[Tagging] was: on poi (was: building=disused)

Kevin Kenny kevin.b.kenny at gmail.com
Thu Jan 16 19:13:54 UTC 2020

On Thu, Jan 16, 2020 at 9:47 AM Paul Allen <pla16021 at gmail.com> wrote:
> Sometimes I use was: for that, more usually I put the info in a note.
> I tend to use was and disused on former chapels and churches that are
> of a style that are instantly recognizable as such.

I similarly leave it off a lot of buildings!  I live in a part of the
world where a lot of European settlement was done by stern Calvinists.
Their churches ('church' vs 'chapel' is an easier distinction in a lot
of northern Europe than it is here!), their schools, their town halls,
their social gathering places all pretty much looked alike - plain and
boxy, with little ornamentation.

This is a church: https://www.flickr.com/photos/gwp57/11201706423
This is a schoolhouse:
This is a social hall
This is a government building:

They're kind of hard to tell apart without a sign, and indeed, some of
these buildings served multiple purposes in their history. It's not
worth getting worked up over how they fit in some sort of Platonic
ontology where 'church', 'school', 'government', 'clubhouse' are
distinct building types. If I have to do historical research to decide
what to put in `building=*`, it's no longer 'mapping what a user will
see on the street.'

> There are a lot
> of chapels around here that are no longer in use for anything.  There are
> a lot of chapels around here that have been converted to other uses
> (mostly domestic residences).  I usually put building=chapel or
> building=church on them and was or disused on the amenity=
> place_of_worship.

'Church'/'chapel' seem to be the unique example that everyone resorts
to when identifying the former purpose of a building - because in so
many places or denominations, the architecture is distinctive. Most
other 'building=*' values are considerably less useful when the
building is repurposed.  In fact, in the corner cases, they serve only
to confuse. https://upload.wikimedia.org/wikipedia/commons/b/b0/Imam_Al-Khoei_Foundation_8989_Van_Wyck_jeh.jpg
is obviously a former factory, and equally obviously a current mosque.
It's surely not worth getting worked up over what to put in its

That said, by the same token,
https://eventective-media.azureedge.net/1936164_lg.jpg gets
'building=church' even though it's now a banquet hall. I'll give that
one "looks like a church." 'Church', though, seems to be quite a
special case.

> Better than was or disused for stuff that is no longer there is removed.  I did that for
> a couple of phone boxes outside a building for which there are many images scattered
> around the internet.  They're completely gone, no trace of them remains, please don't
> put them back because you saw them in an image.  There's no other way of warning
> an armchair mapper not to add them without mapping them with a removed prefix
> (or was, or disused, but they don't really mean removed).

Yes, indeed! 'Removed', 'demolished', and 'not' are all useful when
something that isn't there shows up in aerials or in widely-consulted
third-party sources, as a warning to the mapper that the situation on
the ground doesn't match the imagery or the database.

> By now we'll probably have woken up the strict interpretationalists who insist
> on following "rules."  "We don't map history" isn't a rule, it's a very simplified
> interpretation of "We don't map things that aren't there."  Which, itself, is a
> very simplified interpretation of "We don't map things that aren't there in a
> way that they get rendered, or clog up the database, or have other bad
> effects.  We only map things that aren't there if it's necessary to stop
> armchair mappers making invalid corrections."

Or we map remnants that _are_ there - I'm fine with mapping something
like `landuse=brownfield disused:amenity=prison` for a closed prison
complex that the state has been trying for years to sell to a
developer, or `highway=path railway=abandoned` (following the lead of
local rail mappers rather than the Wiki recommendation, because the
local mappers have a locally consistent tagging scheme), or
`tourism=attraction building=ruins ruins:building=hotel
historic=ruins` (and appropriate `heritage` tagging, because the ruins
are a recognized historic site

> OSM isn't (or shouldn't be) about blindly following a strict interpretation of
> supposed rules.  It is (or should be) about producing a map that is as
> useful as possible, and there are guidelines (that may look like rules) to
> help you do that.

Yes, again! Many of the rules like 'don't tag for the renderer' and
'don't map things that aren't there' come down to: don't tell lies so
that things render 'correctly'. There is almost always a tagging that
tells the truth (perhaps imprecisely) and renders as desired. Mapping
'things that used to be there' to warn mappers that they aren't there
- when there's strong but incorrect external evidence that they are or
were in the field -  is an entirely reasonable thing to do. Using
tagging that doesn't render for those things is also perfectly fine -
we don't want them cluttering the map.

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