[Talk-GB] Are Northern Ireland, Wales & England 'states'?

[Dave F]

This is a reply to a Q. I posed on Talk. Nominatum clearly prefer 
boundaries to is_in & say it's not heavy processing:
https://lists.openstreetmap.org/pipermail/talk/2016-August/076596.html

As UK boundaries are sure be updated in OSM, keeping the secondary is_in 
'cleanly managed' will be a major task.

On 22/08/2017 09:38, Lester Caine wrote:
> On 12/08/17 13:12, Dave F wrote:
>> I also think the 'is_in:country_code' along with all 'is-_in' tags are
>> redundant if there's a boundary tag..
> In the past I thought that the is_in element was something of a problem,
> but it does have a place when one remembers that OSM is all about the
> data. "if there's a boundary tag" is the problem here if one is
> extracting a set of data? Processing a number of boundaries around a set
> of objects takes time, while cleanly managed is_in:admin_area with a
> proper hierarchy allows a much quicker lookup of information such as -
> in the case of the the UK - parliamentary boundaries, wards, historic
> county, NHS admin area and so on without having to physically draw every
> fine detail of these ever changing boundaries. BUT it only works well if
> there is a well defined hierarchy so tagging is_in:gb-ward
> http://geoportal.statistics.gov.uk/datasets/417e93f21c5c419283ac23abc8eedcce_0
> gives all this data in a format we can freely use as with the other
> 'boundary' data.
>
> It is just a pity that 'postcode' is so badly organised that it quite
> regularly straddles these other boundaries, but is_in:gb-postcode would
> remove the need to add all of the associated address data to every
> object on a particular street, and for the vast majority of postcodes it
> WOULD also identify all of the other is_in: data at a higher level. It
> just needs an object defining is:gb-postcode and is:gb-ward to provide
> all the hierarchy ... without overloading the server with searches for
> all of the boundaries intersecting the original dataset?
>
> Of cause I am also still looking to maintain access to historic data,
> and this model makes it easy to check start and end dates of
> is:gb-postcode and is:gb-ward without having to maintain all of those
> boundaries actually in the base dataset - something which the majority
> of users seems to have decided against :(
>