Warning on building=roof

[alesarrett]

URL

No response

How to reproduce the issue?

When creating a building=roof, iD is raising a warning if a layer=1 is not entered, even if the roof is not intersecting any other feature.
Anyway in the wiki is clear that layer=1 should be used when 2 or more features overlap, to express vertical positioning. Also the wiki page for roof is describing the use of the key layer only when roof is overlapping with something else: https://wiki.openstreetmap.org/wiki/Tag:building%3Droof
So, why this requirement and warning on iD?

Screenshot(s) or anything else?

Which deployed environments do you see the issue in?

Released version at openstreetmap.org/edit

What version numbers does this issue effect?

No response

Which browsers are you seeing this problem on?

Firefox

[k-yle]

This change was introduced in #227

[alesarrett]

Thank you for the reference, but that issue pertains to cases where a highway is located behind the roof. If the warning is applied as a default for all building=roof, inexperienced users may add a layer=1 unnecessarily, which does not align with the guidelines provided in the wiki. Could the warning be implemented only when the roof intersects with an already existing highway? This would effectively draw the user's attention when it is truly needed.

[k-yle]

@alesarrett what you're describing is the old behaviour, before #227 was introduced

[tyrasd]

users may add a layer=1 unnecessarily

This is true, but that extra tag does also not create any problems AFAIK.

The adding of the layer tag was introduced because quite a high proportion of roofs are tagged with a layer even before iD suggested to add it, see #227:

Currently, 43% of roofs include layer=*

I would argue that it is in general very likely that building=roof objects have some other features underneath them (e.g. the service road of a fuel station, footpaths, vending machines, etc.). Adding layer=1 by default to roofs helps mappers to streamline the mapping of the whole situation.

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That said, for existing features, it is indeed not necessary to show the warning if there are no other overlapping features, as in your screenshot. That's fixed now with 26c1ff1: For existing roof features without layer=*, there is now no warning and the layer field will show 0 as placeholder. Newly created roofs will still get layer=1 autofilled.