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

Stephen Sprunk stephen at sprunk.org
Mon May 6 18:53:10 UTC 2019


On 2019-05-03 12:09, Dave F via Talk-transit wrote:
> On 30/04/2019 18:34, Stephen Sprunk wrote:
>> 
>> A platform is where people wait to board; if they stand at a pole 
>> (typical for buses), then the pole is logically the platform.
> 
> 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.  It's 
pretty well established that using a platform node for a mere pole is 
valid.  People wait there to be picked up, regardless of the actual 
surface type (which can change over time anyway).

> 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.

Ditto for railway=platform implying public_transport=platform, 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.

>> 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.  Same as any 
other structure where someone puts a node as a "temporary" marker.  It's 
better than nothing, but it can be improved.

>> If you're trying to construct a route that involves walking to a bus 
>> stop, riding the bus to another stop, and then walking some more, then 
>> you need a linkage connecting the bus route (using stop positions) 
>> with the walkways (using platforms).  I'm not saying that's the only 
>> way to do it, but it's the only way that was proposed.
> 
> Do you have an example as I'm unsure what you mean by 'walkways' and
> platforms are disconnected from the bus routes, as are bus stops, so,
> as I said above, PT can use bus stops.

Walkways as in places where people walk.  The router needs to give me 
directions down the sidewalk or whatever to where I wait for the bus.  
If the only node is on the highway, am I supposed to stand in the middle 
of the highway until I get hit by the bus?  No, it should route me to 
the platform beside the highway.

But the bus stays on the way, so it can't stop at a platform correctly 
off the way.  That's where the stop position comes in, and the supposed 
need to link the two together.

> Markus previously said "OsmAnd Is able to navigate with routes
> consisting only of highway=bus_stop beside the road."

I assuming they're calculating the stop position based on geometry, 
which  should work fine in most cases.  But if an explicit stop position 
does exist, they should use that instead.

> 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.

S

-- 
Stephen Sprunk      "Those people who think they know everything
CCIE #3723         are a great annoyance to those of us who do."
K5SSS                                             --Isaac Asimov



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