[Talk-GB] Potentially incompatible edits in West London

[Andy Townsend]

Hello - especially to mappers in London.  Andy from OSM's Data Working 
Group here.

There's been a suggestion that mapper that has been very active in West 
London* https://www.openstreetmap.org/user/Mikhail1412 has been using 
various sources that aren't compatible with OSM. Attempts to contact the 
mapper via 
http://resultmaps.neis-one.org/osm-discussion-comments?uid=2055614 have 
mostly been unsuccessful, although a local mapper has managed to get 
replies to some private messages (which unfortunately do also suggest 
that they're using incompatible sources).  It has been suggested that 
https://www.openstreetmap.org/user/Mik1412 is another account by the 
same person.

Attempts by the DWG to get the mapper to interact with the community 
have failed: https://www.openstreetmap.org/user/Mikhail1412/blocks , 
hence a "block until they engage with us" message at 
https://www.openstreetmap.org/user_blocks/5919 .

I had hoped that we'd be able to revert and redact certain classes of 
data only (see e.g. comment on 
https://www.openstreetmap.org/changeset/113072980 ).  However, the 
problematic changes include geometric changes too - it has been said 
that the latest change to https://www.openstreetmap.org/way/144667839 
(see the top-right corner of 
https://overpass-api.de/achavi/?changeset=113007152 ) isn't possible 
based on imagery available to OSM because of tree cover.  That edit is 
unlikely to be based on survey as the mapper concerned apparently hasn't 
been in London since late 2019 (due to the pandemic etc.).  Some other 
changes seem to match Google Street View and not a more recent survey.

It therefore looks like we'll have to revert (and likely redact) most or 
all of this mapper's changes since the beginning of 2020, unless we get 
a reason not to from a reply to 
https://www.openstreetmap.org/user_blocks/5919 .  I'm sending this 
message for a few reasons:

* to encourage mappers in West London to comment on this user's 
changesets, both where the data appears not to be based on sources 
available to OSM but also where it can be validated by e.g. survey.  I 
don't expect that you'll get a reply, but those comments will be 
extremely useful to us and to everyone else in the area.

* to give everyone a chance to tell me if I've got anything wrong 
(please reply on this list if that's the case).

* to give everyone a bit of a warning of a potential "hole" appearing in 
the data in West London in a few days time.

I won't start any wide-scale revert for a week or so to give the mapper 
concerned yet another chance to reply.  I have already reverted (and 
redacted) some changes in 
https://www.openstreetmap.org/changeset/115296538 where there were 
specific reports about individual pieces of data.

Best Regards,

Andy

* more recently the same mapper has been active in France - I've also 
asked them for the sources of their edits there.