one surface material" one could enter a multiple select mode to generate a comma separated value.

Perhaps adding option of providing semicolon-separated[^0] value would cover most cases[^1], but I'm not sure how hard (or if at all possible) it is to change quest type while it is being asked (but if I had too, I'd guess is probably hard).

It might be doable to convert the whole quest to always be multi-answer (like e.g. recycling quest), but then I'm afraid people would click in all kind of multi-values by mistake (especially as it is a big list requiring lots of scrolling and thus finger touching)

---

So, the solutions/workarounds I see currently:

• use Uhh... / Show/edit tags and enter whatever building:material=* value one wants.
  • Advantage: already existing functionality (only needs enabling expert mode), allows for multiple materials, allows proper multiple material ordering, allows for lesser known values, allows for ATYL. I use that all the time for other quests and would highly recommend if you're not afraid of the phrase "keys and values". You'll learn few values you use quickly (or can use regular answer and Undo menu to learn - preferably with autoupload disabled)
  • Disadvantage: little more typing the first time, after that autocomplete and LRU kicks in. Requires knowing values by heart (might be made more palatable by first answering the quest to fill in main material, and then only manually editing it to add less-used material)
• just answer the predominantly used material.
  • Advantage: no need to stress the brain, quickest solution. Same as with all the other quests where we willingly lose part of the information to make the quest easily solvable in real life (building type, roof type, shop type, surface, incline, curb height, building / roof color, opening hours, smoking ...)
  • Disadvantage: some data loss, but certainly much better then nothing. It's never going to be perfect anyway -- we lack a lot of less-popular materials in the list anyway (and bundle together a few of popular more specific ones into more generic ones[^2]), and it is quite often the case that building is partly made of multiple facade materials[^3]
• hide the quest (Uhh... / Can't say / Hide; or in SCEE, long-press on quick-hide button if enabled)
  • Advantage: Fastest already existing method, avoids the brain tension if you're not comfortable with entering partially misleading data, yet don't feel like expending the effort to tag it manually
  • Disadvantage: no data gets recorded, other SCEE mappers will get asked again.
• discuss with wider community if building:material=mixed is good idea -- if yes, and it gets documented in the wiki, in could be added in Uhh... menu.
  • Disadvantage: requires work, and might (likely?) turn out it is not community supported tag.
• something else (e.g. someone familiar with a codebase comes with the explanation "actually, it is quite trivial to switch quest type mid-answering, here is a PR" - although that specific one is probably unlikely 😅 )

[^0]: that's what you meant, right? Semicolons are much more popular choice in OSM than comma. [^1]: there is the issue of lesser-used values which are not present in the list, and also a matter of ordering -- if the building is mostly brick, it should be building:material=brick;other_minor_values and not building:material=other_minor_values;brick. And that multi-select quest type does not have any way to provide ordering. [^2]: e.g. tin, copper, steel, metal_plates etc. into just metal. [^3]: e.g. even wooden building often might have lower end made of concrete to prevent rot, but I would not bother to tag them as building:material=wood;concrete. Or, if you want more extreme example, most buildings have doors/windows with frames made of plastic or aluminum, yet we do happily ignore

[matkoniecz]

just answer the predominantly used material.

another advantage is that predominantly used material is far more useful I think than say pedantic listing of wood because some extremely tiny detail is using wood

[mnalis]

Anyway, I'm tending toward clarifying the texts to say it's about "predominantly" used material.

And users (after enabling "Expert Mode") can always use raw tag editor to put any values they want if they find tagging just predominantly used material lacking and are willing to expend effort to provide more details...