[Tagging] public_transport=platform rendering on osm-carto

osm.tagging at thorsten.engler.id.au osm.tagging at thorsten.engler.id.au
Wed Jun 20 17:53:56 UTC 2018

{Public transport platforms/stops represent a transition between two different types of movement. Usually foot on one side, and some form of vehicle on the other.


To fully map this, you need two nodes/ways/areas.


One, which is connected to the foot network. That is your public_transport=platform. In this regard, PTv2 is easier than the old scheme, as you no longer have two separate highway=platform and highway=bus_stop. You only have a single public_transport=platform. If it’s on a node, then it’s just a simple pole or otherwise marked stop without any real platform, if it’s tagged on a way (representing the platform edge) or an area (representing the whole platform) then you got an actual platform.


And one, which is connected to whatever network the vehicle runs on. rails, highways, waterways, whatever. That is your public_transport=stop_position. 


You CAN map both of these, but you NEED only one of them for a stop. That is clearly documented on the wiki:




“It is not necessary to map both the platform and the stop position. One of the two is enough. Mappers in some countries map both (e.g., Germany) while other countries primarily map platform nodes as the only objects containing all the stop's details…”


If you only map one of the two, then it’s better to map the platform instead of the stop_position, because the stop_position can usually be derived approximately by finding the closes point on the route to the platform node/way, but you can’t very well derive the position of the platform from the stop_position.



So, valid minimal tagging under PTv2 is very simple:


You have one node (if there is no clear platform) or a way (along the platform edge) or area (the whole platform), which is tagged as public_transport=platform (plus whatever mode of transport is served at the platform, so bus=yes or tram=yes, or …)


That’s it.


From: Jo <winfixit at gmail.com> 
Sent: Thursday, 21 June 2018 03:19
To: Tag discussion, strategy and related tools <tagging at openstreetmap.org>
Subject: Re: [Tagging] public_transport=platform rendering on osm-carto


If v2 of the 'new' scheme means that we have to create 2 objects for each and every bus stop and add both of those to the route relations and duplicate details across them, then v2 has failed.


We should have exactly 1 object that represents the bus stop. A node next to the way and only add that node to the route relations.


if there is an actual platform, we can draw a way or an area and tag it highway=platform/railway=platform. These should not be added to the route relations.


Neither should the stop_position nodes be added to the route relations, nor should they get details like name, ref, etc.


So 1 node to represent the bus or tram stops, next to the way on either side and only add details to those and only add these to the route relations.


These nodes can get the public_transport=platform tags.


if we can start doing it that way, we will get a way of mapping public transport that is easy to understand for everyone. If we don't the wiki will remain murky, unclear and ambiguous.


I rest my case.




Op wo 20 jun. 2018 om 18:53 schreef marc marc <marc_marc_irc at hotmail.com <mailto:marc_marc_irc at hotmail.com> >:

Le 20. 06. 18 à 17:44, Jo a écrit :
> Actually I have started to remove public_transport=platform from WAYS 
> with highway=platform and railway=platform. As far as I am concerned 
> public_transport=platform goes on NODES

sorry I didn't understand why (or maybe yes I prefer to not understand)
Zverik's propal that you clone to request that public_transport=platform 
as way should be downgraded to a node-only HAS FAILED !
So if another mapper extend the node to better match the geometry
of the plateform, why are you revert it ?
yes wiki is ambigous. but for almost (?) all objects the extend
from a node into a more precise geometry has always been considered
an improvement, not a mistkae that need to be fixed.
So the next contributor will probably add the PTv2 tags you deleted.

> Removing those tags from ways comes from the objection of some people 
> that there would be both a way and a platform with the 
> public_transport=platform tag.

I remember this talk about that on tranport (french-speaking transit) 
mailing when it became apparent that duplicate objects were so common
in France that they affected stats at a regional scale.
This resulted in a collective work to add missing PTv2 tags,
many contributors spent many hours for that and fix a lot of mistake.
Currently the region of french capital is nearly 100% PTv2 and at the 
country scale in france, there is almost no highway=plateform tag left 
that does not also have its PTv2 equivalent.

Of course one stop in one direction should have :
- only one plateform per "passenger waiting area" (including all variant 
public_transport=platform highway=platform and railway=platform)
- one stop_position

having one "passenger waiting area" mapped as a node + as a way + a MP 
like I already see, with tags randomly distributed or duplicated between 
these osm objects that represent the same thing, it is a mess....

and PTv1 tag should of course be put only on one of the same objets.
If not, you make duplicate objet for the same feature... like currently.

> In other words, the rendering of *=platform on WAYS is just fine as it is.

of course that it is the continuation of Zverik's failed proposal.
but check current pratice :
the supremacy of public_transport=platform over highway=platform
is even clearer if we take into account the duplicate tag
900k for public_transport=platform without (highway=platform or 
84k highway=platform + public_transport=platform
only 9k highway=platform without public_transport=platform
the community has already twice rejected this unintelligible wish to 
have a PTv2custom with different rules totally useless depending
on the transport mode.
PTv2 consists precisely in making things more HOMOGENEOUS.
So please reconsider your modifications and take into account that 
highway=plateform and public_tramsport=plateform are 2 tags for the same 
concept (a passenger waiting area for a public transport), even if the 
render support only the oldest and less common schema for *=platform

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