On Thu, Apr 18, 2013 at 3:02 PM, Chris Hill <[email protected]> wrote:
> On 18/04/13 14:14, Shaun McDonald wrote: > >> On 18 Apr 2013, at 13:01, "Dave F." <[email protected]> wrote: >> >> On 18/04/2013 12:52, Shaun McDonald wrote: >>> >>>> Updates are a lot harder to do as you have to deal with differences >>>> >>> When you say differences, do you mean within the tags? Does it need to >>> do that, could it not do a simpler find & replace? >>> >> If someone has modified the item in OSM and in NaPTAN then it needs >> manual intervention as to which is more correct - the one in OSM or the one >> in NaPTAN. >> >> Shaun >> >> >> There are various errors in NaPTAN data. The data was created by > different means in different local authorities and to varying standards of > quality. The position is not always very accurate, but sometimes the > accompanying information can be poor too. Some data are very good, but > until you survey it you just don't know. As someone who has manually > validated every stop in in a city (~1300) and about a third (~900) of the > stops in a large Unitary Authority I can vouch for the differences and the > wide variation in quality. It became clear that in the city the quality > varied from area to area. I suspect that some areas were surveyed or > recorded or checked more diligently than others possibly because a more > diligent or competent person did the work there. > Can I ask what type of changes you made to the NaPTAN data when manually validating the stops? I've been meaning to look at exactly this - updating the NaPTAN imported data - for a little while now as it's needed before the TNDS data (which has route / timetable info) can be usefully used. My rough plan was to assume that all tags under the naptan: namespace were fair game for updating to match the current NaPTAN import. Whether that's practical will depend on if there have been widespread manual changes to the naptan: data or not. Oliver
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