I share the concern that mapping parties create unmaintained data in the
same way as imports or armchair mapping. However, the argument only goes so
far: much of our original data was boot-strapped by such methods (notably
NPE map & later OS StreetView). For places in the North West of England
on-the-ground surveyed data is often close to non-existent.

Take for instance any of the following, Bolton, Bury, Rochdale, Oldham,
Ashton-under-Lyme, Liscard (Wallasey), Birkenhead, St Helens, Wigan,
Denton, Hyde, Altrincham, Blackburn, Burnley etc. Not only are shops
missing but probably many other significant POIs. For instance in visits to
Coalville, Melton, Hoylake & New Brighton I was able to add at least 5
unmapped pubs & (lest any one accuse me of being pub-centric) a similar
number of post-boxes, oneway streets etc.

Nothing is a substitute for local on-the-ground mappers (look at the
difference Alex Kemp has made to the East side of Nottingham), but a few
on-the-ground surveys can drastically improve how a place is mapped,
particularly if the information can be shared through things like
Mapillary. So we can move data from remotely mapped to checked
on-the-ground, which ought to bring many improvements.

Also, I have always maintained the primary value is collect good quality
address data which is more permanent. Collecting addresses in town centres
is non-trivial as many premises do not show addresses and the complex
building history doesn't help.

Adding the shops is necessary and makes the process much more interesting
for the mapper. It's important that the actual buildings be added not just
shop nodes. It's also important to be as systematic as possible: better to
capture several streets in their entirety than map some shops across the
whole town. I find it very difficult to resolve issues (such as closed
shops, inaccurately located nodes etc) if there are gaps in the data (hence
shop=vacant). This is fairly noticeable in Manchester city centre: there is
a decent density of POIs, but they have not been collected systematically,'

I'm actually in a position to look at degree of change as I did some
surveying in Stockport town centre on Saturday almost exactly a year since
my last visit. My impression is that the overall scope of change in shops
is quite minor: by far and away the most significant being BHS. I'll get a
better idea when I've completed this year's edits. I have some older FHRS
files so I may be able to quantify this for that data.

I'd love to know how to attract more mappers in places like the North West
of England (or indeed coastal towns anywhere in GB), but I don't think any
of us do. What I do know is that it was a convenience store placed on the
wrong street corner which piqued Alex's original interest.

Jerry


On 13 September 2016 at 23:36, Dan S <danstowell+...@gmail.com> wrote:

> Town-centre blitzes can lead to out-of-date data very quickly. Town
> centre data is better to have in OSM if it has maintainer(s). Jerry
> acknowledged this, but I still would like to register a concern about
> that!
>
> Best
> Dan
>
> > ... <Talk-GB@openstreetmap.org>
> > https://lists.openstreetmap.org/listinfo/talk-gb
> >
>
> _______________________________________________
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> Talk-GB@openstreetmap.org
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>
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