[Tagging] Tagging proposal On Wheels app 3 - Parking spaces for wheelchair users

[Tobias Knerr]

On 14.05.23 at 19:59 Yves wrote:
> everybody is not super accurate in drawing polygons, imagery has a resolution and I doubt a lot of mappers go trough a complete parking lot a measuring tape in their hands.

Sure, mappers drawing polygons very rarely use measuring tape.

The same is true for mappers adding tags.

I'd wager the vast majority of width values currently in the OSM 
database are estimates or – at best and in rarer cases – rough 
measurements from a phone app.

It's obvious that the dimensions of polygons in OSM are not reliable. 
But unless you have a plan to prevent mappers from entering guesses or 
insufficiently precise measurements into width tags for parking spaces 
(even while using those sources for width tags on all sorts of other 
objects is accepted practice and commonplace), I doubt that you will 
consistently achieve the desired accuracy by encouraging people to add 
width tags to parking spaces. _Maybe_ it will work as long as no one 
except accessibility-focused apps uses this tag and therefore mappers 
overwhelmingly keep that particular use case in mind when adding the 
tags, but that seems fragile.


Also, on an unrelated note, I'm curious about the intended definition of 
width and length for non-rectangular parking spaces.