Hello,
In some places as train stations or airports abroad, there are public pianos where people is free to stop and play. During the Italian Foss4g meeting, I noticed there was a public piano along a university corridor. Some small bistrot have pianos which can be played casually by clients.
I tried to find some of them already mapped in OSM but did not find anything. Did someone already map them in OSM somehow? If not, how would you suggest to tag those places?
Alessandro
Thanks for this suggestion.
Unfortunately, I do not know how to map such a public piano, but I think it’s a good idea to include it in our database.
Hi Alessandro, welcome to the OSM forum! 
There seems to be amenity=piano. While the tag isn’t by any means officially approved, it seems to be the most common one and it has some (recently created) documentation.
I thought we are mapping permanent/semi-permanent things? Do pianos count?
There’s plenty of comedy on how hard it is to move pianos, so I’m inclined to say yes. 
More seriously, a mapper should of course use their common sense to judge how likely a piano is going to stay available in this location to avoid disappointment for future visitors. But I wouldn’t categorically rule it out.
Thanks for the info guys!
Kucai, the piano at the Tiburtina railway station in Rome is there for some years so we can consider that almost permanent. The motivation for mapping is that I see it as an important cultural resource for our towns, and OSM is the opportunity to localize them (supporting for example a traveler who wants to play the piano while traveling).
Tordanik thanks for the link, amenity=piano is a good start and there are already several pianos mapped and open piano maps are already online! For ones in big public spaces as railway stations, a point with amenity=piano (at the right layer) just works.
How can we deal with pianos which can be played in small shops (i.e. I saw one in a bookstore, another one in a Bistrot). In this case, it would be more a service offered by the place than an independent amenity entity. Is that ok to attach the piano amenity to a shop or is there a more correct way to map that? How to map one public piano which is in a restaurant (amenity)?
For the record I left a comment on wiki discussion page.
Would be easier if the shop/restaurant is already mapped as an area.
If not:
Perhaps you can add the relevant address identifying the shop, and access=customers to the amenity=piano.
A piano=yes (exactly 1 instance) should be simpler. In contrast, the original author in https://github.com/brunetton/OpenPianosMap might have musical_instrument=piano in mind, adopted from shop=musical_instrument
That being said, there’s nothing preventing you to add a amenity=piano tag to a shop=*, without key conflict.
Thanks Kovoschiz!
I started to map the public pianos I know in my city. Until now, the amenity tag clashes only in the case of a piano in a restaurant, but mapping the piano as a distinct node and specify operator= with the name of the restaurant seems a workable solution. I have found that for example priceless map understands this scheme and gets the piano mapped correctly (among objects of utility) in the restaurant indicated by the operator key of the piano node.