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 <[email protected]> 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: [email protected] > [mailto:[email protected]] On Behalf Of Peter Miller > Sent: 31 March 2009 20:51 > To: Andy Robinson (blackadder-lists) > Cc: [email protected]; [email protected]; > '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:[email protected]] 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: [email protected] [mailto:talk-gb- >>>>> [email protected]] On Behalf Of Brian Prangle >>>>> Sent: 31 March 2009 9:46 AM >>>>> To: [email protected]; talk- >>> [email protected] >>>>> ; >>>>> 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 >>>> >>>> >>>> >>>> _______________________________________________ >>>> Talk-transit mailing list >>>> [email protected] >>>> http://lists.openstreetmap.org/listinfo/talk-transit >> >> > > > _______________________________________________ > Talk-transit mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/talk-transit > > > > _______________________________________________ > Talk-transit mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/talk-transit > _______________________________________________ Talk-transit mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-transit
