[Talk-transit] [Talk-gb-westmidlands] Naptan alignment

Joe Hughes joe at headwayblog.com
Tue Mar 31 22:54:36 BST 2009


FWIW, the stop locations given in GTFS data sets are also defined to
be the "location where passengers board or disembark from a transit
vehicle".

Cheers,
Joe

On Tue, Mar 31, 2009 at 2:15 PM, Roger Slevin <roger at slevin.plus.com> wrote:
> Peter
>
> I think it is important to separate out the infrastructure of shelters from
> the function of the bus stop - the shelter is often located where it can be
> fitted in ... and it can be mapped as a physical object.  A bus stop
> represents a function - the boarding or alighting of passengers.  It may be
> indicated in the physical world by a "pole in the ground" - which might be
> close to the roadside, or might be at the back of the footway.  In my view
> the "stop" that NaPTAN records represent is the point at which passengers
> board or alight ... either the point marked by the pole in the ground if it
> is close to the roadside, or a similar point which might be indicated by a
> post displaced from the roadside (or it might simply be a point which is not
> marked - but is clearly recognised by custom and practice.  If there is a
> lay-by, then this is a widening of the road carriageway - the bus stop
> location should still be close to the edge of the footway at the back of the
> lay-by.  Taking your three (?) possibilities, I think all this means that it
> is what you labelled "4".
>
> By the way - for those importing data for Birmingham, there was mention
> earlier this evening of "the marker for stops in Birmingham" in the context
> of stops that might be missing.  I am unclear what this marker is - as
> NaPTAN does not contain a marker for Birmingham, per se.  I can think of
> ways this might have been determined using the NPTG locality association  -
> is that what has been done?  If so the missing stops may simply be in a
> child locality which hasn't been correctly associated with Birmingham as the
> parent locality.
>
> Best wishes
>
> Roger
>
> -----Original Message-----
> From: talk-transit-bounces at openstreetmap.org
> [mailto:talk-transit-bounces at openstreetmap.org] On Behalf Of Peter Miller
> Sent: 31 March 2009 20:51
> To: Andy Robinson (blackadder-lists)
> Cc: talk-transit at openstreetmap.org; Talk-gb-westmidlands at openstreetmap.org;
> 'Brian Prangle'
> Subject: Re: [Talk-transit] [Talk-gb-westmidlands] Naptan alignment
>
>
> On 31 Mar 2009, at 20:22, Andy Robinson (blackadder-lists) wrote:
>
>> Peter Miller [mailto:petermiller63 at googlemail.com] On Behalf Of Peter
>> Miller wrote:
>>>
>>> 4) I notice that sometimes the NaPTAN stop and the OSM one are some
>>> significant distance apart which begs the question about which one is
>>> right.
>>
>> I've noted this too. I'm going to do a precise check in my area to
>> see what
>> accuracy I place on the NaPTAN positions. I've also from today
>> started to be
>> more precise about getting the position of bus stops when I survey.
>> I should
>> be within 0.5m +/- the GPS accuracy (generally sub 5m with this
>> Legend HCx I
>> use).
>
> If you are getting that precise it will be useful to agree where the
> stop should be. We might have a number of points
>
> 1) A pole and/or a shelter
> 3) Optionally a lay-by where the vehicle stops
> 4) A spot where one would expect to stand to get onto the bus
> (opposite the door).
>
> Can I suggest that it might be appropriate to use the position of the
> pole and/or shelter as the reference for the bus stop and applications
> should then assume that the bus stops at the road edge with its doors
> at the nearest point to the shelter. If that is not the case then
> possibly we need a 'stopping point' node next to the road to show
> where the front doors of the vehicle would be.
>
> Should we also create a 'lay_by' or 'bay' attribute to say if there is
> a place for the vehicle to pull in to pick up passenger. It might be
> neat to be able to describe what sort of facility is provided. In some
> places it will be a pull-in pull-out bay, in others it might be a pull
> up, reverse out bay. If we have that information then future rendering
> engines will be able to get it right.
>
> This is what I mean by pull-in pull-out
> http://www.palmengineering.com/images/busBay4.jpg
>
> And this is a Pull-in reverse-out one
> http://www.broward.org/bct/images/browardcentralterminal.gif
>
>
>
>
> Regards,
>
>
>
> Peter
>
>
>>
>>
>> Cheers
>>
>> Andy
>>
>>>
>>>
>>> Anyway, it looks like the detective work is now starts! Great work.
>>>
>>>
>>>
>>> Regards,
>>>
>>>
>>>
>>>> Cheers
>>>>
>>>> Andy
>>>>
>>>>> -----Original Message-----
>>>>> From: talk-gb-westmidlands-bounces at openstreetmap.org [mailto:talk-gb-
>>>>> westmidlands-bounces at openstreetmap.org] On Behalf Of Brian Prangle
>>>>> Sent: 31 March 2009 9:46 AM
>>>>> To: Talk-gb-westmidlands at openstreetmap.org; talk-
>>> transit at openstreetmap.org
>>>>> ;
>>>>> Thomas Wood
>>>>> Subject: [Talk-gb-westmidlands] Naptan alignment
>>>>>
>>>>> Thomas
>>>>>
>>>>> I've also looked at Google maps and their alignment is off too in
>>>>> exactly
>>>>> the same way ours is in areas I know well and have surveyed, so I
>>>>> guess
>>>>> it's down to the NaPTAN data. There are examples where I know the
>>>>> bus stops
>>>>> are in a row along the street (Corporation Street  and Acocks Green
>>>>> Village
>>>>> for example) but NapTAN has one or two skewed from the line by
>>>>> several
>>>>> metres.  Currently I favour correcting the NapTAN data  to what we
>>>>> know on
>>>>> the ground, but until a consensus emerges I'm laying off the urge
>>>>> to
>>>>> correct it.
>>>>>
>>>>> Regards
>>>>>
>>>>> Brian
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>> Talk-transit at openstreetmap.org
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>>
>>
>
>
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