[Talk-transit] Naptan import

[Roger Slevin]

Christoph

Thanks - if that's the case then I need to look again at the definition of this particular zone .... I had alerted the people who had created the data a long time ago that it could be defined much more simply.  So let me check why this hasn't happened.  From memory it should only need about 12 points defining a "blob" rather than the very strange detail that is being defined by the more extensive list of points that I now see is still in the source data.

Roger


-----Original Message-----
From: talk-transit-bounces at openstreetmap.org [mailto:talk-transit-bounces at openstreetmap.org] On Behalf Of Christoph Böhme
Sent: 02 August 2009 11:40
To: talk-transit at openstreetmap.org
Subject: Re: [Talk-transit] Naptan import

"Roger Slevin" <roger at slevin.plus.com> schrieb:

> Plusbus zones are polygons which are unrelated to the road network -
> so for Rye it covers a large polygon defined by straight lines
> linking each pair of adjacent nodes on the source list of defining
> points.  The representation of this "along the roads" is
> inappropriate - and certainly not how it should be should be shown in
> terms of the zone definition intended.

The representation of the plusbus zones in OSM is still as it should be.
Except for merging duplicate nodes they are the same as defined in the
NPTG data. I just tried to describe why the zone for Rye has such an
unusual shape compared to other zones. I didn't modify it to actually
follow the roads. Sorry for causing confusion!

Christoph

> The Rye example is a particularly extreme example, as there are few
> roads in the area with bus routes - and lots of marshland and open
> countryside covered by the Plusbus zone.
> 
> Roger
> 
> -----Original Message-----
> From: talk-transit-bounces at openstreetmap.org
> [mailto:talk-transit-bounces at openstreetmap.org] On Behalf Of
> Christoph Böhme Sent: 02 August 2009 00:24 To: Thomas Wood
> Cc: Public transport/transit/shared taxi related topics
> Subject: Re: [Talk-transit] Naptan import
> 
> Thomas Wood <grand.edgemaster at gmail.com> schrieb:
> 
> > 2009/7/30 Christoph Böhme <christoph at b3e.net>:
> > > Thomas Wood <grand.edgemaster at gmail.com> schrieb:
> > >> 2009/7/29 Christoph Böhme <christoph at b3e.net>:
> > >> > I transformed the Plusbus Zones into a josm-file (XSLT is
> > >> > cool :-). Thomas can you import it using the naptan-user if no
> > >> > one objects to the tagging scheme?
> > >> >
> > >> > http://www.mappa-mercia.org/nptg/plusbuszones.osm.gz
> > >> >
> > >> > Cheers,
> > >> > Christoph
> > >> >
> > >> > _______________________________________________
> > >> > Talk-transit mailing list
> > >> > Talk-transit at openstreetmap.org
> > >> > http://lists.openstreetmap.org/listinfo/talk-transit
> > >> >
> > >>
> > >> That looks fine, the only issue is that none of the polygons are
> > >> closed!
> > >
> > > Oh, good that you noticed this. I fixed the file and uploaded it
> > > again.
> > >
> > > Christoph
> > >
> > 
> > I have run JOSM's validator over it to clean up some duplicate ways,
> > and the more obviously incorrect polygon geometries (West Mids had a
> > weird doubleback by the look of it) a few have overlapping segments,
> > but I've chosen to ignore their 'errorness'.
> > 
> > http://www.openstreetmap.org/browse/changeset/2008301
> 
> Good idea to use JOSM's validator, I should have done it myself ...
> 
> The incorrect geometries are converted directly from the NPTG data.
> Some of the polygons there have duplicate nodes. Removing the
> duplicate nodes was a sensible choice, I think. I had a look at the
> very distorted Plusbus Zone for Rye. Its strange shape seems to stem
> from the fact that it simple spans four villages and follows the road
> between them. I think there are similar reasons for the other errors.
> 
> Thank you checking and importing the changeset!
> 
> Christoph
> 
> > -- 
> > Regards,
> > Thomas Wood
> > (Edgemaster)
> 
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> 
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