[cuonic]

On the other side of the Channel, the French government has managed to create the "BAN" (Base Adresse Nationale - National Address Database), a database of detailed postal addresses in the country along with precise GPS coordinates: https://adresse.data.gouv.fr/base-adresse-nationale

On top of the database they have provided an interface to view the data, interfaces for towns and cities to keep the data up-to-date, free APIs to search addresses and performing geocoding or reverse geocoding (https://adresse.data.gouv.fr/api-doc/adresse) and the data is openly licensed and available to download.

Feeding the BAN has been enforced by law, localities are required to put together and upload their "Base Adresse Locale" (Local Address Database)

The original data was obtained from multiple sources, including "La Poste", the French Royal Mail equivalent, and OpenStreetMap !

[gabesullice]

A cautionary example of how data meets reality…

My address in France is listed in the BAN… but only to the granularity of my street number (e.g., 123 Main St.).

Unfortunately, that number corresponds to at least 7 different structures, 5 of which are apartment buildings.

Of those 5 buildings, each has multiple stairwells with their own door and no line of communication between them—they might as well be separate buildings.

My particular building has 8 levels with 2 flats per level. No flat has a door number or letter, meaning I must say 'Nth floor, door on the right' to give directions to a visitor. And I could not receive mail until I affixed my name to my postbox on the ground level.

None of that is in the BAN as far as I can tell.

Finally, on OpenStreetMap, the coordinate for the the street number address in the BAN actually corresponds to an island in the street that happens to face a private road that enters the property. There is more than one entrance :)

[Propelloni]

This sounds like bad design by the property developer and a sloppy building authority. The first is corroborated by the lack of unit numbers. Who does such a thing?

The BAN actually only tracks down to the plot level, so I assume all your structures are on the same plot. From there on it is the building authorities job to check building plans and to enter the substructures into the cadastre, where they are usually lettered. It's the developer's job to mark the buildings and entries. Sloppy work, all around. So sad.

[gabesullice]

You could be right, but I think it's a little beside the point.

The challenge illustrated in the blog post is that it's practically impossible to build a really accurate address dataset since the real world is messy for the reasons you listed. Just like falsehoods programmers believe about names [1], you shouldn't put much faith in anything that claims to normalize addresses either.

As other commenters have said in the replies, my situation is not uncommon in Europe.

As they say, 'the map is not the territory.'

[1]: https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-...

[wongarsu]

As long as it shows that your address corresponds to that plot of land it's still a perfectly accurate address dataset. Your address just kind of sucks. That doesn't make the dataset less accurate, just less useful.

Still a lot better than some other parts of the world though. In Asia you sometimes have addresses that boil down to the nearest landmark and a phone number for the mailman to call

[gopher_space]

> it's practically impossible to build a really accurate address dataset since the real world is messy for the reasons you listed

Different entities will have orthogonal needs when it comes to your address. First responders want a door, the post office wants a mailbox, assessors want a plot number, etc.

[marcosdumay]

Yes, but it's not reason creating such database, or for not using the standard one from your place.

[Propelloni]

Good saying!

[cameldrv]

I don’t know what’s usual in France, but it’s usual in Germany for apartments to not have numbers. You have to put your name on your mailbox, and there’s no way to address something to someone who doesn’t live in the apartment. If you’re filling out government forms, you sometimes have to put in something like “third floor left side” so they know where you actually live.

[jll29]

Britain also has "dwelling designations" like "3FL" (third floor left) commonly used to describe unnumbered flats (which may well have numbers or not). I suspect this way of referring to flats is unofficial, but it is commonly seen on letters.

[growse]

Same in Iceland I think. No name on the door? No mail.

[dhosek]

Costa Rica doesn’t have numbers on the buildings, and many streets lack street signs, if not names. You’ll have addresses like “50 meters north of the old church” or “behind the banana stand.”¹

[myriadoptimum]

Depending on where you are in France (especially places with lots of housing stock being older buildings), it's common (if not the norm) for there to be no unit numbers and to direct people to apartments by floor number / door position relative to stairwell.

[wongarsu]

That doesn't surprise me, same thing in Germany. However having multiple buildings with the same house number (without distinguishing letters) sounds like the much worse oversight here

[taejo]

Though at least in Berlin it's pretty common for multi-family houses to have a separate wing (Seitenflügel) or rear house (Hinterhaus) that are reached by entering the street door of the front house (Vorderhaus) and then exiting through a door behind the staircase into a courtyard before entering the second building, and at least in some cases each building has its own set of mailboxes, all with the same address.

I regularly have the problem that deliverers don't read my delivery note and don't listen to what I say on the intercom, and go all the way to the top of the front house before realising I'm in a different building altogether.

[postepowanieadm]

That may be because Code Civile allowing(used to allow)((par 664?)) ownership of floors.

[immibis]

> the lack of unit numbers. Who does such a thing?

Everyone in Germany. Units are identified by the surname of the person who lives there. If there's more than one person living there, too bad, pick one or write them all.

[scotty79]

> The first is corroborated by the lack of unit numbers. Who does such a thing?

The entire country of Germany for example. It's super annoying.

Although they have the decency to assign distinct numbers to stairwells and when you register where you live for administrative and postal purposes you give description at which floor and on which side the door is located.

The funny thing is that in Germany you have to pay TV license which is paid "per apartment". But since apartment doesn't have its own number, just street name, building number and freeform description then the authority responsible for collecting tv license fees doesn't know it a fee for this apartment is already being paid. So when you move in anywhere they always send you a letter so that you either start paying or provide TV license I'd number of a person living in this apartment who's already paying.

[inphus0rian]

apartments in france often (if not always) do not have unit numbers. i always thought it is to preserve anonymity.

[rootusrootus]

Would not the opposite be true? If you have to write your name out just so the mail can find you, you are less anonymous than if you just have a number that gets mail directly to your mailbox.

[jamwil]

You divulge your name yes but the upside is not having it correlated with a place. The name is written on the mailbox outside but is not mapped to a unit number on the envelope/parcel nor on the building.

The only way anyone can map your unit to your name is by physically watching you collect the mail then return to your unit.

[akira2501]

> This sounds like bad design by the property developer and a sloppy building authority.

This sounds like every day reality.

> Sloppy work, all around.

It's a system that explicitly relies on the cooperation of several independent entities. You were never going to achieve anything better than this.

[BobaFloutist]

Yeah wait how is it the BAN's fault that you don't have unit numbers, that's like complaining that you never receive your letters "just because" your house just fully doesn't have any street address and the post office needs to figure it out better without any involvement on your part.

[gabesullice]

Because datasets like the BAN exist to document how actual people and places are to be addressed. People and places don't exist to be addressed by the BAN.

[tomsmeding]

That sounds like chaos. Who thought constructing multiple apartment buildings without any kind of sensible post code or address was a good idea? Sure, this being reality BAN does not apparently meet reality, but it does sound like someone had the opportunity to keep reality sane here, and they didn't.

[gabesullice]

Agreed. This is a pretty typical case though, not a fluke. God bless the french postal workers. Don't invest in any drone delivery services here any time soon :P

[Ekaros]

In Finland in similar case, each stair well has own letter and each apartment has different number. So those are used always with the street house number.

Though the later case is bit messy with cross roads. As building can have two different addresses. Or same complex of multiple building have two different addresses for each building. With in my case one having A-C and other D-F stairwells... Oh, and numbers also are not restarted at least sometimes.

[stevekemp]

I live in Finland nowadays, and this system is nice.

I moved from Scotland where there are frequently buildings containing multiple apartments - tenements - there are there are two systems for the labeling of the apartments.

The first is the obvious one, "flat 1", "flat 2", "flat 3" (often this would be written after the number of the street - so flat six at number seven example road would be called 7/6 Example Road).

The second approach is the more physical layout. I used to live in "TFL, 7 Example Street". "TFL? Top flat - left side". You get "GFR" for "Ground-floor right", and similar examples. This worked really well if there were three floors to a building (top floor, middle floor, and ground floor) but the confusion got intensified if the building were higher.

There were times when you'd enter your postcode into an online service, ordering a home delivery for example, or setting up a new electricity contract, and you'd be presented with one/other of these systems. And broadly speaking it would always be the same. When I lived at TFL it was *never* called Flat 6, although I'd often enter it as 7/6 Example Street a time or two just to keep the posties on their toes!

To be honest most of the time the postal delivery people were smart, if I got mail addressed to "Steve, 7 Example Road" it would end up at the correct apartment. Either because the postal delivery person knew - they tended to have fixed routes - or one of my neighbours would do the decent thing and redelivery if it was sent to them in error.

[akira2501]

> but it does sound like someone had the opportunity to keep reality sane here

What is "sane" about reality? People want a place to live, they don't care about government databases.

[numpad0]

I think it means more towards that Uber Eats never works for that BAN than local post office have no clue and snail mail fails. GP didn't say the latter is the case.

[gabesullice]

You're right. Since the postal worker knows his route, he knows my name. So snail mail works perfectly well. Same for the Amazon delivery person (took a few visits). Same for the local pizza place.

It's online address suggestion/validation/one-time deliveries that don't work well. E.g. Uber Eats and DHL drivers always require a phone call so that I can guide them along the final hundred meters of their delivery. I usually go downstairs and meet them at the curb.

[tacostakohashi]

Frankly, that just sounds like a fire code / building code issue. Are these "apartment buildings" legal for habitation, with actual legal separate apartments, and not some weird subdivision/subletting situation?

In every place I have ever lived, having a clearly marked addresses and door numbers for apartments is required by the fire code. If there's an emergency that requires a fire or ambulance response, smoke in the air, etc, then "Nth floor, door on the right" is not a good thing to be explaining over the phone.

[gabesullice]

> Are these "apartment buildings" legal for habitation, with actual legal separate apartments, and not some weird subdivision/subletting situation?

Yes. In fact the 'résidence' (the conglomeration of apartment buildings) is considered one of the nicer, more desirable, places to live in the city. In the US, each apartment would be called a condominium [1], i.e., most are individually owned and not rented out.

[1]: https://en.wikipedia.org/wiki/Condominium

[playingalong]

In several countries in Western Europe there's hardly a tradition of apartment numbers in multi-apartment buildings. Instead the apartments are identified by family name of the owner. Or the main person living there. Or the person who used to live there some time ago. Or some guy backpacking in Asia and (illegally) subletting the apartment.

[Wizzah]

Belgium is a shitshow of governments (We have 7) but somehow one of these got to achieve a geolocated address register. Publicly available and they also have an API available to build your own application around.

https://www.vlaanderen.be/datavindplaats/catalogus/adressenr...

[saxomoose]

Am currently working on that at Digital Flanders. Curious about any use of the API out there.

[Wizzah]

I use it through the wonderful QGIS plugin for georeferecing .csv's.

I coördinate an 'igs lokaal woonbeleid' and this has proven to be tremendously useful. Maps are the best way to visualise the impact that we have and being able to pinpoint an exact location has prevented a lot of mistakes and misunderstandings. 10 Years ago it wasn't unthinkable that my colleagues lost several hours in a day searching for certain houses. I was one of the first that started using capakeys instead of adresses in my company.

[riquito]

On the bright side, you know about this and you could potentially suggest and follow any changes, which would be impossible without a single source of truth

[GJim]

> GPS coordinates

*coordinates

There are four GNSS constellations, of which GPS is only one...... a statement that negates the fact ones position on Earth may be calculated using a variety of other means.

EDIT: In response to replies below; One isn't questioning the coordinate system (!), rather the assumption as to how they have been calculated.

[arnsholt]

In this context, it's not terribly hard to divine that they probably mean EPSG:4326 coordinates. I was going to comment that one of the ETRS89 UTM zones might be easier to work with, but on second thought the data almost certainly includes the DOMs if not the TOMs, so a global coordinate system is probably best.

[manarth]

The BAN provide fields `long` and `lat` which are WGS84, and also `x` and `y` which are coordinates expressed in "the appropriate local CRS" (without much elaboration on what that would be).

[willyt]

That would be the French national grid system, no? The UK has the ordnance survey grid which is based on the OSGB36 datum. I'm pretty sure France will have a similar national datum to create their own local grid coordinates as planning and building works needs to be done in a more accurately aligned local datum than WGS84.

[wongarsu]

For mainland France it's reasonable to assume the French national grid. But what about French Guiana in South America or Mayotte in Southern Africa (an island north of Madagascar)?

France still spans the globe, with many places treated as equals to the French mainland.

[ryandrake]

Not to mention that “latitude” and “longitude” cannot uniquely describe an address, regardless of the datum or ellipsoid. Maybe that is not the intent of storing the coordinates. Lat/Lon says nothing about floor number in a multi-story apartment.

[defrost]

There are many ways to calculate an earth position, sure - to name a few; triangulation from stations, LORAN, or a combination of the two with a frequency change and some moving stations such as one of the five GNSS constellations.

There are many coordinate systems; these days in 2024 it is almost universal to calculate from various stations to a WGS84 position, in that coordinate system and using that geodetic datum.

Back in the day, there were many datums in common use, based on a plurity of reference ellipsoids, with a multitude of pojections in common use.

https://en.wikipedia.org/wiki/Earth_ellipsoid#Historical_Ear...

To this day there are several thousand indexed earth coordinate systems:

https://en.wikipedia.org/wiki/EPSG_Geodetic_Parameter_Datase...

https://epsg.org/home.html

[pjc50]

Like "Hoover", "GPS" is now a generic term for positioning systems.

[extraduder_ire]

For Positioning Systems that are Global, anyway.

[yard2010]

Fun fact: the word Νερό (nero) means water in greek. The actual meaning is fresh (I think it's the source of the word "new" too). It turns out, that many years ago you meant something else than fresh water by saying just water, so you have to be specific when you're talking about fresh water. In ancient greek water is ὕδωρ (hudr, think hydro, water) and fresh water is νεαρὸν ὕδωρ (neron hudr). Sometime in the past, the ancient Greeks were sick of saying 2 words to say water. So they dropped the second one.

Something similar happens with GPS coordinates. People are just saying GPS when they mean coordinates. even though the logical thing to do is drop the GPS (neron) and just say coordinates (hudr).

Personally, I think that language is just a bunch of symbols that have no real meaning. Each symbol means something only in a context, no matter how broad or specific. I would argue that it doesn't matter which word is more logical to use because logic is just a part of the context.

But you are right.

[ikr678]

Australia is similar, howeve, irrespective of how perfect your national addressing standards are, companies ingesting this data providing any sort of to-the-premise service still have to mash and clean and dissect it to fit whatever legacy system they are running.

I am aware of one utility provider that is locked into a custom network modelling solution that was officially sunset in 2014 and employs 3 ftes to manually create and delete addresses because the old address import tool broke.

[rtpg]

So many Australian sites use some data source that has an old name for the building I'm in, and sites are so convinced their address databases are right that I can't do anything about it! Mildly frustrating

[mabster]

Our previous apartment was listed under the wrong postcode. Annoying for Uber Eats because they would get lost.

Our current building is one of those 56-66 style buildings. Different service use a different number (e.g. postal is 56, gas is 58). We've had a few cases where our address doesn't match so the system rejects us. And when I vote I have to read which number they have upside down!

[ethbr1]

In the US, I had a family member's address change zip codes (approx similar to larger area postal codes) and associated city.

It took a surprising amount of time to cascade through systems, as in years.

I think we're at +8 years now, and Google Maps still has the old zip and city. Which means many websites do too.

[mormegil]

We have the same in the Czech Republic (Registry of territorial identification, addresses and real estate; https://cuzk.gov.cz/ruian/RUIAN.aspx (sorry, Czech only)). I would even expect it to be the case in more EU countries, cf. the INSPIRE directive.

[lukan]

Next step, automatically feed all the roads, speed limits, temporary blocks/construction sites automatically into OSM or similar accessible data.

[stef25]

Very cool. Nice effort by France.

For a while I played around with that kind of data here in Belgium, it's not easy to get it all standardized and "usable".

[nottorp]

Even in the far right US postcodes are public info :)

[crote]

The big difference is that US postcodes describe very large areas. A 5-digit US ZIP code describes a town or neighborhood, with on average 8200 people living in each ZIP code.

Most European postcodes are far more precise, often describing a single street, part of a street, or even part of a building. Postcode + house number is usually enough to uniquely identify a mailbox. For example, in The Netherlands on average only 40 people live in each postcode. That makes the dataset far more valuable for geolocation.

[dmurray]

The US also has 9-digit postcodes which usually map to a single building or smaller: aren't they public too?

[bluGill]

They are public, but the post office changes the last 4 digits every few months so there is no point in telling anyone what yours is. These days the post office can look up your street address and give you all the information they need - which is an 11 digit bar code good for the next week.

[aaronax]

Based on my personal experience, I really doubt that the last 4 digits of the ZIP+4 are changing more often than once per decade or longer. I could see the delivery point of the 11-digit code changing every few months, but you are already aware of that code system so it is not simple confusion between the two on your part.

Could you provide more information or a source?

[bluGill]

20 years ago they changed all the time. Wikipedia doesn't mention this though. These days the post office can read the street address via computers and get the 11 digit code they need, so I suspect they don't need them. (for PO boxes the 9 digit code apparently doesn't change)

[terribleperson]

My 9-digit zip hasn't changed in at least 10 years.

[sroussey]

Mine has not changed in 25 years.

[toomuchtodo]

Is there a a reason this hasn't been pushed for at the EU level?