Re: [Talk-GB] boundary mania
On 2018-08-27 00:24, Mark Goodge wrote: > On 26/08/2018 21:36, Colin Smale wrote: On 2018-08-26 21:17, David Woolley > wrote: > > It looks to me as though boundaries can be defined recursively, so Hampshire, > rather than its bounding ways, ought to to be the object referenced in the > bigger entities. This wouldn't work in the case of civil parishes as > components of districts and UA's though. You cannot define a district as the > union of the parishes. There are unparished areas, detached parts and "lands > common" which complicate the model. However I believe every point in the UK > is within some district/UA, and every district is within a county, giving > 100% coverage at that level. Every point is within a district, but not every district is within a county - unless, that is, you consider a unitary authority to be effectively two different entities that happen to have identical boundaries. I think you understood what I meant. AIUI a UA is normally technically a district. A city is an orthogonal concept- a "city council" can be a UA (eg Nottingham), a District (eg Canterbury) or a Civil Parish (eg Salisbury) that has been awarded that status. And not every city has its own council of any type (eg Bath). And of course a council is not an area, it is an administrative body. There are admin areas defined in law that do not have a corresponding council, eg the county of Berkshire and many Civil Parishes. Sometimes they play games with the naming: Rutland County Council is not a county council, because there is no extant county of Rutland. It is a non-metropolitan district with unitary status, whose council is formally called Rutland County Council District Council. I stand by my comment that the "sum of parts" system could work down to the district/UA level, and not down to the civil parish level.___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] boundary mania
On 26/08/2018 21:36, Colin Smale wrote: On 2018-08-26 21:17, David Woolley wrote: It looks to me as though boundaries can be defined recursively, so Hampshire, rather than its bounding ways, ought to to be the object referenced in the bigger entities. This wouldn't work in the case of civil parishes as components of districts and UA's though. You cannot define a district as the union of the parishes. There are unparished areas, detached parts and "lands common" which complicate the model. However I believe every point in the UK is within some district/UA, and every district is within a county, giving 100% coverage at that level. Every point is within a district, but not every district is within a county - unless, that is, you consider a unitary authority to be effectively two different entities that happen to have identical boundaries. From a legal perspective, districts (or boroughs, cities and unitary authorities) are the fundamental building blocks of British local government. Parishes or communities, where they exist, are subdivisions of districts. Counties or metropolitan authorities, where they exist, are unions of districts. The district is the "principal authority" defined in legislation, everything else is relative to it. (As an aside, this is also one of the big drivers of nostalgia for the pre-1974 "historic" counties. The Victorian system had the county as the fundamental unit. So even where we still have counties, they are not the same as they used to be). Mark ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] boundary mania
On 2018-08-26 21:17, David Woolley wrote: > It looks to me as though boundaries can be defined recursively, so Hampshire, > rather than its bounding ways, ought to to be the object referenced in the > bigger entities. This wouldn't work in the case of civil parishes as components of districts and UA's though. You cannot define a district as the union of the parishes. There are unparished areas, detached parts and "lands common" which complicate the model. However I believe every point in the UK is within some district/UA, and every district is within a county, giving 100% coverage at that level.___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] boundary mania
On 26/08/2018 20:01, Frederik Ramm wrote: Hi, On 08/26/2018 12:46 PM, Colin Smale wrote: It has gone all quiet here, and in the mean time smb001 has been making steady progress across England. I think he shouldn't have done this. He should have argued his case here and the community should have come to an explicit resolution, rather than one party creating a "status quo". I agree. Personally, I am very much against mapping historic boundaries in OSM, mostly because the exemption from the "on the ground" rules that apply to current administrative borders (they are so important that we make an exception) don't hold for historic boundaries. And also because there is no single entity otherwise known as the "historic" boundaries. Even before the major changes in the 1970s (objection to which is what a lot of the passion for the historic boundaries stems from), they were not perfectly stable. The Victorians were inveterate tinkerers, they adjusted boundaries continually even if only at a much more local level than the 1974 reforms. Any mapped historic boundaries are, therefore, nothing more than a snapshot of what they were at a particular moment in time, not a record of how things have always been. Even the KML downloads provided by the Association of British Counties, the prime cheerleader for the historic counties, is offered in two different definitions which match different snapshots of the boundaries. The historic boundaries are useful for a number of historic research and educational uses. But they are only properly meaningful when used in the form which matches the date being researched. Unless we are going to have every variant of the historic boundaries mapped on OSM (in which case, we should also map newer but now defunct administrative boundaries, such as the county of Avon), there's no real value in mapping them in OSM at all. Leave them to dedicated historic projects where the data is relevant. Mark ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] boundary mania
On 26/08/18 20:01, Frederik Ramm wrote: I think we should all think twice before duplicating and triplicating data in OSM just because there's yet another boundary that includes Hampshire. We should find a way to reference existing boundaries instead of copying them. It looks to me as though boundaries can be defined recursively, so Hampshire, rather than its bounding ways, ought to to be the object referenced in the bigger entities. On the original question, I would say that the thin end of the wedge is going in and needs to be stopped. ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] boundary mania (was: 'historic' county boundaries added to the database)
Hi,
On 08/26/2018 12:46 PM, Colin Smale wrote:
> It has gone all quiet here, and in the mean time smb001 has been making
> steady progress across England.
I think he shouldn't have done this. He should have argued his case here
and the community should have come to an explicit resolution, rather
than one party creating a "status quo".
Personally, I am very much against mapping historic boundaries in OSM,
mostly because the exemption from the "on the ground" rules that apply
to current administrative borders (they are so important that we make an
exception) don't hold for historic boundaries.
But there's a general problem with boundary relations getting out of
hand. Take this little unnamed waterway here
https://www.openstreetmap.org/way/614127384
which is meanwhile a member of 19 different boundary relations:
* South East England European Parliamant Constituency
* The admin_level=8 boundaries New Forest and East Dorset
* New Forest West UK Parliament Constituency (4152802)
* Alderholt Civil Parish and Damerham Civil Parish
* Cranborne Chase & West Wiltshire Downs AONB (2664452)
* Dorset historic county and Wiltshire historic county
* an administrative region called "South West England" and an
administrative region called "South East England", both admin_level 5
* The Hampshire Constabulary boundary ("boundary=police") which exists
twice (relations 3999378, 8188274) if any proof was needed that this is
getting out of hand even for those who added it
* The Hampshire Fire and Rescue Service boundary ("boundary=fire")
* Hampshire County and Dorset County
* Hampshire Ceremonial County and Dorset Ceremonial County
* A statistical boundary called "Hampshire and Isle of Wight"
I have not analyzed these in detail and I won't make an attempt to tell
the readers of this mailing list which of these make sense to have in
your country. But I have a hunch that, say, the statistical boundary
"Hampshire and Isle of Wight" is not actually defined as a boundary. I
have a hunch that if the boundary of Hampshire were to change, then this
statistical area would also change - because it is *not* defined by
geometry, but just by reference to existing administrative boundaries.
I think we should all think twice before duplicating and triplicating
data in OSM just because there's yet another boundary that includes
Hampshire. We should find a way to reference existing boundaries instead
of copying them.
Practically all of the relations above have version numbers in the
hundreds, version numbers that have again increased when smb1001 did his
historic boundary mapping - of course he hasn't changed anything in the
statistical boundary "Hampshire and Isle of Wight" but still he's listed
as last modifier of this relation just because he has just split up a
way that was part of the Hampshire boundary.
I think if we continue heaping ever more boundary relations onto what we
have, we'll make things less and less understandable, less and less
maintainable.
But that's a general remark, not *specificall* aimed at history county
boundaries.
Bye
Frederik
PS: Of course, public transport relations are an even bigger culprit.
There are a handful of ways in OSM in England that are member of more
then 100 relations, mostly bus routes as far as I can see.
--
Frederik Ramm ## eMail frede...@remote.org ## N49°00'09" E008°23'33"
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