[Talk-us] Exactly what does an address correspond to?

Toby Murray toby.murray at gmail.com
Wed Jan 25 01:34:22 GMT 2012

On Tue, Jan 24, 2012 at 3:22 PM, Nathan Edgars II <neroute2 at gmail.com> wrote:
> Presumably the answer is "a mailbox". But we generally map buildings and
> properties long before we map mailboxes, and when used as a location one
> expects an address to be the actual location the mail is intended for, not
> the location of the mailbox (which may be e.g. out on the main road or in a
> central location).
> So back to the original question: exactly what should an address correspond
> to in OSM? For example:
> *A large resort hotel with one address for the main building/hotel as a
> whole and others for individual buildings.
> *A mall with one address, but some large stores have their own addresses.
> *Two office buildings that share an address.
> How do GIS professionals usually handle these issues?

I've had this question before too. For perfect routing the ideal
situation would be to have the address tags be on a node at the exact
location that you want routers to route you to. So the front door of a
house or the main entrance of a store. Of course that often doesn't
work. Multiple entrances and special purpose routing (to the loading
dock?) for example.

I see two different cases really. For residential addresses which
usually stand on their own, I tend to put the address on a node by the
door or stairwell for apartments. If you search for my address, it
will take you to within inches of the first step of my stairwell.
You're on your own to find the apartment number :)

I don't think postal services will never use OSM so I don't see the
location of mailboxes as being very important.

For "real" POIs like shops and such the address really needs to be on
the same object that has tags that describe whatever it is. That way
you can click/tap on a POI or search for a business name in nominatim
and see that Fred's Barber Shop is at 123 Main Street. For places that
are mapped as a building or POIs inside of a building either nominatim
or routers (or some combination) should probably look for
entrance=main/yes nodes along the perimeter and route to there by

That's still not always clear though. With your examples: Does the
address go on the area defining the entire resort or on the main
building? I would probably argue the main building since that is where
you will usually want to end up when routing. Especially if individual
buildings have their own addresses. But then you may have to duplicate
name and other information on the land area and the building. And then
which one will nominatim find first?  I'm sure someone has thought of
a way to use relations for this but... meh

The mall example doesn't seem too hard. The mall and shops within it
can have their own addresses. Again, look for the nearest entrance=*
tag for routing purposes. And I suggest entrance tags to solve this
problem: http://mapq.st/Ak9fC3 - Clearly the starting point is
ridiculous. It is just finding a routable way that is nearest to the
centroid. I suppose if the inside of the building were mapped...

I would think that sharing an address would be fairly rare. Most
places at least have unique suite numbers, don't they? (which I map as
addr:suite even though it isn't used by anything yet)

I think county's GIS office associates addresses with land parcels so
that's not very helpful for OSM.


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