[Talk-GB] NaPTAN Data

[Ed Loach]

Jay wrote:
> I have a few questions regarding the 2009 NAPTAN import. 

> Sadly, much of the UK hasn't been touched since the NaPTAN data was imported. 

To clarify, the whole dataset wasn't originally imported, only selected areas. See
https://wiki.openstreetmap.org/wiki/NaPTAN/Request_for_Import
although elsewhere on the wiki suggests Aberdeen has been done more recently
https://wiki.openstreetmap.org/wiki/NaPTAN/Aberdeen

> I don't really know how to analyse the data of the other 65% but I'll place a bet it's not in a great state. Additionally, 95% of all `naptan:verified` tags are `no`.

I am one of those that removes the tag after a survey, but if I encounter a bus stop with a tag on and can align it better based on the aerial imagery we didn't have in 2009 I leave the tag value set to "no". Verified really requires a visit for things like determining whether there is a timetable case/raised kerb/shelter/bench/waste_basket and all those other attributes that are gathered when verifying the naptan location/stop name/bus stop type/status.

> I want to know if it's possible to reimport/mass update NaPTAN data from the latest set of information. 

I'm not sure this is a good idea, at least nationwide. Essex was up-to-date as at fairly late last year (based on me having checked all the bus routes were up to date - a manual process of comparing the opendata to what was mapped in OSM, with a utility program I wrote to display the two sets of data side by side to help). I'm pretty sure the West Midlands are fairly up-to-date too (when checking bus routes near my parents house in Wolverhampton all the stops seemed to be there already - in Essex there were quite a few new ones that needed adding, such as where roads have been re-routed or new build housing estates have gone in).

> Additionally, I propose a few extra tags;
>  - `source:date=*` with the `ModificationDateTime` field within the NaPTAN datasets so we have a good idea of when the data was last touched.

I would suggest naptan:RevisionNumber would be easier to use to be able to simply compare the values in OSM to Naptan to spot any that have changed easier.

>  - `public_transport=*` because... well yeah. We have that now. We didn't in 2009.

I have added this tag when updating bus route relations to PT v2.

>  - `unsigned=yes` for bus stops with BusStopType=CUS because it's defined as "Unmarked stop (or only marked on the road). Point footprint.". Previously, these stops weren't tagged with highway=bus_stop and I think we should add those en-mass too. Leaving those tags off has led to confusion with mappers unfamiliar with NaPTAN and caused the nodes to be blindly deleted or merged into other objects.

This can't be assumed. That is what CUS is supposed to mean, but I've encountered signed CUS stops and adding unsigned=yes or physically_present=no still really should require a survey. I know of one stop that remained part of a time-tabled bus route even though the road got permanently diverted and the old route where the stop was became a shared use cycle way (new stops were added on the new route for the road). I would be tempted to add public_transport=platform and leave highway=bus_stop/unsigned=yes for a survey. Similarly the naptan status of "del" might not mean physically removed, just no longer used. There are also bus stops I have encountered that exist on the ground and aren't in naptan (or are part of any current bus route, so probably last used before the database got computerised).

You also need local knowledge. For example West Midlands stops (ATCOcode starting 4300) are labelled with the naptan Street Name *and* naptan Common Name field. In Essex it is just the Common Name field on the stops I have physically checked. Different styles might be used elsewhere.

I would suggest updating the stops in your local area that were originally imported and still at version 1 (so not edited at all) should be fine. Any others should be compared manually to see what has changed. When I have added new stops I've only added the atcocode and naptancode tags (and type if not MKD, and status if not act), and naptan:verified=no to show they've not been physically surveyed, such as this stop that I surely must have caught on Mapillary at some point... https://www.openstreetmap.org/node/6253620921 Looks like in 2015 it was only a raised kerb, but I'm sure it is marked with a post and flag these days. https://www.mapillary.com/map/im/Y_nhMUIUB9ja9HZ9KHkYPA - I'll have to revisit.

Ed