[Talk-transit] (no subject)

Peter Stoner stonerpj at mytraveline.info
Tue Aug 25 20:34:46 BST 2009


pics'	 <talk-transit at openstreetmap.org>
Subject: Re: [Talk-transit] Naptan import
Date: Wed, 29 Jul 2009 19:16:17 +0100
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The impression I have got from editing NPTG is that the source data was =
probably 1960s.  So I don't think too much would be gained from comparing =
with NPE.

You might do better to analyse the difference between the NPTG numbers =
which start in E (existing) and the ones created subsequenty which start in =
N (new).

Best wishes

--
Peter Stoner

-original message-
Subject: Re: [Talk-transit] Naptan import
From: Christoph B=C3=B6hme <christoph at b3e.net>
Date: 29-07-2009 18:30

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

> Christoph
>=20
> Sorry - I now realise I shouldn't have referred to "inactive"
> localities ... this is something I can see on the editor system for
> NPTG, but the export only shows the active localities ... the =
records
> of the inactive ones are not included in the standard XML file.  I
> would need to check whether it is possible to get an extract from
> NPTG which includes inactive records (or only comprises the =
inactive
> ones) - but that is a question I will only ask if someone can =
suggest
> that some useful purpose could be served by having access to that
> data.

The only reason for using the inactive data I can see is a comparison
with OSM-only places. This could indicate NPTG places which might =
have
been deactivated because they are not part of the public transport
network. Unless we want to add data from NPTG to existing OSM stops
(e.g. the locality code) this information is probably more relevant =
to
the DoT than OSM.

However, since places in OSM might be derived from NPE maps, OSM-only
places could also mean that the locality has been abandoned in the =
time
since 1950. Your brief history of NPTG indicates to me that the data =
is
probably much more recent then NPE's 1950 data. It might therefore be
interesting to know which places are only in OSM and not even in the
inactive NPTG data. Such places have then probably been abandoned a
long time ago.

Christoph

> Roger
>=20
> -----Original Message-----
> From: Christoph B=C3=B6hme [mailto:christoph at b3e.net]=20
> Sent: 28 July 2009 22:54
> To: roger at slevin.plus.com; Public transport/transit/shared taxi
> related topics
> Cc: roger at slevin.plus.com; 'Peter Miller'
> Subject: Re: [Talk-transit] Naptan import
>=20
> Roger,
>=20
> thank you for your explanations.
>=20
> "Roger Slevin" <roger at slevin.plus.com> schrieb:
>=20
> >  Although NPTG was originally for public transport purposes, we
> > stressed at all times that a locality should be listed even if it
> > has no public transport - but we know that some local editors =
have
> > probably erred towards marking some unserved rural hamlets as
> > "inactive".=20
> >=20
> > All "inactive" localities should still be in the data - so =
hamlets
> > which are missing may be in NPTG, but marked as "inactive". =20
>=20
> What would an inactive entry look like in the data? The xml schema
> does not seem to define any elements/attributes for inactive =
entries.
>=20
> > However they may simply never have been in the source data - and =
no
> > one to date has recognised the need to add them to NPTG.  It =
would
> > be interesting to see what localities OSM holds in its data which
> > are not included in NPTG (as well as the reverse of this) if that =
is
> > possible.
>=20
> I created two tables of OSM- and NTPG-only places:
>=20
> http://www.mappa-mercia.org/nptg/nptg-only-localities.csv.gz
> http://www.mappa-mercia.org/nptg/osm-only-localities.csv.gz
>=20
> I considered a place to be only in one dataset if no place from the
> other dataset exists in its proximity which has the same name.
> Proximity was defined as an euclidian distance less than 0.3 =
between
> the lat/lon positions of the places (I don't know how this relates =
to
> kilometres/miles). Since the OSM data contains some nodes with
> place-tags that have nothing with actual places, I only included =
nodes
> with a place-value of either locality, island, suburb, hamlet,
> village, municipality, town or city. I also excluded place=3Dfarm.
>=20
> 	Christoph
>=20

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