[Talk-GB] UK address project update

[Gregory Williams]

On Fri, 2021-11-12 at 20:46 +0000, Rob Nickerson wrote:
> 
[Snip]
> 
> Secondly, having reviewed a few areas for the Green and Red dots, we
> decided that the Red dots (LR Polygons & OS Buildings approach) gives
> a better set of addressable locations.I use the word "better" very
> much in a relative way. Neither approach is perfect but our view is
> that the red points are a little bit closer to what we want. They
> have fewer false positives which likely matters more. We're keen to
> get your view - do you agree? disagree?

I generally agree here. The positions of the red dots, where they
exist, are more reliable. However, as you've noted below, this does
mean that the red dots can be somewhat sparse and random-looking in
areas of council housing.

I'd additionally observe a few other cases I've seen where the green
dots are more useful than the red ones:
- In areas of fresh development. Though I'd also observe that there are
also UPRN points for buildings not yet built. So some caution would be
needed here.
- Areas of university-provided student accommodation
- Some areas of retail development, but this doesn't seem to
universally be the case.
> 
> Finally, where the red points fall short are in dense city centres
> and areas with a high concentration of council houses. This is
> because of a lack of cadastral parcels in these areas (e.g. one large
> cadastral parcel for the whole area rather than individual cadastral
> parcels for each home or business unit). We are keen to get your
> ideas as to how to work around this. So far our ideas are:
>    1. Identify these locations and direct experienced OSMers to them
> (leaving the easy places for the new mappers we hope to attract) to
> add the address by ground survey.
>    2. Or same as 1 but instead of the experienced OSMer having to do
> a ground survey (as might not live locally) allow them to "pull" the
> green dots through into the final user interface so that local people
> new to OSM can collect the address. This could be done by adding
> these to OSM; that is adding points to OSM that just have a UPRN or
> similar tag at first so that they can be made available in the map
> editor we are working on. 
> Feedback and alternate ideas welcomed. I am particularly keen to know
> if you support idea 2 as typically we have avoided this in the past.
> For example we did not add the postcode centroids to OSM. This time
> we can add an addressable location with a UPRN, city, postcode and/or
> street name. The final details (house name / number) would then need
> adding via the crowdsource project.
> 
I'm not particularly keen on option 2. I think there's a risk that it'd
open the floodgates to a large amount of data which may not get
reviewed. The resulting nodes might also get moved without the
consequences of that being fully understood by all mappers, risking
points being linked with the wrong address in the future. I wouldn't
want to risk the overall data quality of OSM; I'd generally favour a
slower approach, but keeping the quality bar higher.

Gregory