[Tagging] navigational aid relation

[Minh Nguyen]

Vào lúc 00:26 2023-06-14, Florian Lohoff đã viết:
> Management Summary:
>   In navigation/routing the point the router is routing to is the nearest
>   point on the routable network from the poi/address we like to navigate
>   to. The nearest point may not be a location where the address/poi can be
>   reached from.
>   I suggest a navigational aid relation hinting the link between
>   geocoding and router to use a different point on the routable network.

I agree that there is a need for geocoders to produce more 
routing-friendly locations than the centroid. Navigable points are 
nothing new in the field of location services. Most geocoders already do 
this, including some that are often used with OSM-based maps, although 
none are open source as far as I can tell.

I've written something of a white paper on the subject of navigable 
points. [1] The short story is that most scenarios would be well served 
by micromapping in OSM combined with some clever heuristics in the 
geocoder, without the need for a new relation type. I've provided some 
example OverpassQL queries to prove the concept, but in reality a 
serious data consumer would perform spatial queries or traverse the 
relation hierarchy more directly, without the help of a separate API.

With this heuristics-based approach, we can take advantage of the large 
and growing body of data that's implicitly optimized for routing. 
Mappers generally wouldn't have to familiarize themselves with routing 
engines; they can just map what they observe, but in greater detail.

When none of the heuristics applies, the last resort can be a site 
relation, using each relation member's role to clarify why the 
application might want to present the member as an option. I've used 
site relations in a few cases where a spatial query won't turn up any 
useful results.

For example, a nearby American football stadium [2] has multiple parking 
lots, but all of them are off-site, on the grounds of an amusement park, 
a college, and some office parks. A driver would only be interested in 
the parking lot that corresponds to the ticket they purchased. The 
parking lots are members of a site relation with the stadium. [3] We 
have no hope of precisely modeling ticket classes in OSM, but the 
application can simply list the lots by name and let the user choose 
manually.

Unfortunately, I'm unaware of any OSM-based data consumer that 
implements these heuristics, but routers aren't the only reason to map 
building entrances or site relations.

[1] 
https://wiki.openstreetmap.org/wiki/User:Minh_Nguyen/Navigating_between_entrances
[2] https://www.openstreetmap.org/way/296503400
[3] https://www.openstreetmap.org/relation/14507813

-- 
minh at nguyen.cincinnati.oh.us