Expands quests to observation towers

[paulklie]

I believe the following quests could be extended to the 26k observation towers:

Things overlay:
Currently leisure=bird_hide can be added via the things overlay. An observation tower feels quite similar to a bird observation place, so I think they should be addable to.

AddStepCount:
Currently only 189 observation towers have a step_count set, but it is suggested by the wiki. I have never seen an observation tower that does not have steps. Useful for people with limited physical capabilities,

AddGeneralFee:
In my experience the majority of observation towers are free, the current stats show fee=yes 209, no=450. Additionally users are unlikely to encounter multiple observation towers since they are sparse I doubt this would be spamy.

AddWheelchairAccessOutside:
Am not quite sure if it would better fit into the AddWheelchairAccessBuisness quest. Currently 88 towers have wheelchair=yes, while 831 have wheelchair=no.

AddOpeningHours:
The vast majority of free observation towers are open 24/7, thus I would limit this quest to fee=yes towers.

[westnordost]

Things overlay

No, structures are explicitly excluded from Things.

The others: Sounds okay. Maybe some strings need to be updated?

[paulklie]

No, structures are explicitly excluded from Things.

Hmm, but arernt shelters, hunting stands, (most) toilets, fire lookouts and wildlife hides also all structures? What differentiates them? Would this maybe fit better into the "places" menu?

[westnordost]

Maybe, I don't remember why I added them, must have been a close consideration whether to include them or not. Aren't there comments or something for these?

[matkoniecz]

StreetComplete/app/src/commonMain/kotlin/de/westnordost/streetcomplete/osm/Things.kt

Line 7 in 3dc1b77

fun Element.isThingOrDisusedThing(): Boolean =

has comment

 *  To demarcate this category from others, the following are not included:
 *  - structures that are big enough that they would rather be classified alongside buildings
 *    (e.g. water towers)
 *  - permanent features of the landscape (e.g. geysers, peaks, springs)
 *  - things that are features on other map features that wouldn't make sense on their own (e.g.
 *    crossings, traffic lights, entrances, golf holes)
 *  - things that should not be mapped as points - even if allowed - and landuses (e.g. car parks,
 *    dog parks, playgrounds)
 *

there may be discussion in #5373 #4912 https://docs.google.com/document/d/1tcLm0EDWoCBdkq1N0pKebtksJcF2vMtUgKc9h96fuF0/edit?usp=sharing but I have not found it at the first look, I see that towers are mentioned and rejected in doc

See also #5892 for similar consideration

I am not opposed to borderline things appearing in both overlays