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

[Sarah Hoffmann]

Hi Tom,

On Sun, Jan 09, 2022 at 09:03:45PM +0000, Tom Crocker wrote:
> On Sun, 9 Jan 2022, 11:10 Sarah Hoffmann via Talk-GB, <
> talk-gb at openstreetmap.org> wrote:
> 
> >
> > Regarding the opposing proposals of addr:substreet (as currently in the
> > wiki) and addr:parentstreet (as proposed by Simon Poole and Tom
> > Crocker), they work both from a data user point of view as far as I can
> > see. Which one you go for depends on whether you put more emphasis on
> > the dependent street or the parent street in an address:
> >
> > Say you have an address like '4 Rose Terrace, Garden Street'. You can
> > tag this as:
> >
> > addr:housenumber=4
> > addr:substreet=Rose Terrace
> > addr:street=Garden Street
> 
> 
> Hi Sarah
> 
> Thanks very much for your contributions. Just to clarify, my understanding
> of the wiki page is that the combination of addr:substreet with
> addr:parentstreet is being proposed, rather than as above, to avoid the '4
> Garden Street' error. Perhaps Rob can confirm?

Yes, it looks like I have misread the wiki page. I assumed
addr:substreet is always to be used for a dependent throughfare but I
see now that addr:street is to be used when the dependent part is a
street.

That makes my previous point moot and I fully agree with you and Simon
then. addr:street/addr:place + addr:parentstreet will be 100% equivalent
to the wiki schema. It would also be preferable then because it would be a lot
easier to handle from the data user side. That is a simple question
of combinatorics. With 4 tags to consider there are 16
possibilities how the tags may be combined on a single address. Most of
them would be invalid according to the wiki page but that never has
stopped a mapper from using them anyway, so data users need to be
prepared. So why not use just 3 tags when the 8 combination they offer
are sufficient.

I also don't buy the argument that addr:place must be avoided because
of its heavy use as a addr:suburb replacement. Where
addr:place is being used in that way, it pretty much always appears
together with addr:street. This would still be an illegal combination
under the addr:parentstreet schema and as such be easily detectable.

Sarah