[Talk-transit] [Talk-gb-westmidlands] Naptan alignment

Andy Robinson (blackadder-lists) ajrlists at googlemail.com
Tue Mar 31 23:11:16 BST 2009

Using http://sautter.com/map I did a comparison of the precisely positioned
stops I mapped this morning in the Aldridge area. Assuming Google has the
locations the same as the NaPTAN data then I would say about one in 5 NaPTAN
stops has something wrong with the location. Mostly a stop is displaced
along the street. These errors are as much as 30m.

One interesting question relates to stops on the ground that exist only on
one side of the street but state they also pickup/drop on the opposite side
of the street. The NapTan data contains two stops when on the ground there
is only one physical (pole or shelter). In general the NaPTAN data appears
to show the stops staggered on either side of the street when in practice
passengers are going to wait opposite the bus stop sign/shelter. At the
moment I'm mapping these with one node and an opposite=yes tag on them.
There is no way to map the stop on the opposite side as it doesn't
physically exist. So what to do about the NaPTAN data in this case.



>-----Original Message-----
>From: talk-gb-westmidlands-bounces at openstreetmap.org [mailto:talk-gb-
>westmidlands-bounces at openstreetmap.org] On Behalf Of Brian Prangle
>Sent: 31 March 2009 9:46 AM
>To: Talk-gb-westmidlands at openstreetmap.org; talk-transit at openstreetmap.org;
>Thomas Wood
>Subject: [Talk-gb-westmidlands] Naptan alignment
>I've also looked at Google maps and their alignment is off too in exactly
>the same way ours is in areas I know well and have surveyed, so I guess
>it's down to the NaPTAN data. There are examples where I know the bus stops
>are in a row along the street (Corporation Street  and Acocks Green Village
>for example) but NapTAN has one or two skewed from the line by several
>metres.  Currently I favour correcting the NapTAN data  to what we know on
>the ground, but until a consensus emerges I'm laying off the urge to
>correct it.

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