[Talk-it-southtyrol] Import numeri civici in OSM dal DB della Provincia di Bolzano

[Martin Raifer]

I'm answering in English, if you don't mind.

I guess you already know it, but just in case: Please make sure to read  
and respect OSM's Import Guidelines [1].

As you have already done some work, it would now make sense to create a  
wiki-page for the import. I made one for the previous opengisdata.eu/TOL  
house-numbers import attempt here: [2]. You can either extend that page or  
(probably better) create a new one to make it clear that this is a new  
attempt.

-- Import Schedule --

I like the idea of a „pilot town“. It doesn't really matter which one  
exactly, but it probably should cover all the corner cases we have to  
consider, which probably don't exist all in one single place. So, I'd  
propose to have a few pilot towns, for example one larger town with  
pre-existing house-numbers, one smallish municipality which doesn't use  
street names for addressing (like Martell or Rodeneck, but those are  
already well mapped) and one Ladin town.

Can you explain what your flow-chart[3] actually means? I don't get it.  
What does the „Community sais YES/NO“ mean? Is this comparable to how  
OSMLY[4] does imports?

-- Tagging --

Addressing in OSM isn't always very straight-forward (especially not in a  
multilingual region), so here are my ideas:

Relation-based addresses are preferred by some mappers (even I mapped my  
first few house-numbers that way), but it has also it's downsides (harder  
to comprehend by new mappers, less support in OSM software, …) and it  
would certainly complicate the import. Other address imports (like the one  
in Denmark [5]) also only used simple nodes.

* addr:country
Can be omitted, but doesn't harm to include either.
* addr:city
Could in principle also be omitted, but again, it doesn't harm to have it  
and in some corner cases it could even be necessary to have it (like a  
house very close to an administrative border).
* addr:postcode
I would include it, because postcodes actually can be different within  
Municipalities in South Tyrol (e.g. Eppan has 39057 and 39050) and the  
borders of postcode areas may not be the very same as administrative  
boundaries.
* addr:place
I think you are misinterpreting this tag. It is not used to set the  
"frazione" of an address like "St.Pauls" in "Schulweg 1, St. Pauls, Eppan,  
39050". For this there is addr:hamlet (see below). addr:place is used in  
the following case: A small village has only a few unnamed roads and all  
addresses are based on the locality: "Gand 45, Martell, 39020". Here  
"Gand" is not a street-name, but a hamlet. In such cases, we use  
addr:place _instead_ of addr:street. See an example [6].
* addr:hamlet
If an address is street-based, one can also provide the "frazione" of the  
respective house by using this tag. As far as I know it is not required  
for physical mailing, but it would be nice to have this information, if  
available, to make searching more accurate (e.g. a user may only search  
for "Schulweg 1, St. Pauls" instead of "Schulweg 1, Eppan").
* addr:street
See above
* addr:housenumber
Surely needed
* addr:full
I would not import this field, as this is only intended to be used  
_instead_ of all the fields mentioned above. As described in the wiki:  
“Use this for a full-text, often multi-line, address if you find the  
structured address fields unsuitable for denoting the address of this  
particular location. Examples: "Fifth house on the left after the village  
oak, Smalltown, Smallcountry"”

-- Multilingual Tagging --

When it comes to multilingualism it gets a little bit complicated:

In order to get OSM's search tool to work, the name of the street (or  
locality) must exactly match the value in addr:street (or addr:place).  
While we have a naming convention in OSM (namely multiple names in the  
name-tag separated by a dash with the locally dominant language first), it  
is not (yet?) used everywhere.

As far as I know, it is possible to provide additional addr:street:de and  
addr:street:it fields. With such tags the search could even work if the  
street is not yet properly tagged. Same applies for addr:place:*,  
addr:hamlet:* and addr:city:*. And also for Ladin names with the postfix  
":lld".

So, I'd propose to simply use OSM's naming conventions and additionally  
provide the individual language versions for further clarity and a  
fall-back mechanism to get proper search also with incomplete OSM data.

When it comes to Meran, not even the city itself seems to know whether to  
prefer German or Italian, see this street [8] with exactly opposite  
language order on opposite sides of the street :D . In this case I would  
stick to the order most streets are already mapped, that is "German -  
Italian". I'd say that the decisive factor would be the mostly German  
speaking population in the vicinity (“metropolitan area”) of Meran.

-- Conflation --

This probably also needs a little extra attention.

If the house-number is already in OSM, I would keep the original geometry  
for good practice. Except of course, when OSM is incorrect (e.g. if the  
position is far off, or a house with multiple numbers has only one in OSM  
like in your example, etc.). In that case it would be OK to delete the  
data and insert more precise addresses instead.

And maybe with the following additional exception: If an address is  
already in OSM, but only as an additional datum of a POI (like a bar,  
shop, etc.) it would probably make sense to import an additional address.  
This is because the POI can relocate or disappear quite quickly, while the  
actual address usually doesn't.


That's it from me – for now ;)
Martin


[1] https://wiki.openstreetmap.org/wiki/Import/Guidelines
[2]  
https://wiki.openstreetmap.org/wiki/AltoAdige_-_Südtirol/OpenGISData_House_Number_Import#Conflation
[3] http://freegis.r3-gis.com/download/aa2osm/diagramma_osm.pdf
[4] https://wiki.openstreetmap.org/wiki/OSMLY
[5] https://wiki.openstreetmap.org/wiki/Import/Catalogue/KMS
[6] http://www.openstreetmap.org/browse/way/210598774
[7] https://wiki.openstreetmap.org/wiki/Nominatim
[8] http://goo.gl/AQw72X