[Talk-GB] UK street addressing

ndrw ndrw6 at redhazel.co.uk
Sun Dec 20 19:05:48 UTC 2020

On 20/12/2020 16:09, Chris Hill wrote
> Using the two separate towns is not correct. The house (or whatever) 
> is not in Largertown,it is in Smalltown.

By convention addr:* tags are for addressing, not for mapping 
administrative boundaries. For the latter we can use is_in tags, 
although explicit admin boundaries are preferable.

> Postal towns are in invention of Royal Mail. Correct addressing of any 
> location are set by Local Authorities, not Royal Mail. There are no 
> postal towns in LA addresses.

It is unfortunate Royal Mail is setting address information in such an 
arbitrary manner and that the resulting database is largely proprietary. 
But this is still the only addressing system we can use.

> In the original example the 'Smalltown' (or indeed village or even 
> hamlet) translates into addr:city in OSM. I know this may look 
> confusing as a small villiage is not a city, but that is, IMHO, the 
> correct way tobuild an OSM UK address.
> Adding postal towns is not only redundant, but is misleading. It looks 
> as though the way to find Smalltown would be first to go to 
> Largertown, when that is very rarely the case. OSM addresses are 
> hierarchical, RM addressing is not as postal town is usually a 
> separate place.

It is common to have country specific addr:* tags but where possible we 
should strive to follow OSM tagging conventions, and addr:city is 
defined a town/village associated with the postcode.

> I should have added that postcodes are a useful addition and my 
> postcode overlays can help to workout what the correct postcode is for 
> a given building. You can see more at https://codepoint.raggedred.net/

Yes, I am well aware of your overlays and have used them extensively in 
the past to map postcodes in East Anglia and several other areas. Thank 
you for providing and maintaining them.

A couple of years ago I've proposed a semi-automatic way of importing 
Code-Point Open postcodes to buildings, where building outlines are 
already available. As it is an imperfect solution the proposal has 
turned out rather unpopular. I still think having postcodes in the 
database far outweighs any inaccuracies that could arise, which in 
almost all cases are caused by buildings with multiple postcodes.


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