<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 31 Mar 2009, at 23:43, Andy Robinson (blackadder-lists) wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Roger Slevin [<a href="mailto:roger@slevin.plus.com">mailto:roger@slevin.plus.com</a>] wrote:<br><blockquote type="cite">Sent: 31 March 2009 11:20 PM<br></blockquote><blockquote type="cite">To: 'Andy Robinson (blackadder-lists)'; 'Brian Prangle'; Talk-gb-<br></blockquote><blockquote type="cite"><a href="mailto:westmidlands@openstreetmap.org">westmidlands@openstreetmap.org</a>; <a href="mailto:talk-transit@openstreetmap.org">talk-transit@openstreetmap.org</a>; 'Thomas<br></blockquote><blockquote type="cite">Wood'<br></blockquote><blockquote type="cite">Subject: RE: [Talk-transit] [Talk-gb-westmidlands] Naptan alignment<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Andy<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">"Custom and Practice" stops - that is stops which are not physically marked<br></blockquote><blockquote type="cite">- are a common feature in many parts of the country ... less so within<br></blockquote><blockquote type="cite">Metropolitan areas than in rural ones. And many are not "signed in one<br></blockquote><blockquote type="cite">direction to represent both directions" - they are without any sign. These<br></blockquote><blockquote type="cite">unmarked stops are stop type CUS in NaPTAN. I appreciate that their<br></blockquote><blockquote type="cite">representation on a map might be conceptually challenging ... but they are<br></blockquote><blockquote type="cite">essential points as far as bus passengers are concerned!<br></blockquote><br>I have no problem representing them on a map and indeed the whole concept is<br>fine. Our challenge is one of verification. We essentially only put data in<br>OSM that is physically there on the ground. However at least these stops<br>have the "CUS" tag so it should be possible to verify that busses stop at<br>the location and the evidence on the ground might then be the pile of fag<br>ends in the gutter ;-)</div></blockquote><div><br></div>I would have thought that in the UK the 'verification' of a customary stop could initially be that the data is within NaPTAN and that it doesn't seem unreasonable (ie it is not on a one-way street). Cigarette ends and people standing around looking up the road might corroborate that information but I suggest that they are not necessary where NaPTAN has provided data.</div><div><br></div><div>We should note that this import is getting attention from professionals and that in the UK/ Transmodel because it is seen as 'The' essential link between the timetables and the physical world and they have seen and discussed a lot of unusual situations that need to be accommodated in the past 10 years. I would suggest therefore that we see if we can accommodate their requirements.</div><div><br></div><div>Could I suggest that normally a bus-stop will be a pole, a shelter, a customary stop or a combination of a pole/shelter combination where the elements are close together and where the bus stops near that node and the stop can be modelled using a single node at that point with the appropriate tags. However, In situations where the stopping position (as indicated by a lay-by, paint on the road or a section of raised curb) is different from the position of the shelter then the bus stop should be shown at the point where people enter the vehicle and that the shelter/pole should be mapped as a separate feature?</div><div><br></div><div>There are probably a couple of reasons that the professional community is interested in this detail. Firstly with GPS tracked buses it is importation to know if the bus is crawling towards the bus stop through traffic and should be shown on the electronic sign as 'due' or if it is at the bus stop, or if it is crawling away from the stop through traffic and should not be displayed. Also... with GPS tracked buses the time that it 'arrived' at the stop and 'left' the stop are both recorded for management purposes and bus companies can be fined £100K+ for failing to meet required timings so this is a matter of great importance to them! The other reason to be concerned about this is for blind/partially sighted.</div><div><br></div><div>I note that there is no aerial photography for Birmingham from yahoo. I also note from <a href="http://sautter.com/map">http://sautter.com/map </a>that the alignment for roads in Bham on OSM is out by significant distances in some places when compared to TeleAtlas data on Google maps and that the TeleAtlas data aligns with the aerial photography on Google so it looks as though some roads in central Bham on OSM are slightly out for understandable reasons. This means that in some cases we will will need to move NaPTAN stops to the 'wrong' geolocation to get them to match correctly with the roads which is a shame. In other cases it is clear from looking at NaPTAN data on top of google aerial photography that the NaPTAN stops are already in the wrong position - sometimes the stops are offset back from the road and on other occasions they are incorrectly positioned along the road.</div><div><br></div><div>So.... what is we were able to find someone to pay for rectified Digital Globe satellite photography for Bham to allow the detailed street geometry for the area in OSM to be corrected? The cost of this for the 700 sq km that makes up most of Bham would be able £6K. If that would be useful to OSM then possibly someone in the local transport authority or DfT could be persuaded to provide the necessary funds to purchase this, however the first question is if that would be appreciated and used by the local OSM community. I certainly found it useful in Ipswich to use yahoo aerial photography to adjust my physical survey and spot missing streets in my initial survey - and OSM and TeleAtlas are now much closed together for road alignment in Ipswich using sautter as a result. This seems to be the only practical and legal way to get the data right for NaPTAN and for OSM in Bham.</div><div><br></div><div>By way of reassurance, yes you can use the DG photography to derive mapping, but you can't use the DG photography within public facing products itself for that price. We used this approach for the Gaza project and it worked fine. Here are some more details:</div><div><a href="https://www.swiftpage6.com/speasapage.aspx?X=2Y0QTEPLHQPGU9KC00Z5WD">https://www.swiftpage6.com/speasapage.aspx?X=2Y0QTEPLHQPGU9KC00Z5WD</a></div><div><br></div><div><br></div><div><br></div><div>Regards,</div><div><br></div><div><br></div><div>Peter</div><div><br></div><div><br></div><div> </div><div><br></div><div><br></div><div><br></div><div> <br><blockquote type="cite"><div><br><br>Cheers<br><br>Andy<br><br><blockquote type="cite"><br></blockquote><blockquote type="cite">Roger<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">-----Original Message-----<br></blockquote><blockquote type="cite">From: <a href="mailto:talk-transit-bounces@openstreetmap.org">talk-transit-bounces@openstreetmap.org</a><br></blockquote><blockquote type="cite">[<a href="mailto:talk-transit-bounces@openstreetmap.org">mailto:talk-transit-bounces@openstreetmap.org</a>] On Behalf Of Andy Robinson<br></blockquote><blockquote type="cite">(blackadder-lists)<br></blockquote><blockquote type="cite">Sent: 31 March 2009 23:11<br></blockquote><blockquote type="cite">To: 'Brian Prangle'; <a href="mailto:Talk-gb-westmidlands@openstreetmap.org">Talk-gb-westmidlands@openstreetmap.org</a>;<br></blockquote><blockquote type="cite"><a href="mailto:talk-transit@openstreetmap.org">talk-transit@openstreetmap.org</a>; 'Thomas Wood'<br></blockquote><blockquote type="cite">Subject: Re: [Talk-transit] [Talk-gb-westmidlands] Naptan alignment<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Using <a href="http://sautter.com/map">http://sautter.com/map</a> I did a comparison of the precisely positioned<br></blockquote><blockquote type="cite">stops I mapped this morning in the Aldridge area. Assuming Google has the<br></blockquote><blockquote type="cite">locations the same as the NaPTAN data then I would say about one in 5<br></blockquote><blockquote type="cite">NaPTAN<br></blockquote><blockquote type="cite">stops has something wrong with the location. Mostly a stop is displaced<br></blockquote><blockquote type="cite">along the street. These errors are as much as 30m.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">One interesting question relates to stops on the ground that exist only on<br></blockquote><blockquote type="cite">one side of the street but state they also pickup/drop on the opposite side<br></blockquote><blockquote type="cite">of the street. The NapTan data contains two stops when on the ground there<br></blockquote><blockquote type="cite">is only one physical (pole or shelter). In general the NaPTAN data appears<br></blockquote><blockquote type="cite">to show the stops staggered on either side of the street when in practice<br></blockquote><blockquote type="cite">passengers are going to wait opposite the bus stop sign/shelter. At the<br></blockquote><blockquote type="cite">moment I'm mapping these with one node and an opposite=yes tag on them.<br></blockquote><blockquote type="cite">There is no way to map the stop on the opposite side as it doesn't<br></blockquote><blockquote type="cite">physically exist. So what to do about the NaPTAN data in this case.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Cheers<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Andy<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><blockquote type="cite">-----Original Message-----<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">From: talk-gb-westmidlands-bounces@openstreetmap.org [<a href="mailto:talk-gb-">mailto:talk-gb-</a><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="mailto:westmidlands-bounces@openstreetmap.org">westmidlands-bounces@openstreetmap.org</a>] On Behalf Of Brian Prangle<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Sent: 31 March 2009 9:46 AM<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">To: <a href="mailto:Talk-gb-westmidlands@openstreetmap.org">Talk-gb-westmidlands@openstreetmap.org</a>; talk-<br></blockquote></blockquote><blockquote type="cite"><a href="mailto:transit@openstreetmap.org">transit@openstreetmap.org</a>;<br></blockquote><blockquote type="cite"><blockquote type="cite">Thomas Wood<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Subject: [Talk-gb-westmidlands] Naptan alignment<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Thomas<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">I've also looked at Google maps and their alignment is off too in exactly<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">the same way ours is in areas I know well and have surveyed, so I guess<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">it's down to the NaPTAN data. There are examples where I know the bus<br></blockquote></blockquote><blockquote type="cite">stops<br></blockquote><blockquote type="cite"><blockquote type="cite">are in a row along the street (Corporation Street and Acocks Green<br></blockquote></blockquote><blockquote type="cite">Village<br></blockquote><blockquote type="cite"><blockquote type="cite">for example) but NapTAN has one or two skewed from the line by several<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">metres. Currently I favour correcting the NapTAN data to what we know on<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">the ground, but until a consensus emerges I'm laying off the urge to<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">correct it.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Regards<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Brian<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">Talk-transit mailing list<br></blockquote><blockquote type="cite"><a href="mailto:Talk-transit@openstreetmap.org">Talk-transit@openstreetmap.org</a><br></blockquote><blockquote type="cite"><a href="http://lists.openstreetmap.org/listinfo/talk-transit">http://lists.openstreetmap.org/listinfo/talk-transit</a><br></blockquote><blockquote type="cite"><br></blockquote><br><br><br>_______________________________________________<br>Talk-transit mailing list<br><a href="mailto:Talk-transit@openstreetmap.org">Talk-transit@openstreetmap.org</a><br>http://lists.openstreetmap.org/listinfo/talk-transit<br></div></blockquote></div><br></body></html>