[OSM-talk] Re : Tagging Governance

Pierre Béland pierzenh at yahoo.fr
Tue Sep 10 07:55:39 UTC 2019

Hi Roland
It would help To better see the structure of
1.main tags2.attributes adding detailed infos To these tags
Also cases like polygons that should not be overlapped when related   To landcoverie. Amenity=university vs landuse=retail

Envoyé à partir de Yahoo Courriel sur Android 
  Le mar., sept. 10 2019 à 6:54 AM, Roland Olbricht<roland.olbricht at gmx.de> a écrit :   Hi all,

I have got into the duty to talk about tagging governance on the SotM
and I would like to develop that opportunity towards something that is
rather helpful in the long term.
To ensure that I am on the right track and not unintentionally after a
personal agenda I would like to ask you to comment on the findings so
far listed below.

To encourage a widespread discussion, I have spread this message on
German and French lists as well (these two because I understand the
languages) and will do so in addition on the tagging list. Feel free to
spread this message further as long as you remember to channel back all

Imperfect Flow of Information

Although many parts of the OpenStreetMap project are well translated,
the tagging documentation has substantial deficiencies. Over a random
sample of 10 tags the number of declared languages varies between 2 and
18, but only few are complete and up to date (sample: 2 of 10 for
German, 3 of 10 for French).

Another kind of imperfect information flow is that tag definitions can
be changed on the wiki page long after the tag is in widespread use.

The converse case that a tag is introduced without any documentation is
also happening. While this happens by ordinary users usually slow enough
to make sense of the added data, an import or organized edit might be
able to substantially skew the de facto meaning of a tag, regardless
whether it is in widespread use, documented, both, or none.

More Structure needed

The translation issues have been conflated with a different problem:
Different features may look very different between regions. E.g.
highway=primary and highway=unclassfied versus highway=track
need different sets of examples in Germany and the urban US on the one
hand and Iceland or rural Africa on the other. It is easy to mix this
with the translation into the predominant language in the area,
but the tagging challenges in Belgium, Canada, and Niger are
substantially different, although all three countries happen to have
French as official language. Conversely, there is no sane reason to
change tagging rules every block of houses in Brussels.

Additionally, people often have different search terms than the British
English tag names or their translations, and the wiki search engine is
infamous for its bad performance. Having explicit keywords to direct the
attention of a mapper to the list of possibly fitting tags might help.

A substantial problem source of the concept of proposals is
that it interacts with lots of tags in a nontrivial way and is
practically never properly applied to all affected tag definitions.
A proposal currently is an extra page although it should have much more
an impact like a Git commit, grouping changes across various tag
definition pages in a single changeset.

Legitimacy and Governance

What legitimation has a process if only a handful of people have that
have the time to write mails on a mailing list and to write wiki pages
are involved? In particular, if the proposals end up as being full of
contradictions or vague terms and leave necessary answers undefined.
Yet these still are the people that have shown the necessary long-term
endurance to assure maintenance and that do the work. Thus every change
to replace processes with better processes must be geared towards
broadening not narrowing the base of long-term maintainers.

Conversely, I fully understand mappers that are wary of sudden changes
in the rendering or the access to tags in edting software. A lot of
people whould probably appreciate to better understand what happens on
the way from a tag discussion to a final change in the renderer or
editing software. These processes are not secret, but often

Again, the various discussion channels and the lacking information flow
between them contribute to the bad mood. Even worse, the ratio between
people and channels means that evil or just plainly incompetent people
could easily take over some channels and contribute substantially to the
confusion. Good ideas how to redirect people and close down some of the
channels (e.g. wiki discussion pages) might be worth pursuing. On top of
that the wiki history is so much less helpful than what developers are
nowadays used to from version control systems that borrowing methaphors
and paradigms from there to the tag documentation is worth consideration.

This hopefully helps to foster that the authors of the documentation and
the mappers using a tag actually agree on its meaning.

Best regards,


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