[Talk-transit] Naptan import

Roger Slevin roger at slevin.plus.com
Sun Aug 2 07:30:26 BST 2009


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 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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