[Talk-transit] Naptan import

Christoph Böhme christoph at b3e.net
Tue Jul 28 22:54:13 BST 2009


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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