[Talk-GB] worrying edit to junction (now reverted)

[Andy Townsend]

On 20/01/2021 14:34, Tom Hughes wrote:
> On 20/01/2021 12:22, Andy Townsend wrote:
>
>> https://www.openstreetmap.org/user/VLD071 doesn't mention Facebook 
>> directly either, but does mention's Facebook's "black hole" address 
>> "osm at fb.com".
>
> He also says he's working on their AI mapping but the wiki page he
> refers to doesn't mention the UK and it's hard to see why they would
> want to let it loose on a well mapped country or why it would be a
> good idea to do so.
>
> My main question is, what exactly led to them armchair mapping a
> junction in a well mapped area of London? I can understand that
> once they were looking at it they mistakenly used out of date
> imagery, but what led to them looking at it in the first place...

All the examples I've seen of "Facebook_AI-Assisted_Road_Tracing" 
(whether done by Facebook or by other mappers) in the UK have been 
problematical, for a couple of reasons. One reason is that any actual 
roads have already been added pretty much everywhere in the UK, and if 
there's something detected as "new", it's likely a false positive, or 
something not really worth adding (for example, I've seen gaps between 
lorries in agricultural stackyards added as "roads" this way)

Another is that FB's "detected roads" are based on an old Esri layer, 
and seem to be offset wherever it is used. 
https://overpass-turbo.eu/s/12Be is the originally added position (in 
this case by an Amazon mapper using Facebook's "AI") of a concrete track 
in a sewage works up the road from me.  It's not offset by much, but 
it's enough to be annoying.  Exactly why an Amazon mapper expected to be 
delivering parcels around the back of a sewage works (inside a locked 
gate) I have no idea.

Best Regards,

Andy