[Tagging] Still RFC — Drop stop positions and platforms

"Christian Müller" cmue81 at gmx.de
Thu Mar 29 14:54:13 UTC 2018


> Sent: Wed, 28 Mar 2018 22:20:21 +0200 
> From: "Michael Reichert" <osm-ml at michreichert.de>
> To: tagging at openstreetmap.org
> Subject: Re: [Tagging] Still RFC — Drop stop positions and platforms
>
> - If someone writes such a complicated proposal, he should ask the
> authors of map styles (if he isn't someone himself) for their opinion on
> the new tags. public_transport=stop_position/platform isn't easy to
> render without taking highway=bus_stop into account because (1)
> platforms do not have to be tagged with bus/tram/train/subway=yes and
> because you do not have to map both the platform and the stop. If you
> render only stop positions or only platforms, you will miss features in
> some areas. If you render both, you will have duplicated map icons.

You argue that we do have a platform or a stop_position or both in
any case  and  that a single map object is to be rendered ultimately.

The latter is an abstraction (specific rendering) of an abstraction
(data in the db complying to some model) of the situation on ground.

However, on high zoom scales, it does make sense to render both,
the stop_position and the platform, if both exist.  Lower zoom
scales should merge both in an icon, maybe.

I agree that rendering is difficult to some extent, if the data
is detailed, but it reflects the situation on ground adequately.
With less detail in the data, it is also less useful.  Rendered
maps are an important, but not the only use of OSM data.

bus/tram/train/subway=yes  are  _not_ optional for a specific
platform, these tags are mandatory in accordance to the modes
served by a _specific_ platform.  The reason this tag is set
optional is because not all modes apply to _all_ platforms all
the time.  Maybe documentation of this needs improvement.

However, even if the mode of the platform or stop_position is
not tagged, a generic PT symbol can be an appropiate rendering.


If I understand you correctly, it is hard to relate a stop_position
to a platform if they do not happen to reside in an osm relation at
the same time.  You need to do distance calculations ('around') in
this case, just to decide on low zoom scales  to not draw an icon
twice!?  This _is_ a rendering problem indeed, but it's not specific
to PTv2 (platforms and bus_stop nodes have existed before).


Greetings
cmuelle8



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