Thanks, Brian. Answers below:
None of these are part of the CCC discussion with the exception of the “city” of Honolulu, which is currently represented as a node in OSM. I personally am indifferent as to the fate of the node itself, but this discussion would not result in a “city” boundary for Honolulu when a municipality does not even nominally exist.
Virginia’s 38x independent cities; Baltimore, Maryland; St. Louis, Missouri; and Carson City, Nevada, are all already coded as admin_level=6 without any corresponding county, as they should be.
It doesn’t really matter too much how the wiki evolved to where it is and what editing disputes have happened in the past. Picking out statements from the wiki as if they’re some kind of legal foundation won’t get you very far. Anyone can edit the wiki and there’s all sorts of things that are wrong or don’t reflect community consensus. The only thing that matters is correctly documenting what the most current community zeitgeist is.
That’s a fair point about the wiki – and perhaps I’ve overstated its importance for this particular discussion. However I’m hopeful the wiki will get to (and be maintained) where it would reflect current community consensus and I’m assuming the statement currently there did at the time it was made, or at least indicates there’s not been much consideration of what the community consensus is on the particular topic of CCCs since it has gone unchallenged for so long.
For consolidated municipal / county entities – are these really two separate entities with co-extensive boundaries, or are they a single entity that performs the role of both municipality and county? Are separate municipal offices, organizations, and political or popular identities maintained?
I’m not an expert in CCCs so I can’t answer everything here, but as for if “are these really two separate entities with co-extensive boundaries”, I can say – it depends . . .
At least 15 CCCs do not have coextensive boundaries. For example, Athens / Clarke County in Georgia is a CCC, but the boundary of Athens is smaller and within Clarke County, and Clarke County has another municipality, Winterville, located inside it.
Those 15 without coextensive boundaries would need (and currently do have) separate entities in OSM regardless of whether their governmental functions are combined.
And at least 17 CCCs are coextensive, of which 13 currently have the county and the city in OSM, and all of which have previously had both the county and city in OSM.
I might also add that of those 13, some are non-trivial, such as the five counties / boroughs of New York City, Philadelphia / Philadelphia County, New Orleans / Orleans Parish, Indianapolis / Marion County, etc.
Note that the 15 non-coextensive CCCs and the 17 coextensive CCCs do not include Alaska and four that I cannot verify whether they are coextensive or not.
Also, my list CCCs comes from the Consolidated city-county - Wikipedia list and Wikidata entities. I maintain there is a Philadelpha County, I’m sure recognized by the state of Pennsylvania as a county, as distinct from the city of Philadelphia, even though their government functions are consolidated and boundaries coextensive.
How does this impact data consumers that currently expect these cases to be one entity? Will the change cause data consumers currently using the
admin_level=6boundaries to encounter duplication when new, overlappingadmin_level=8boundaries are introduced to the map? Have you explored the impact on known data consumers?
I admit I haven’t explored that and wasn’t aware such a wonderful resource even existed. I’d have to take time to look or rely on someone more familar with it to help me, however @stevea states “I’m listening to downstream user concerns and I see no (or few) contradictions”, which I’m assuming answers this portion.
Does the duplication support all use cases well or is the proposed change tailored to support one specific use case?
This is not an approach tailored specifically to me. Getting a list of counties and also getting a list of cities, even if their administrative functions are combined and even if their boundaries are coextensive would be a common exercise for any data consumer interested in that level of administrative boundary.
I actually believe it supports all use cases even better than what the current status does, the current status being that four counties are missing from OSM’s data. Of course I’m speaking for other data consumers, but currently they have to address either the 4 missing county entries or the 13 with entries that also have coextensive cities.
Here’s an example using San Francisco and Philadelphia, both similar sized, major CCCs that have coextensive boundaries, one of which has both the county and city in OSM and the other of which does not.
This Overpass query should result in a list of the 58 counties in California: List of counties in California - Wikipedia
[out:json];
area[wikidata=Q99]->.a; // Q99 = California
relation[admin_level=6](area.a);
out tags;
It does return 58 rows, one being the CCC of San Francisco.
A user might use query to return all cities in California:
[out:json];
area[wikidata=Q99]->.a; // Q99 = California
relation[admin_level=8](area.a);
out tags;
It returns 594 rows but San Francisco is missing, although someone might reasonably think San Francisco should show up on the list of admin_level=8 cities in California.
Turning to Pennsylvania, there are 67 counties: List of counties in Pennsylvania - Wikipedia
[out:json];
area[wikidata=Q1400]->.a; // Q1400= Pennsylvania
relation[admin_level=6](area.a);
out tags;
It does return 67 rows, one being the CCC of Philadelphia County.
But a user might also reasonably think this query will return all cities:
[out:json];
area[wikidata=Q1400]->.a; // Q1400 = Pennsylvania
relation[admin_level=8](area.a);
out tags;
It returns 2262 rows and the CCC of Philadelphia is present as someone might expect from a list of admin_level=8 cities in Pennsylvania.
There is no different between San Francisco / San Francisco County and Philadelphia / Philadelphia County other than three years ago someone seemingly arbitrarily deleted San Francisco County and I’m just asking for the four missing counties to be put back into OSM as they were previously and the tagging updated to mirror the other 13 CCCs with coextensive boundaries.
If a data consumer wishes to treat consolidated entities as consolidated objects, is there sufficient tagging so that they can de-duplicate these boundaries?
Not if tagged as normal counties and cities, however we could possibility use a tag that highlights not only that they are CCCs, but coextensive CCCs if appliable (since not all CCCs are coextensive). Of a data consumer wanted to treat them as consolidated objects then they could.
Alternatively I suppose they could check the boundaries themselves, but I suspect the tag would be more much efficient and welcomed by the data consumer.
Which entity should maintain the history of the original boundary? OSM IDs are semi-stable, so we should not cause unexpected behavior by changing what a boundary relation represents.
The relations for San Francisco County, Nantucket County, Denver County, and Broomfield County are already in the OSM database, just deleted. They just need to be reverted and the tags cleaned up.
The relations for San Francisco County and Nantucket County are the ones from years ago. I couldn’t revert the deletions of Denver County and Broomfield County so I created new ones.
Bottom line – there are 17 CCCs with coextensive county and city boundaries, and it would be beneficial to all data consumers, current and future, for them to be entered into OSM consistently, but they are not.
At present four have only the city at admin_level=6, the same as an independent city (which they are not), while 13 have both the city and the county entry at admin_level=8 and admin_level=6 respectively, the same as the other 15 CCCs that do not have coextensive boundaries.
To make the 17 CCCs with coextensive boundaries the same, we should either:
- reinstate the four counties that are not present, or
- delete the 13 counties that are present
Option 1 would also have the added benefit that all CCCs would treated the same regardless of having coextensive boundaries or not and will match Wikidata and Wikipedia.
Either way, from there data consumers can adjust since they know San Francisco / San Francisco County will be treated the same as Philadelphia / Philadelphia County.
Once we figure this portion out perhaps the discussion on tagging can follow.