[Tagging] start_date variants

Sat Feb 16 21:01:47 UTC 2019

I'm a bit confused by this thread, somehow I have the impression I missed
something (that's why I left TOFU in this mail).

Anyway, I'd like to summarize:

There are many-many objects (most of them buildings - 96%) tagged with
start_date=* - I think, that's great. start_date is quite well documented
and very flexible concerning ranges and approximations.

My suggestion was to use a prefix "building:" if the start_date of the
building differs from the start_date of the amenity. It is not very common
though right now, with only 163 uses. Only 9 have both start_date and
building:start_date.

When investigating this issue - triggered by this thread, I/we discovered
that there are alternative building age tagging schemes.

I made a search through taginfo and found some more tags:

* "building:age" - very popular (132071), but rather useless. 41% have the
  value "post_2000", 19% "pre_2000". 12.9% "10_to_30" (should this mean "
  10 to 30 years? - this is wrong on so many levels, I don't even know where to
  start).
  It's documented on the start_date page as possible tagging mistake.
  https://taginfo.openstreetmap.org/keys/building%3Aage#values
* "building:year_built" - some (3005). Mostly start year or in some cases
  approximations (but different syntax from start_date).
  I found no documentation at all.
  https://taginfo.openstreetmap.org/keys/building%3Ayear_built#values
* "building:buildyear" - some (2051). Only very few objects use
  approxiations.
  As mentioned by Sergio, it was introduced in the IndoorOSM proposal.
  https://taginfo.openstreetmap.org/keys/building%3Abuildyear#values
* "year_built" - some (2417, whereas many might not be buildings).
  No documentation.
  https://taginfo.openstreetmap.org/keys/year_built#values
* "building:year" - few (102).
  It's documented on the start_date page as possible tagging mistake.
  https://taginfo.openstreetmap.org/keys/building:year#values

It seems, that 'start_date' is be the preferred way to tag the age of a
building. Tag is popular and well documented.
I took the liberty of adding it to the additional attribute section on
https://wiki.openstreetmap.org/wiki/Key:building

What I wanted, was to introduce a way to highlight different start_dates
for the same object (e.g. old building, new use). I personally
would prefer 'building:start_date' as fallback, as it uses the same syntax
as start_date. And it could be applied to other keys as well (and this is
being used).

Do you think, that any of the other tags should be supported as well?

Anyway, I will modify the OpenStreetBrowser category to also supprt
"building:year_built", "building:buildyear", "yearbuilt" and
"building:year" (but with the syntax of the start_date tag). "building:age"
will be shown red (date format not supported).

I'm planning to introduce some quality assurance tools in OpenStreetBrowser
in the near future. I would show these alternative tagging schemes as
warnings.

greetings,
	Stephan

On Sat, Feb 16, 2019 at 04:08:03PM +0000, St Niklaas wrote:
> Hi Stephan & all,
> 
> I realised this see the lines below,
> 
> Sergio Manzi <smz at smz.it>
> Za 16-2-2019 16:06
> 
> Hello!
> 
> 
> Actually the analysis was not mine, but just the result of a query in taginfo (https://taginfo.openstreetmap.org/keys/?key=building%3Astart_date), but I guess I understand what's going on here:
> 
> 
> all of the objects you're referring are tagged with a start_date=* key, while the tag I was referring to (and was discussed in the mailing list) is building:start_date=* (note the presence of the "building:" namespace prefix...).
> 
> 
> A query for "your" key (https://taginfo.openstreetmap.org/keys/?key=start_date) returns 14246906 objects!!
> 
> 
> I don't know how many of those more than 14 millions objects are buildings, but I suspect quite a good number (an appropriate query in overpass turbo can clarify that, I guess).
> 
> 
> Normally I'm all in for supporting namespaces, but I understand that we have a problem here and it would be just silly to throw away such a bunch of good information.
> 
> 
> I suggest you to answer to the mailing list too and underline this situation. You can quote my answer in full or in part, if you wish.
> 
> 
> Regards and my compliments for your outstanding contribution,
> 
> 
> Sergio
> 
> 
> 
> 
> On 2019-02-16 15:42, St Niklaas wrote:
> 
> Hi Sergio,
> 
> 
> I doubt your analyses, since almost all buildings (5 million) in the Netherlands that have been imported since 2014, carry  "start_date = 2022" or alike. Have a look here https://www.openstreetmap.org/#map=19/52.53890/4.83687
> 
> The import comes straight out of the Dutch Cadastre after a lot of hard work getting the go ahead from the government. But my contributions are not among them, the BAG (Basis Addresses and Buildings) don’t measure covered buildings even if they are historic monuments, so that’s my speciality and they import my OSM work into the BAG 🙂
> 
> 
> Greetz
> 
> 
> [https://www.openstreetmap.org/assets/osm_logo_256-cde84d7490f0863c7a0b0d0a420834ebd467c1214318167d0f9a39f25a44d6bd.png]<https://www.openstreetmap.org/#map=19/52.53890/4.83687>
> 
> OpenStreetMap<https://www.openstreetmap.org/#map=19/52.53890/4.83687>
> OpenStreetMap is the free wiki world map. OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
> www.openstreetmap.org<http://www.openstreetmap.org>
> 
> 
> 
> ________________________________
> 

-- 
Seid unbequem, seid Sand, nicht Öl im Getriebe der Welt! - Günther Eich
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