[Talk-transit] NaPTAN bus stops

Roger Slevin roger at slevin.plus.com
Fri Aug 21 16:38:52 BST 2009


Peter

 

I can confirm that the Department for Transport would be supportive of any
way in which we (and the local editors who maintain NaPTAN data as best they
can) can get the feedback from OSM contributions to improve data accuracy.
I will be happy to discuss how best this can be done - but I suggest that
you and others on this list are much better placed to propose a method that
works within the framework of OSM.

 

Roger

 

From: talk-transit-bounces at openstreetmap.org
[mailto:talk-transit-bounces at openstreetmap.org] On Behalf Of Peter Miller
Sent: 21 August 2009 16:22
To: Public transport/transit/shared taxi related topics
Subject: Re: [Talk-transit] NaPTAN bus stops

 

 

On 21 Aug 2009, at 15:49, Chris Hill wrote:





I've started to survey the bus stops Thomas imported for Hull. I chose a 
small area to look at to see how it went. 

   * Out of 12 stops surveyed, 2 don't exist on the ground. 
   * The codes given as the naptan:AtcoCode are not displayed on the
     stops' signs, but an abbreviated version is, for example:
     naptan:AtcoCode=2290YHA01230 is displayed as 29901230.
   * The naptan:Bearing seems good using 8 cardinal points.
   * The positions are well placed against the road so far, but the
     position along the road can be quite inaccurate.  This cannot be
     random GPS inaccuracy as they would equally be away from the road
     but more likely some kind of human error.
   * The whole process will take a lot of work!

 

I have been making a start on the Suffolk data (Ipswich to be precise).

 

I think we will find the nature of the errors varies by county. I found the
following:

 

The two bus stations had all the right number of stops but they were poorly
aligned to the service roads so I adjusted their positions. We need to have
a discussion about how to code the stopping points for end-on bus stop bays
at some point, but lets leave that for a while.

 

One of the bus stations has bay letters (Bay A etc), the other uses public
service numbers, so the stop is known as (12 Stop) or (13/3 Stop) which
seems likely to go wrong when new services are introduced, but they are
correct as per what is written on the shelter.

 

The bus stops in one of the bus stations needed bearings added which I added
using the naptan field. Is that ok? or should we populate a standard
'bearing' field which we change and always leave the official naptan field
alone?

 

The new hospital mini bus station showed four new bus stops, but there are
only two. I removed the other two, possibly I should have marked them 'not
present'.

 

I found about 6 bus stops that were marked as 'customary' but which
certainly existed and were 'marked' - one even had a lay-by. I have added a
highway=bus_stop field and changed the NaPTAN field. About half the
customary stops existed for real, one almost certainly doesn't exist (it is
very near to a new bus stop), the rest were quite possibly real.

 

There is a common problem in Ipswich of muddling 'Adjacent' and 'Opposite',
so the stop marked 'Back Hamlet (adj)' is actually opposite and vice versa.
I have corrected a few of those, again, I have used the NaPTAN field which I
am not entirely happy about but where else should it go?

 

Some stops say that are adjacent to a road when the road has the same name
on both sides of the road so it isn't clear from the name if the side is
correct. This naming is not really very satisfactory but that is not our
problem for now - I will use the bearing as the main indicator of the side
of the road.

 

I have had to tweek the positions of some stops to get the on the correct
side of the road.

 

More to do, but I have not found it too time-consuming so far as there is no
need to go into all the side streets and the town is not that large. I will
just go into town by different routes each time for now and then think about
some longer trips. Possibly I am not doing the job very well!

 

I guess I have probably tweeked about 10% of them one way or another,
normally just fine tuning the position.

 

I have reported the faults I have found via the professional service we run
for the DfT for the purpose (http://www.itoworld.com/static/naptan). I
suggest that the DfT/Traveline might consider making this interface
available to OSM mapping people to do the same or opening up a public
version.

 

It will be useful in time to run a comparison between the current NaPTAN and
the current OSM and produce reports of where they are diverging. We would
need the permission of the department to take a cut of the NaPTAN data
before each run but I think they would be supportive.

 

 

 

Regards,

 

 

Peter

 

 


On the stops that are missing I will remove the highway=bus_stop tag and 
add physically_present=no as per the suggestions from the wiki page.

I have found 1 stop (so far) that is not as described.  The stop is 
described as on Gershwin Road, when it is actually on Sibelius Road 
(based on its code).  The bearing is N when the stop points W.  So how 
much of the Naptan data (if any) should I change?  I can move the stop 
to its actual position, but then the naptan:street will not match the 
street it is on and so on.  Any opinions, or suggestions are welcome.  
If we reach a consensus then I'll amend the wiki page.

Cheers, Chris

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