[Talk-GB] OSM UK address project: tags - Updated guidance

[Robert Whittaker (OSM lists)]

On Sat, 1 Jan 2022 at 13:05, Rob Nickerson <rob.j.nickerson at gmail.com> wrote:

> Thank you for all the comments received in regards to the addr:* tags and how to apply them to map addresses in the United Kingdom. I shared some thoughts on how to resolve the comments at the time (e.g. my 22 December email [1]). This email is just to confirm that I have now found the time to make all the updates to the wiki page. You can view the updated page at:
>
> https://wiki.openstreetmap.org/wiki/Addresses_in_the_United_Kingdom
>
> I will keep an eye on the replies here and on the wiki Discussion page so feel free to post to either place should you have feedback.

Many thanks for your work on this Rob. I think the new version is
something I can live with. I'm still a little unsure whether defining
a new addr:substreet tag is a good idea, given the issues it could
create, particularly for global data-users, but maybe it's the least
worst option.

There's one minor thing I would like to add/change though to the
current proposal, and that is to make it an error for an object to
have more than one of addr:street, addr:place, addr:substreet and
addr:terrace. (In cases where you might want addr:street and one of
the others, then addr:parentstreet can be used instead of
addr:street.) This change would remove ambiguity over whether to use
addr:substreet+addr:street or addr:substreet+addr:parentstreet, make
it easier to validate addresses and spot errors, could simplify some
of our processing, and makes it easier for other data consumers (who
could then treat addr:substreet exactly as they would treat
addr:street or addr:place). Perhaps most importantly, it also avoids
the issue of a data-user that's unaware of addr:substreet from
incorrectly assigning a house number to the street given in
addr:street.

I also wonder whether we need to include addr:terrace as an option,
now we have addr:substreet. To correctly format addresses, it's vital
for data consumers to know about the lowest street-level tags. I think
it might be better just to use addr:substreet for terraces, so that
data users have one fewer UK-specific tag to parse.

Also, I think addr:locality might be required on occasion. There can
be a named place/location in an address, which isn't a settlement, and
so can't be represented by addr:hamlet, addr:village, addr:town etc.
and isn't an addr:suburb either.

Finally, with regard to the address formatting algorithm, putting
addr:place after addr:parentstreet is going to be wrong for a lot of
places I've tagged. For example, I've used addr:place and
addr:parenetstreet respectively for industrial estates off a main
road, and also for named groups of cottages on a main road. (In both
cases, the new recommendation would be to use addr:substreet instead
of addr:place for theses.) Following the wiki, I took addr:place as an
alternative for addr:street. With this notion, addr:parentstreet
should logically come after addr:place in the address. I realise
others may have used addr:place in an addr:suburb type of context, but
I doubt many of those addresses will have an addr:parentstreet in
them. Hence putting addr:place between addr:street and
addr:patentstreet will probably result in fewer incorrect addresses.

Best wishes,

Robert.

PS: If/when this is agreed, it would probably be a good idea to try to
plan a re-tagging of the well-used but non-UK addr:state and
addr:province tags (over 10k instances each) to more appropriate UK
values. The only other "tag to avoid" with significant usage is
addr:district, but at least this does represent a UK concept. See
https://osm.mathmos.net/addresses/addr-tags.html

-- 
Robert Whittaker