[Tagging] navigational aid relation

[Martin Koppenhoefer]

Am Sa., 17. Juni 2023 um 21:48 Uhr schrieb Minh Nguyen <
minh at nguyen.cincinnati.oh.us>:

> You're quite fortunate that the meaning of an address is unambiguous in
> Italy. At least you can be sure that a pedestrian route will lead to the
> main entrance, even if other modes aren't as well-served.



actually the real situation in Italy is more complicated than the theory.
For one, because the reality doesn't always follow the legal prescriptions
(every entrance to a building or site should get a housenumber according to
the law, i.e. also small gates leading to the garden, or similar), but
sometimes no housenumber is posted (maybe not assigned, maybe not displayed
by the owner, but either way not compatbile with the law), and sometimes,
"old" housenumbers (where there used to be a door but is now closed) are
still posted. And the law also declares that "potential" entrances should
get their own numbers, this refers mostly to shop windows, i.e. many
housenumbers are not assigned to a place where you can currently enter the
building/site.

As a result, many businesses and homes have more than one housenumber.
Adresses always are assigned to points and never directly to buildings
(although one could say a "buillding has several housenumbers" if you look
at the collection of numbers that lead to the building, and POIs usually
either indicate a of their housenumbers, or use the one that is actually
usable,  or sometimes use one that is now a closed door (e.g. because it is
their official address where they have registered the business).

You cannot assume that where a housenumber is posted this means access for
pedestrians, because "vehicle only" access points also get housenumbers
(AFAIK).


Here in the U.S., the meaning of an address depends on who's using it.
> To the tax authorities, it refers to the whole parcel. To emergency
> responders, it's either the building or the beginning of the driveway.
> To the postal service, it's the mailbox, which can be at the door, at
> the street curb, or even at the neighborhood entrance.
>


This is probably how these are effectively interpretated / used. If the
number refers to the whole parcel (tax), isn't this then a valid point of
view for emergency responders as well? Won't they help you on every spot of
the parcel, or do they require you go either into the building or to the
beginning of the driveway before they will rescue you?



>
> Mappers here generally treat the address as an attribute of a building,
> POI, or something else. [1]



in Italy, we also treat the address as an attribute of a POI -
additionally, because from all the possible (assigned) addresses, there
will often be a principal / official one which the business uses in their
communications (this is somehow disputed in the community, some people do
not want to "duplicate" addresses, so they add the poi information on the
entrance node, which is not fully correct obviously, because the POI is
usually inside and not on the perimeter, and the entrance is not the same
as the POI so it goes against the one object one element rule. We never use
addresses on buildings though.



> So the address point's coordinates don't
> necessarily have any relation to where you would navigate to.



IMHO this is a problem, the addresses we add should indeed have a relation
with where they are assigned to. A postbox with an address that is not on
the site where the address belongs to, should not get "addr:*" tags of the
far away place. There is "contact:street", "contact:housenumber" and others
to add addresses that are elsewhere, as referers.



>
> This is another good reason why I'd advocate for objectively
> micromapping features that data consumers (whether routers or geocoders)
> could recognize as navigable points or not, depending on the situation.
>


+1

Cheers,
Martin
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