Division hierarchy out of order for Kowloon (division in Hong Kong)

[tijptjik]

version 2025-10-22.0

Kowloon is a city (or area) within the Hong Kong SAR. One of the district in Kowloon is the 油尖旺區 Yau Tsim Mong District, but in the hierarchy, it's shown as if it was a parent division of Kowloon instead of (one of) its children:

{
  "id": "17009785-57fd-4e5b-af86-2d27352e4718",
  "country": "HK",
  "region": null,
  "subtype": "locality",
  "class": "city",
  "local_type": [
    {
      "key": "en",
      "value": "city"
    }
  ],
  "hierarchies": [
    [
      {
        "division_id": "fb68fc73-3ac6-41c9-a692-22fcf20cb5be",
        "subtype": "country",
        "name": "中国"
      },
      {
        "division_id": "b4f09a9f-4cba-4a7c-bf58-2e63bc2e913d",
        "subtype": "dependency",
        "name": "Hong Kong SAR"
      },
      {
        "division_id": "c8ca7da1-2688-402a-8eb9-199b69b5691c",
        "subtype": "region",
        "name": "油尖旺區 Yau Tsim Mong District"
      },
      {
        "division_id": "17009785-57fd-4e5b-af86-2d27352e4718",
        "subtype": "locality",
        "name": "九龍 Kowloon"
      }
    ]
  ],
  "parent_division_id": "c8ca7da1-2688-402a-8eb9-199b69b5691c",
  "theme": "divisions",
  "type": "division"
}

[krizleebear]

I've looked up the source data from OSM. You can find this in the attribute 'sources' for each division.

Yau Tsi Mong district = https://www.openstreetmap.org/relation/2670978 - which is AdminLevel 6
Kowloon = https://www.openstreetmap.org/node/6986131016 - which is a node/point on city level

So at first this looks like a 1:1 mapping from OSM data.
But if you look closer, it's not. Because the children division of Kowloon is missing.

Note that division dataset also has a suburb division 'Yau Tsim Mong' (see my code example).
And in this division, the hierarchy is complete.

My interpretation: Similar/same error like #441 and #235

I hope, we'll get some feedback soon :)

                  id = 4cabfde6-3c2a-40fe-8155-5dc59fa13959
            geometry = POINT (114.1665849 22.3118917)
                bbox = {'xmin': 114.16657, 'xmax': 114.16659, 'ymin': 22.311892, 'ymax': 22.311893}
             country = HK
             version = 2
             sources = [{'property': '', 'dataset': OpenStreetMap, 'license': ODbL-1.0, 'record_id': n13169032646@1, 'update_time': '2025-09-25T08:21:41Z', 'confidence': NULL, 'between': NULL}]
         cartography = NULL
             subtype = macrohood
               class = NULL
               names = {'primary': 油尖旺區 Yau Tsim Mong, 'common': {vi=Du Tiêm Vượng}, 'rules': NULL}
            wikidata = NULL
              region = NULL
        perspectives = NULL
          local_type = {en=suburb}
         hierarchies = [[{'division_id': fb68fc73-3ac6-41c9-a692-22fcf20cb5be, 'subtype': country, 'name': 中国}, {'division_id': b4f09a9f-4cba-4a7c-bf58-2e63bc2e913d, 'subtype': dependency, 'name': Hong Kong SAR}, {'division_id': c8ca7da1-2688-402a-8eb9-199b69b5691c, 'subtype': region, 'name': 油尖旺區 Yau Tsim Mong District}, {'division_id': 4cabfde6-3c2a-40fe-8155-5dc59fa13959, 'subtype': macrohood, 'name': 油尖旺區 Yau Tsim Mong}]]
  parent_division_id = c8ca7da1-2688-402a-8eb9-199b69b5691c
               norms = NULL
          population = NULL
capital_division_ids = NULL
capital_of_divisions = NULL
               theme = divisions
                type = division

Note: the source node for this division https://www.openstreetmap.org/node/13169032646 was deleted 14 days ago from OSM.

[tijptjik]

Thanks for the excellent sleuthing!

Yau Tsi Mong district = https://www.openstreetmap.org/relation/2670978 - which is AdminLevel 6
Kowloon = https://www.openstreetmap.org/node/6986131016 - which is a node/point on city level

So just for clarity, the Overture Hierarchy sources from the following OSM nodes/relations:

• China PRC - OSM:Admin Level 2
• Hong Kong SAR - OSM:Admin Level 3
• Yau Tsi Mong district - OSM:Admin Level 6
• Kowloon - OSM:City

The last item, the node, is used as the label of the Kowloon area (OSM:Admin Level 5), but should NOT appear as a child of the Admin Level 6 division it happens to be in.

The facts on the ground are that Hong Kong SAR has 18 districts (Yau Tsim Mong is one of them). Legally, these are districts of Hong Kong SAR (Admin Level 3 on OSM, subtype=dependency in overture). However, 5 district are wholly inside Kowloon (Admin Level 5 on OSM, subtype=locality in overture) which could allow Kowloon to be inserted into the hierarchy, but this would be an alternative hierarchy to the de jure administrative partitioning. Similarly, Hong Kong Island contains 4 districts, and the New Territories contain 9 districts.

For reference:

Suggestion : In the context of Hong Kong SAR, it would make the most sense for Hong Kong Island, Kowloon, and New Territories to be treated as subtype=region (or subtype=admin1 in the upcoming schema change) and the districts would be subtype=county (or subtype=admin2 in the new schema).

Constructing Hierarchies

From the docs :

[...] The default parent division is the parent division as seen from the default political perspective, if there is one, and is otherwise chosen somewhat arbitrarily. The hierarchies property can be used to inspect the exhaustive list of parent divisions.

Is the process by which hierarchies are constructed documented somewhere, or is the source code available?

Erroneous Nodes

Note that division dataset also has a suburb division 'Yau Tsim Mong' (see my code example).
And in this division, the hierarchy is complete.

This was recently, erroneously, added and has since been reverted.

Note: the source node for this division https://www.openstreetmap.org/node/13169032646 was deleted 14 days ago from OSM.

Yes - that was correct, someone erroneously added nodes with place=suburb for some districts, which was picked up by Overture and resulted in duplicate divisions / bogus hierarchies (from your example, Yau Tsim Mong == Yau Tsim Mong District, there's no meaningful distinction between them).

[tijptjik]

My interpretation: Similar/same error like #441 and #235

Indeed, it is similar:

• In your case (Berlin) the issue was that the locality of Berlin was treated as being in the locality of Mitte (it's a quarter right?) which in turn was in the region of Berlin.
• In this case, the locality of Kowloon is treated as being in the region of Yau Tsim Mong, which in turn is in the dependency of Hong Kong SAR.

The difference is that in Hong Kong there is an (optional) regional Admin 5 layer (Kowloon) which doubles as a "city", and it's not currently part of the hierachy for localities in the city. But it arguably should be.

A further difference is that if you looked at the other 2 divisions at that level, Hong Kong Island and New Territories, they wouldn't be considered 'cities' .. one is an island with several urban settlements, the latter is an area with several towns, islands, etc.