In the US, should all relations with boundary=administrative have a label node?
What about an admin_centre node?
Is it dependent on the admin_level of the boundary?
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admin_centre should only be used for capitals. So, state capitals to a state boundary, county seats for a country boundary, etc.
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An admin_centre node is only for indicating the capital city of an admin boundary, and thus should only be present for boundaries that have a capital city. A state boundary would have an admin_centre node for the state capital. A municipal boundary would not, because there is not some other entity within a municipality that is the capital city of it. Some mappers will assign the admin_centre role to the city or town hall building of a municipality. This is incorrect and should be removed when found.
Ideally label nodes should be optional because data consumers should be able to calculate label positions from polygons. However, there are a number of data consumers that donât do this (OpenMapTiles for example) and instead rely entirely on label nodes. Regardless, label nodes can be useful for oddly shaped polygons where a calculated centroid would end up in an unexpected place.
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The label role also helps Nominatim know that a boundary and a place node are the same thing.
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Ohh, I was prodded by one of the QA tools to do this. Iâll have to fix it when everything is back up.
On a similar note should a municipality have both a border and a node? That was the situation when I started working on the town.
Indeed. I should have clarified that it is the label nodes for counties, states, and nations that would ideally be optional. A city or town can generally be well represented by a node near the downtown commercial/cultural center. For larger territories, the exact position of a label node ends up being much more arbitrary.
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How did that get decided? If youâre gonna put it in Kansas, at least put it in Lebanon.
This is an educated guess, but âout in the Kansas sticksâ (Styx?) happened from a purely-mathematical centroid calculation. (Of two-dimensional area on the surface of a sphere, notwithstanding our planetâs odd pear-shaped geodesy).
In Michigan, I include the admin_centre below the state level for admin_level=6 (counties) and admin_level=7 (townships) - using the administrative building address node- that way you know exactly where to go to find the person(s) in charge!
Same for National Forests and Ranger Districts- tag the forest headquarters or ranger station amenity/address node so you know where to go to get permits, maps, etc.!
Hmm. admin_centre is supposed to indicate the presence and general location of a capital city, not the specific location of a headquarters building. Using it for the latter purpose skunks the meaning since then it canât be relied upon to indicate the former. A county certainly can have a capital city (Tagging county seats on boundary relations versus place points), but Iâve not heard of a township, national forest, or ranger district having one. If including the headquarters building as a role in a boundary relation is important (some may disagree on this), then I would encourage a different role for this purpose so as not to skunk the meaning of admin_centre.
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Function over form- why tag a meaningless and arbitrary city node when you can use an address node where you can actually find the administrator of the administrative area, along with opening hours, phone number, website, email? Can I please speak to the person in charge?
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Speaking! How may we be of service? 
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For what itâs worth, the label node for a populated place is for situations where a data consumer canât show the boundary in detail, such as when a rendered map is zoomed out. Marking a point at the geographic centroid of the boundary would often be misleading and arbitrary, but most places have a traditional center that canât be derived automatically, such as the intersection at the origin of the numbered street grid, or the main town square, or indeed the city hall.
To be sure, you should map a cityâs administrative building and tag it with contact information such as an address and phone number. Thereâs no need to add it to the boundary relation, because the amenity=townhall tag tells data consumers that itâs the cityâs headquarters. The name=*, operator=*, and operator:wikidata=* tags can also clarify the governmentâs jurisdiction.
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(âRerunâ from 2023)
A bit off-topic, Happy Holidays , with this entry from our admin_level=4 entry in USAâs row:
(To the tune of The 12 Days of Christmas, the second line of which is âFive Golden Ringsâ):
âAt the fourth admin level, the USA gives us:
THE FIF-TY STATES!
3 Territories,
2 Commonwealths
and the District of Col-um-bi-a-ah.â
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But amenity=townhall doesnât work for National Forest administrative boundary relations, and when I say person in charge I mean the person in charge of the administrative area.
I am not talking about the Label role for nodes, only the admin_centre role. And wikidata etc doesnât dial up well from within the map- having an amenity=townhall, amentity=ranger_station node as admin_centre within other administrative boundary relations below admin_level=4 makes perfect sense and is an example of the creativity and innovation we seek to facilitate within OSM, not arbitrary and authoritative rules that styme innovation and participation. Search via the OSM nomination for the name of the township or national forest, even a state forest- and the relation that is displayed already includes the node for the admin_centre, making it easy to locate and include in map-making for that feature in one tidy package. Some arbitrary limit of not utilizing that relation member role below a certain admin level does not seem to fit within OSMâs mapper-driven, community-building ethos but instead to come from rigid institutional thinking we all have had enough of, and brought us to the OSM community.
And this is why I donât partcipate much in the OSM community and dialoge because everything becomes a debate and one must go on the defensive right away. Instead, I just map and have made a tremendous difference in my home state over the past two years.
Tags have meaning, and data consumers have come to expect those meanings to be consistent across the database. When that consistency is broken, unexpected things happen across an ecosystem of apps and services that use this data. Making up your own meaning because you think it makes more sense just causes tags to get â if youâll forgive the phrase â skunked!
This is a community endeavor, and âmy way or the highwayâ attitudes towards how things should be mapped are unproductive.
Thank you for mapping, of course. However, if you map things in ways that the community regards as an error, it will be undone by the next mapper that comes along and encounters it.
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There isnât an arbitrary limit. I think thereâs a misunderstanding about the meaning of this role. admin_centre is just a confusingly named role thatâs supposed to indicate the capital city of the jurisdiction represented by the boundary relation. âAdministrative centerâ is the generic term in English for what weâd call a national capital, state capital, or county seat in the U.S.
If we were to apply this role to government headquarters instead, then the admin_centre of the U.S. would be the Capitol Building or the White House, and the admin_centre of Michigan would be the statehouse or governorâs mansion. Should a political map of the U.S. really label ââ
Michigan State Capitolâ as the state capital instead of ââ
Lansingâ?
That said, admin_centre might not even be essential on a county or state boundary relation, since thereâs a competing capital=* tagging scheme that isnât as frequently confused with the label role. OpenHistoricalMap generally doesnât use the admin_centre role on the boundary of anything, and things seem to be holding up OK.
OK, I thought you were talking about cities. The practical use case for tying a city hall to its city is a little less clear, since people donât go straight to the town hall when they visit a town; the visitor center might be a more likely destination. I could see how a ranger station would be a more natural destination for a national forest or nature preserve, though itâs less clear to me that this is a property of a boundary per se.
Iâve sometimes wanted to express something similar when mapping a large college campus. After all, the college has a main address and phone number, but it feels weird and unhelpful to tag this information directly on the whole campus without saying exactly where the address and phone line are located. admin_centre isnât an obvious option because the campus isnât modeled as a boundary relation.
Whenever this happens, you can create a site relation that has the main feature as the perimeter member and the head office as the admin_centre member (though maybe it should be called something else to avoid the confusion above). Site relations have been around for a long time, but theyâre still pretty experimental, sort of a catch-all for when more rigidly defined relation types prove inadequate.
Stanford University has a site relation partly because itâs large enough to encompass multiple ZIP codes, making the contact information on the amenity=university area especially awkward. San JosĂ© State University includes several entrance and parking members, which would theoretically help routers send users to the most relevant part of campus when searching for directions.
Perhaps you could try using a site relation to explicitly tie the national forest boundary to the ranger station. While youâre at it, you could add any named entrances to the relation to improve routability. This kind of mapping is still quite rare but would enjoy more widespread software support once thereâs a critical mass of coverage.
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Replace amenity=townhall with whatever feature type you are trying to find inside a particular area. Hereâs amenity=ranger_station in Monongahela National Forest. The features donât need to be part of the boundary relation object to be findable, just geographically within it.
Itâs really not that innovative, just a shortcut to avoid having to do a spatial query. Imagine using the same shortcut for a townâs court house, police station, fire station, library, school, hospital, and more. Pretty soon boundary relations would be huge pain to work with and nobody would want to touch them.
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Thanks to all who participate in this instructive topic and the strengthening-of-understanding it provides. There is both consensus and lesson curriculum here; an excellent learning space.