StreetComplete begins asking for the placement of fire hydrants. In urban areas, I mainly see fire hydrants (pillars) located DIRECTLY behind the end of sidewalks or streets. The hydrant may actually be on ‘green’ land but is to be operated from the street/sidewalk.
How should the placement be tagged?
fire_hydrant:position = green? Even though I don’t have to and might even be unable to step foot on the ‘green’ - as it is intended to access it from the street/sidewalk?
fire_hydrant:position = sidewalk/lane? Even though it’s placed not ON the sidewalk/lane?
To me, the fire_hydrant:position key is meant to indicate where the body of the fire hydrant is located, not where it’s operated from. So for instance I would tag one fire_hydrant:position=sidewalkif the body of the hydrant is located directly within the walkway, within the space intended for the use of pedestrians to walk; to indicate that a ‘pillar’-type hydrant is a hazard to someone walking, that they have to walk around it. (Or the cover plate of an ‘underground’ hydrant could be expected to be walked upon.)
Whereas fire_hydrant:position=green I use if the hydrant body is in any ‘green’ space (grass, a decorative flower bed, or whatever). By inference such a hydrant is not a walking hazard, and a pedestrian doesn’t have to concern themselves with it.
Your example is quite literally “an edge case”. I would tend to lean toward fire_hydrant:position=green because the body of the hydrant isn’t within the walkway, and a pedestrian doesn’t need to walk around it.
(I personally would scarcely ever use fire_hydrant:position=lane, but I would only use it on hydrants where the body is located in the roadway, i.e. a car would normally drive right over it. These aren’t really a ‘thing’ in Canada as you would only ever really see these with a fire_hydrant:type=underground, which are unheard of here.)
I was unsure if the ‘routing’ aspect (walking around the pillar) or the ‘emergency response’ aspect (direct access, not searching for the hydrant somewhere on the green (in the bushes)) takes precedence. I will follow your suggestions.
To me fire_hydrant:position=* is all about the physical location of the body of the hydrant, not where it may be operated from, because access to a fire hydrant is always “direct”. An emergency responder wants to know where the hydrant is located, not where it may be operated from, because regardless of its location firefighters will have direct access to it and space around it to connect hoses and operate the valve. A hydrant placed in a “green space” will still ultimately need to be operated from the sidewalk and/or street, because after all: that’s where the fire truck will be!
As already written a fire hydrant should always be accessible by the firemen and there is always a “fire hydrant sign” which must be visible. If you can’t find the hydrant yourself, the sign guides you towards it.
Not quite on topic, but we’ve had the case of fire hydrants being deleted because they were underground and SC didn’t account for that, don’t know if that is fixed, but it is definitely somethign to be careful about.
In the “Does this still exist?” quest, we display the type of the object in question via its iD tagging preset. Specific presets for pillar / underground hydrants were added in #1160 (released in id-tagging-schema v6.8.0 on Aug 19, 2024). The first StreetComplete release after that (v59 on Sep 18, 2024) should have included that distinction.
Do you remember which OSM objects that impacted? Then we can find out which StreetComplete version that user was using, or maybe if there was a different kind of confusion.
How do those signs look like in Switzerland? Is the fire hydrant diameter listed on them like in Germany and some other countries? If so, then StreetComplete’s fire hydrant diameter quest could maybe be adapted and enabled for Switzerland as well.
Keep in mind, they don’t have to be on the hydrant itself. I actually found some cases here, where the hydrant is way more visible, than the sign. (hydrant on the border of the street, but the sign was on the house 5m inside the access road for it)
But I couldn’t find the regulations about it. Maybe it is different for each canton..
Then the sign showed a 5 at the bottom.
The (large) number at the bottom of the T is the distance of the water connection to the sign (i.e. 7.7, 7.6 and 8.3 m in the first image), the number at the horizontal bar of the T is the distance of the hydrant to the left or right of the sign (i.e. 0, 1.4 and 0.2m in the first image). It might be a normal hydrant, or a so-called Unterflurhydrant.
Edit: Just because I walked past this close to home, here are two (slightly) redacted photos.
I think I didn’t check it enough. So most probably the sign is only necessary for underground hydrants. And the sign on the pillar hydrant on my photo doesn’t correspond to itself, but to another connection in the vicinity…
I would tend to lean toward 
