[Talk-transit] London Bridge

Frankie Roberto frankie at frankieroberto.com
Fri Sep 18 19:00:45 BST 2009


2009/9/18 Peter Miller <peter.miller at itoworld.com>


> > I've been pondering micro-mapping the carstop signs to mark where the
> > front of the train stops.
> > Indeed, I tried to collect this info for Wimbledon, but the GPS there
> > was too poor also.
>
> Sounds good.
>
> How about the following:-
>
> A railway=stop node for the point on the track where the front of the
> train should stop.
>

I had thought that generally, we've been adding the stop point nodes
(railway=stop) at the point there middle of the train stops, rather than the
front of them. Although, to be honest, it's probably rarely that accurate.
However, when mapping terminus stations, I've been placing the nodes
somewhere approximating the middle, rather than at the last node on the line
(which I guess would represent the buffers anyway).


> Using railway=platform (linear way) for each platform (parallel to the
> track)
>
> Then a platform=boarding_point node for each car-stop sign on the
> platform way with the carriage number - possibly multiple ones per
> platform
>

Crikey, I hadn't considered carriage-level mapping! The problem with this is
that big stations tend to have lots of different lengths of trains stopping
at different spots, so it's not always that consistent (even the platform
number at which a particular service stops at isn't that consistent).


> For a lift we use a node with multiple layer numbers highway=lift?
> layer=0,1,2?
>

I think the convention is for semi-colon separated values rather than
comma-separated (although why the API doesn't support multiple values
natively is puzzling).


> I have been trying to capture most of this on the Stop Area proposal -
> not so much a proposal as a description of good practice:-
> http://wiki.openstreetmap.org/wiki/Proposed_features/Stop_Area
>

I've been trying to follow your proposal as much as possible when mapping
some stations. The main things I've done differently are:

* using railway=stop rather than railway=stopping_point  (this started out
as a mistake, but I stuck with it, as I think it's easier to remember if it
matches the role of 'stop' on the relation)
* I've added site=railway_station to the relation, but also railway=station.
Not sure if we need this redundancy, or whether it's better to follow the
type=site, site=* pattern or the established railway=station tag).
* Using operator=* rather than Authority=*  to follow the convention from
elsewhere.
* I've forgotten to use role=access for the platforms. Do we actually need
this?
* I've not sub-divided any platforms. If there's an island platform with
four different references (eg "2a, 2b, 3a, 3b") I've just given it the name
of "Platforms 2 & 3".  Am still not sure how best to associate platform
numbers with the railway=stop points...

Frankie

-- 
Frankie Roberto
Experience Designer, Rattle
0114 2706977
http://www.rattlecentral.com
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