[Tagging] Rethinking Map Features

Yuri Astrakhan yuriastrakhan at gmail.com
Sat Aug 3 22:06:32 UTC 2019

The biggest issue with using Lua/Server side scripting with large lists is
that every single data item used on a wiki page requires a separate SQL
query (or even multiple ones), due to how mediawiki + wikibase is
implemented.  On the other hand, relying on TagInfo has some shortcomings -
TagInfo does not (yet) understand data items, relying on its own wiki page
parser, it is very fixed in a way it can present information, and every
wiki page view also uses makes 1 or more external call to taginfo (higher
chance of something going down).

There is a popular middle ground that can solve it for us -- very flexible,
highly performant, uses a common data source (data items), and relies on a
single system.  Essentially it is a bot-updated wiki markup:

* an editor adds a special template at the top of a wiki page, where they
specify a SPARQL query for the data they want - i.e. "find all
label+description+image of data items, whose type is a 'tag' and whose key
is 'denomination'".  A bot would run that query on occasion (e.g. once a
day), and append query results to that same page after the template.  Thus,
the result becomes a regular wiki markup, without any significant server
costs.  See https://www.wikidata.org/wiki/Template:Wikidata_list

The PROs:
* The bot can run at any moment, by anyone, to update the data
* In the worst case of a bot completely dying, wiki markup could be edited
by hand until the bot is fixed
* very flexible - a complex query could get any data needed for the output,
and the output is templated to show in any kind of a list/table format.

* every list update is essentially a wiki page edit, slowly increasing
history. This is not that big of a deal because size wise the growth is
small and has very little performance impact, plus it makes it possible to
track changes with time.

On Sat, Aug 3, 2019 at 5:25 PM Andrew Hain <andrewhainosm at hotmail.co.uk>

> Now the wiki has data items and scripting in Lua I have been wondering
> whether they are a useful alternative to Taginfo-driven lists.
> Advantages of server scripts:
>    1. Descriptions can be generated from data items, tharefore they can
>    be in a language where there is no long form documentation for the key.
>    This resolves the issues that have limited use of taglists in languages
>    other than English because descriptions can be rolled out quickly and some
>    can be copied from the old map features templates.
>    2. Tables at the top of pages are visible immediately,
>    3. A successful connection to tagindo.openstreetmap.org is unnecessary.
> Advantages of taglists driven by Taginfo:
>    1. The technology aleady exists and can be rolled out.
>    2. Separate scripts avoid overloading the server (Map Features in
>    Polish, Ukrainian and Japanese hits wiki limits).
>    3. The web scripts are free-standing and can be hosted on another
>    website outside the wiki,
> (crossposted from
> https://wiki.openstreetmap.org/wiki/Talk:Taginfo/Taglists#Server_scripts_as_alternative_taglists
> )
> --
> Andrew
> Talk:Taginfo/Taglists - OpenStreetMap Wiki
> <https://wiki.openstreetmap.org/wiki/Talk:Taginfo/Taglists#Server_scripts_as_alternative_taglists>
> Languages. This is a very cool feature! One question: Could the template
> get the langugage automatically? I know this is done on some templates
> (e.g. Template:Tag).-- Jojo4u 17:20, 20 August 2015 (UTC) . I am not a
> template wizard.
> wiki.openstreetmap.org
> ------------------------------
> *From:* Joseph Eisenberg <joseph.eisenberg at gmail.com>
> *Sent:* 02 August 2019 14:22
> *To:* Tag discussion, strategy and related tools <
> tagging at openstreetmap.org>
> *Subject:* Re: [Tagging] Rethinking Map Features
> Andrew,
> I now think it is a good idea to switch to taglists for all of the Map
> Feature page templates. It will make it much easier to keep the pages
> consistent and to a reasonable length if all of the descriptions are
> pulled from the wiki pages directly (just as is done for descriptions
> used by Taginfo).
> This just means that any deprecated or discouraged tags which are
> currently "strikethrough" on Map Features will need something in the
> description that mentions that they are discouraged. This is a good
> idea anyway, so that the documentation is consistent.
> Joseph
> On 7/7/19, Andrew Hain <andrewhainosm at hotmail.co.uk> wrote:
> > I have been working on a scheme to improve the cross-language quality of
> Map
> > Features.
> > [
> https://wiki.openstreetmap.org/wiki/Talk:Map_Features#Reimagining_Map_Features
> ]
> >
> > Of course the page may deserve a bigger or deeper rethink.
> >
> > --
> > Andrew
> > Talk:Map Features - OpenStreetMap
> > Wiki<
> https://wiki.openstreetmap.org/wiki/Talk:Map_Features#Reimagining_Map_Features
> >
> > amenity=school rendering colour. amenity=school is displayed in the page
> as
> > a light-purple area for ways, whereas mapnik renders them as a pale
> yellow
> > colour
> > wiki.openstreetmap.org
> >
> >
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