It might be good to look at how My Society's MapIt api handles the levels.
I had to use that very quickly and then found myself writing lots of edge
queries to get the right level in the heirachy.
On 20 Feb 2014 19:53, Colin Smale colin.sm...@xs4all.nl wrote:
Hi Robert,
On 2014-02-20 20:17, Robert Whittaker (OSM lists) wrote:
On 20 February 2014 11:34, Colin Smale colin.sm...@xs4all.nl wrote:
one thing I noticed is that there are two schools of thought regarding
Metropolitan Districts. These are a subdivision of Metropolitan Counties,
of which there are six: Greater Manchester, Merseyside, South Yorkshire,
Tyne and Wear, West Midlands and West Yorkshire.
I would like to normalise this tagging, and looking at the current usage
above and the wiki[1], propose that the Metropolitan Counties become
boundary=ceremonial, and the Metropolitan Districts become
boundary=administrative, admin_level=8.
If the Metropolitan Districts have essentially the same
administrative powers/functions as a unitary authority, then I think
they should be tagged with the same admin_level (i.e. 6) to reflect
that fact. We'd then be consistently using admin_level=6 for the
highest tier of local government. If they are slighty different (i.e.
some powers rest elsewhere) then maybe we could consider using
admin_level=7 instead. As far as I can tell, they're definitely not
similar to the district councils under a normal county council, so iI
think it would be better to avoid using admin_level=8.
Sounds reasonable to me. They are missing various powers of a true UA,
which are organised at a Metropolitan County level in joint boards. So
admin_level=7 would reflect that intermediate level.
Ceremonial counties are a completely separate division of the country into
Lord Lieutenancy areas -- see
http://en.wikipedia.org/wiki/Ceremonial_counties_of_England . So in OSM
I'd expect to find these in existence over the whole country, not just for
the Metropolitan Counties. Since they have no administrative
local-government function, I wouldn't expect them to need or have an
admin_level tag. Sometimes they'll be coterminous with a normal county
(i.e. the area controlled by a County Council). In which case, I'd expect
to see two different relations in OSM, one for each entity.
That is how lieutenancies/ceremonial counties are currently tagged -
boundary=ceremonial, no admin_level. Indeed, if coterminous with an
administrative county, then two relations are needed. I believe many
already exist like this. See:
http://wiki.openstreetmap.org/wiki/English_Counties (which I have tried
to keep up-to-date) for an overview. It looks like there are still a few
missing - I will work on that.
To further complicate things, it seems that in a relatively recent
development, there is now a Greater Manchester Statutory City Region with
a Greater Manchester Combined Authority that does have some significant
administrative functions. See
http://en.wikipedia.org/wiki/Greater_Manchester_Statutory_City_Region .
This region is coterminous with the Greater Manchester Ceremonial County,
but is a different entity. As above, I'd expect the two identical
boundaries to have separate OSM relations. One with boundary=ceremonial and
no admin_level tag, and the other with boundary=administrative and an
appropriate admin_level. The admin_level value needs to be greater than 5
(English Regions) and less than the value we've used for the individual
borough/city areas. So presumably we wouldn't be able to use admin_level=6
for the Metropolitan Districts within Greater Manchester, so 6 can be
used by the Combined Authority.
Hmm, I didn't realise that... Wikipedia suggests it may be modelled on the
Greater London Authority, which limited, well-defined powers. There doesn't
seem to be a relation for the GLA - but there is one (65606) at
admin_level=6 called London.
Whether we should use 7 rather than 8 for the Metropolitan Districts
would, I think, depend on how much their powers/responsibility are similar
to a normal districts within a normal county, and how much they retain more
of the character of a Unitary Authority or other Metropolitan Districts.
Robert.
Colin
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