[Tagging] Feature Proposal - RFC - addr:interpolation on closed ways and nodes

[Sarah Hoffmann]

On Mon, Dec 21, 2020 at 02:37:08PM +0100, ipswichmapper--- via Tagging wrote:
> https://wiki.openstreetmap.org/wiki/Proposed_features/addr:interpolation_on_closed_ways_and_nodes
> 
> Quick proposal I just created to accept this form of tagging. This follows from a discussion on the Talk-GB mailing list.
> 
> https://lists.openstreetmap.org/pipermail/talk-gb/2020-December/025553.html
> 
> 
> Please comment if there are issues with accepting this form of tagging.

I dislike this kind of tagging to the point that I've refused to
support it in Nominatim in the past. See
https://github.com/osm-search/Nominatim/issues/565 for the full disucssion.

The problem is that it makes the interpretation of addr:housenumber and
addr:interpolation dependent on the presence of another tag.

Note that addr:housenumber=40-48 can be a valid housenumber. Example:
https://www.openstreetmap.org/way/285077586 So to know if the tag needs
to be interpreted as a single housenumber or as a housenumber range
you need to check if the node/way has a addr:interpolation tag in addtion
to the addr:housenumber tag.

Similarly, a way with addr:interpolation needs to be processed in two
different ways: If a addr:housenumber is present, then assume it's a
building and parse the addr:housenumber tag to get the range. If no
housenumber is on the way, assume it is a good old interpolation line
and look at the housenumbers along the nodes of the way.

I find this kind of double meaning for tagging confusing and error-prone.
But I might be fighting wind mills here.

Sarah