I've just done a quick render of what was extracted from the West Mids
data set - http://dev.openstreetmap.org/~edgemaster/naptan/
2009/4/1 Roger Slevin ro...@slevin.plus.com:
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-westmidlands@openstreetmap.org;
talk-tran...@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 list’s 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-westmidlands@openstreetmap.org; talk-tran...@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. It’s 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. It’s 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 can’t 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. That’s
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 – that’s 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 we’re OK by surveying and tagging the
physical
one with Andy’s 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 – I’m of the view that as long the bus stop has
more or less the right relationships to its surroundings then that’s 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
doesn’t exist?
11. Can’t find any nodes for taxi ranks – not imported or doesn’t exist
for Birmingham or I’m not looking hard enough?
12. For the few nodes where I’ve estimated the fit between OSM and
NaPTAN
to be “good enough” I’ve 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.
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--
Regards,
Thomas Wood
(Edgemaster)
--
