[Tagging] navigational aid relation

[Minh Nguyen]

Vào lúc 08:29 2023-06-15, Sebastian Gürtler đã viết:
> You only would have to change the wiki page Key:entrance and encourage
> people to allow single nodes with the tag entrance=yes and addr:xyz
> (like this: https://www.openstreetmap.org/node/10979019687) if it is not
> obvious where the entrance to the property is. (What happened before for
> the whole row of houses you still can see if you plan a route to "Am
> Rehwinkel 19, Bielefeld" (from the point you are led to you don't see
> any entrance nor the house due to a high hedge, and you sometimes see
> people walking down the Voltmannstraße looking for entrances...
> Difficult, because you would have to turn in "Am Rottmannshof" to get to
> "Am Rehwinkel" ;-) )

I neglected to mention another common heuristic: the geocoder can 
automatically bias the address point toward the street named in 
addr:street when coming up with a navigable point. The Mapbox Geocoding 
API is an example of a geocoder that does this [1][2], though 
unfortunately neither Nominatim nor Pelias has a similar feature so far.

Essentially, even if the address point corresponds to a rooftop, it can 
figure out where the driveway entrance or freestanding mailbox is likely 
to be. Typically, this is pretty crude, just a matter of finding the 
point on the named street that's closest to the address point.

In your example, the entrance is on Am Rehwinkel not only because the 
address names Am Rehwinkel, but also because there's a hedge along 
Voltmannstraße. Ideally, a geocoder would compute a visibility graph to 
determine the most accessible street, blurring the lines between a 
geocoder and a router.

Then again, none of this complexity is necessary if OSM has a publicly 
accessible driveway or footpath leading right up to the building. A 
router should consider that driveway or footpath to be part of the most 
direct route.

[1] https://docs.mapbox.com/api/search/geocoding/#forward-geocoding 
(search for "routing")
[2] 
https://github.com/mapbox/MapboxGeocoder.swift/blob/10c497840c9e1142194563f402ddc903310a935d/Sources/MapboxGeocoder/MBPlacemark.swift#L446

-- 
minh at nguyen.cincinnati.oh.us