location=roof or location=rooftop?

[Don-vip]

location=roof is now a popular tag.

​osmwiki:Key:location states:

• location=roof Used where a feature is located on the roof of a building.
• location=rooftop possible synonym for roof (makes it clear it is on top of the roof). Only ~30% usage compared to roof.

We currently propose only location=rooftop but roof is used a lot more:

Should we propose only roof? both? It is used essentially with power generator features.

[francois.lacombe]

Power=generator usage may come from the recent project in UK to map every single solar panel (which is a great thing)

I'd be in favor of location=roof (if you are on the roof you may be often on the top of the building)

[Don-vip]

Indeed a consequence of ​http://mcld.co.uk/blog/2019/solar-panels-in-the-uk-100000-spotted.html

[SK53]

Don-vip I asked me to comment.

The rapid increase of location=roof does indeed come from the OSM-UK's quarterly project, but a little history is in order.

Originally my first solar panels were mapped with generator:location for which iD provides a preset tag of roof. After discussion we decided that this key was redundant with location and therefore changed to location=roof. Only after a while did I notice that this key's standard preset for the same thing was rooftop. Therefore AFAIK we inadvertently introduced synonymy in the tag values, but in part this was because of synonymy in keys.

I would suggest that generator:location as a tag be deprecated in favour of location. I cannot see any gain in namespacing the tag, and the namespaces become tedious when changing a solar farm polygon from power=generator to power=plant.

I have also noticed that for both location=surface and location=ground are offered as presets by different editors (iD & Vespucci). I have probably used both for solar panels mounted directly in the ground. I think the latter is preferable (surface would also be valid if the surface was a building roof, so it has some inherent ambiguity).

I suspect that at least one other tag in use with solar panels may be alternatively represented with a more widely used tag (generator:orientation and direction), but total number of instances is much smaller in that case.

Thanks for the detailed attention shown here.

[Don-vip]

In 15372/josm:

• fix #18153 - prefer location=roof over location=rooftop, location over generator:location
• update TLD from IANA
• ignore cycling network tags icn[_ref], ncn[_ref], rcn[_ref], lcn[_ref]

[Don-vip]

Thanks for the comments!

[Don-vip]

In 15373/josm:

see #18153 - fix mapcss selector

[francois.lacombe]

Thanks SK53 for the comprehensive comments