[Talk-transit] Naptan import

Christoph Böhme christoph at b3e.net
Wed Jul 29 23:45:16 BST 2009


Roger,

thank you very much, I am looking forward to analysing this. 

Please note that I only have a standard OSM excerpt of places and no
special 1950s dataset. Just in case this has not been made clear in my
previous email.

Cheers,
Christoph

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

> I'll see whether it is possible to get a file exported which includes
> the "inactive" localities and let you know ... there may be some
> value in running a comparison between your 1950s data and the more
> recent data in NPTG.
>
> Best wishes
> 
> Roger
> 
> 
> -----Original Message-----
> From: Christoph Böhme [mailto:christoph at b3e.net] 
> Sent: 29 July 2009 18:36
> To: roger at slevin.plus.com
> Cc: 'Public transport/transit/shared taxi related topics'; 'Peter
> Miller' Subject: Re: [Talk-transit] Naptan import
> 
> "Roger Slevin" <roger at slevin.plus.com> schrieb:
> 
> > Christoph
> > 
> > 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
> > 
> > -----Original Message-----
> > From: Christoph Böhme [mailto:christoph at b3e.net] 
> > 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
> > 
> > Roger,
> > 
> > thank you for your explanations.
> > 
> > "Roger Slevin" <roger at slevin.plus.com> schrieb:
> > 
> > >  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". 
> > > 
> > > All "inactive" localities should still be in the data - so hamlets
> > > which are missing may be in NPTG, but marked as "inactive".  
> > 
> > What would an inactive entry look like in the data? The xml schema
> > does not seem to define any elements/attributes for inactive
> > entries.
> > 
> > > 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.
> > 
> > I created two tables of OSM- and NTPG-only places:
> > 
> > http://www.mappa-mercia.org/nptg/nptg-only-localities.csv.gz
> > http://www.mappa-mercia.org/nptg/osm-only-localities.csv.gz
> > 
> > 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=farm.
> > 
> > 	Christoph
> > 
> 




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