[Tagging] Documentation issues of PT tagging schemes

[Leo Gaspard]

On 07/24/2018 11:17 PM, Jo wrote:
> The whole point of wanting to move to a simpler tagging scheme is to become
> able to write simple to understand documentation.

>From what I understood (so, second-hand information) PTv2 can be used
with as few objects and tags as PTv1, so it's not inherently more
complex. However, it allows more things to be tagged. Putting these
“more things” in small font at the end of the wiki page would be enough
to have a simple, yet complete documentation, and leave people who like
PTv2 the ability to tag complex things :)

> Dropping the "v1" tags that some like to call 'deprecated' is not possible,
> because then your stops don't render.

Honestly… proposal, mass-edit, renderers (that will have had a say in
the discussion, obviously, but I don't think they wouldn't welcome a
reduction of the number of tagging schemes) will be forced to adapt, done.

There seems to be strong resistance in OSM against re-tagging and
mass-edits, but in this special case, so long as it can be done in a
loss-less way, I couldn't understand how all data consumers and all
mappers (interested in having newcomers understand the documentation)
wouldn't agree.

So long as there will be 2+ tagging schemes in operation it'll not be
possible to have a simple documentation, and things will be a mess.

> Replacing highway=bus_stop by public_transport=platform doesn't work
> either, as you lose the information about the mode of transport,
> bus=yes/tram=yes.

https://wiki.openstreetmap.org/wiki/Public_transport seems to mention
that `highway=bus_stop` could be relatively well replaced by
`public_transport=platform, highway=bus_stop` (so just adding
`public_transport=platform`? Then again I don't understand what is PTv1
and what is PTv2 and what is a mix of “people actually do that” in this
page).

I personally don't care if “PT” is not exactly PTv2 but a mix of PTv1
and PTv2. All I care about is having clear guidelines, and I've been
told PTv2 is basically more featureful than PTv1 but still allowing
simple mapping, so PTv2 looks like the thing to use to me.

Then, once this “PT” tagging scheme would have been documented,
incremental improvements could be proposed to it, like having `bus=yes`
/ `tram=yes` tags on platforms or whatever.

All I'm saying is that *before* changing the way we tag, we should first
document clearly what people currently do and make the Grand Public
Transport Unification happen.

> Dropping the public_transport tags on stops seems somewhat more
> straightforward, but isn't completely either. (For example, I don't like
> stop_position nodes and won't add them everywhere, but I had started to add
> them where the itineraries terminate).

Maybe in my list I inverted stop_position and platform, I don't know.
But such a “simplify the documentation” effort would have to decide
which one is important and which one is not, and then make it explicit
so that everyone can tag just the important one and forget the
non-important one if they don't feel like it.

> We're stuck.

Until there is a clearly documented reasonably usable **unambiguous**
tagging scheme, then I agree with you, unfortunately. And a mass edit
would likely help for tools to be able to become *much* simpler by
handling only one tagging scheme and not trying to support 2,5 tagging
schemes :)