[Talk-transit] Ideas for a simplified public transportation scheme

Dave F davefoxfac63 at btinternet.com
Tue May 7 13:29:46 UTC 2019

On 06/05/2019 19:53, Stephen Sprunk wrote:
> On 2019-05-03 12:09, Dave F via Talk-transit wrote:
>> This reinforces my point about misappropriation of tags. A platform is
>> a physical construction higher than the surrounding ground to allow
>> easier boarding.
> It's a logical platform whether it physically exists or not.

<smiles> A 'logical platform'?

 From OSM's main welcome page:
"OpenStreetMap is a place for mapping things that are both /real and 

"What it /doesn't/ include is... hypothetical features,"

>   It's pretty well established that using a platform node for a mere 
> pole is valid.

But you're mapping them as areas.
As bus stop tags are by far the more established, why not use that to 
map a."mere pole".

 From the bus stop wiki page:
"A bus stop is a place where passengers can board or alight from a bus."
Which is what you're claiming platform areas are. As I said it's pure 

>   People wait there to be picked up, regardless of the actual surface 
> type (which can change over time anyway).

Unsure why you believe surface is relevant, but as I said, your examples 
of platforms are imaginary, inaccurate & arbitrary.

>> A platform:
>> https://s0.geograph.org.uk/geophotos/04/76/30/4763016_2416f5ee.jpg
>> Not a platform:
>> https://i.pinimg.com/originals/38/90/a0/3890a0f451e1a6900d174b29125b3c80.jpg 
>> If (& I believe it's a big if), a separate tag is required to as you &
>> Markus suggest, one with a unique, non-confusing value should be used.
>> Many public_transport=platform are tagged on the same node as
>> highway=bus_stop. They have no raised construction Therefore they're
>> redundant - routing can use the bus stop tag for the "stop node beside
>> the
>> road" as Markus described it.:
>> https://www.openstreetmap.org/node/469760546#map=19/51.51026/-0.18630
> I'd be fine with saying that highway=bus_stop implies 
> public_transport=platform, except that some mappers put bus stops on 
> the way instead of beside the way and argue with anyone who tries to 
> fix them, so in those areas, separate nodes for the platform had to be 
> added.

 From the bus stop wiki page:
"The highway=bus_stop tag is widely used on a node off *to one side of 
the highway way* to identify the position where passengers wait for a 
bus beside the carriageway."

However, is it essential that highway=bus_stop is/isn't on a way? 
Routers should be able to adapt to both scenarios.

> Ditto for railway=platform implying public_transport=platform

railway=platform implies no such thing. It represents a physical object, 
nothing more, nothing less.

 From what I've seen public_transport=platform was conceived as purely a 
duplicating tag to 'collect things together'. I've yet to see a router 
that requires more than a stop position. Don't most just use 

 From what I've observed the PT schema went into too much detail which 
will never be used.

> , and it doesn't seem to have the same problem.  I'm not sure for 
> other modes since I've never dealt with them.
> If we could all agree on this, we'd just need to change the 
> documentation--and go fix thousands of bus stops that are in the wrong 
> place.

Great! That's much simpler than adding tens (hundreds?) of thousands of 
duplicating multi-noded polygons.

>>> That's easily distinguished from large platforms because it's a node 
>>> rather than a way/area.
>> Not really. To save time, contributors occasionally combine tags onto
>> a single object: litter_bins, shelters, benches *&* raised platforms
>> in the case of bus stops. I'm not saying it's the correct/best way to
>> map, but it happens.
> It doesn't make a difference for routing.
> If a platform is large enough that it matters for rendering, then 
> someone needs to go back and draw the platform as an area.

If it's a physical object, then yes.

>   Same as any other structure 

But your examples aren't structures. They're imaginary.

>> So, to be absolutely sure we're singing from the same hymn sheet, are
>> we agreed that 'public_transport=platform' tag to represent a place
>> where vehicles stop to allow passengers to alight, is redundant in PT
>> as another, existing, more prevalent tag - 'highway=bus_stop' can be
>> used instead?
> Notice what you did there: the platform tag "represent[s] a place 
> where vehicles stop".  That's the entire argument over bus stops in a 
> nutshell, which led to the redundant tagging.

I refer you back to the bus stop wiki page.
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