Thomas Ok - thanks. I will get a close approximation to this by using current data with the same filtering criterion - and hopefully, if there are further questions about any specific aspects of the data, I will be able to respond to them.
Roger -----Original Message----- From: Thomas Wood [mailto:grand.edgemas...@gmail.com] Sent: 01 April 2009 18:15 To: ro...@slevin.plus.com Cc: Brian Prangle; talk-gb-westmidla...@openstreetmap.org; talk-transit@openstreetmap.org Subject: Re: [Talk-transit] NaPTAN bus stop database import - some moreobservations 2009/4/1 Roger Slevin <ro...@slevin.plus.com>: > I would be able to comment more about the missing data and other aspect > which you and others draw to the lists attention if I could have a copy of > the NaPTAN data that has been put through the import process can you (or > someone else on the list) either point me to where I can find that specific > data set or can send me a copy of the specific data that has been > imported? > Currently all data as of 25th March 2009 19:47:46 in the West Midlands region with the a value of Birmingham (case insensitive) in the Town field. I am planning to check to see if we missed any stops, and add any missed based upon a bbox matching. > > Best wishes > > Roger > > ________________________________ > > From: talk-transit-boun...@openstreetmap.org > [mailto:talk-transit-boun...@openstreetmap.org] On Behalf Of Brian Prangle > Sent: 01 April 2009 13:41 > To: talk-gb-westmidla...@openstreetmap.org; talk-transit@openstreetmap.org > Subject: [Talk-transit] NaPTAN bus stop database import - some > moreobservations > > > > Some more views and observations on the NaPTAN data import in Birmingham: > > 1. It serves as a great QA on OSM data and shows that in the City > Centre where we have not been able to get decent GPS traces more accuracy is > needed so the potential of obtaining aerial photography is great. > > 2. Its a great impetus to resurvey streets where earlier work > (potentially inaccurate from NPE tracing, older GPS devices, less points > collected, inexperience, not realising that roads have a width greater than > the rendered line so placing bus stops too close to the road etc.) can be > improved. > > 3. Its also a great impetus to improve practice on surveying bus > stops and be much more precise and comprehensive also a stimulus to edit > all those old bus stops where we placed them as a node on the way rather > than to the side of ways which is our current practice. > > 4. QA works both ways and our surveys should help to improve NaPTAN > data. > > 5. As an exercise(excuse the pun!) I cycled from Acocks Green to > Moseley and back this morning along the No 1 bus route and surveyed 47 bus > stops each time standing at the pole(leaning against it you cant get > closer than that!) or underneath the plate at a shelter: 4 bus stops > coincided within 3-4 m; 17 were good enough coinciding <8-10m. Thats > approx 45%. The rest were out by anything up to 90m or were just missing. > > 6. I think either the pole where there is no shelter or the bus stop > plate at a shelter should be what we survey thats where the > identification of what we survey is located > > 7. Where a physical stop on one side of the road doubles up for one on > the other side also I think were OK by surveying and tagging the physical > one with Andys suggestion of a tag opposite=yes. The NaPTAN untagged node > on the other side can be left in place to indicate the logical > relationship. > > 8. I like the idea of tagging where the bus stop is set back in a > lay-by from the road which might account for some NaPTAN nodes being some > distance from the road > > 9. For our purposes good enough is probably sufficient rather than > precise positional detail Im of the view that as long the bus stop has > more or less the right relationships to its surroundings then thats OK. > > 10. Surprised that there is no data for either the closed Digbeth Coach > Station which is being rebuilt or the temporary replacement nearby. I > thought we were importing off-street bus stops? Perhaps the NaPTAN data > doesnt exist? > > 11. Cant find any nodes for taxi ranks not imported or doesnt exist > for Birmingham or Im not looking hard enough? > > 12. For the few nodes where Ive estimated the fit between OSM and NaPTAN > to be good enough Ive merged the nodes deleting the unverified tag and > editing source tag to v=naptan_import;survey > > 13. Verifying the data is going to be a long, slow process with a lot of > resurveying needed. > > _______________________________________________ > Talk-transit mailing list > Talk-transit@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-transit > > -- Regards, Thomas Wood (Edgemaster) _______________________________________________ Talk-transit mailing list Talk-transit@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-transit
