Clarification on osm_value

[renatolond]

Hi!

I've been trying kamoot for some queries and I got a question about the osm_value field.

I initially thought it corresponded to addresstype on nominatim. For instance, a query for "Schaerbeek" on Photon brings back:

{
  "features": [
    {
      "geometry": {
        "coordinates": [
          4.3737121,
          50.8676041
        ],
        "type": "Point"
      },
      "type": "Feature",
      "properties": {
        "osm_type": "R",
        "osm_id": 58260,
        "extent": [
          4.3571835,
          50.8811977,
          4.4130849,
          50.8434069
        ],
        "country": "Belgium",
        "osm_key": "place",
        "countrycode": "BE",
        "osm_value": "town",
        "name": "Schaerbeek - Schaarbeek",
        "county": "Brussels-Capital",
        "state": "Brussels-Capital",
        "type": "city"
      }
    }
  ],
  "type": "FeatureCollection"
}

While on nominatim it will bring

[
  {
    "place_id": 96162592,
    "licence": "Data © OpenStreetMap contributors, ODbL 1.0. http://osm.org/copyright",
    "osm_type": "relation",
    "osm_id": 58260,
    "lat": "50.8676041",
    "lon": "4.3737121",
    "category": "boundary",
    "type": "administrative",
    "place_rank": 14,
    "importance": 0.5585618242060414,
    "addresstype": "town",
    "name": "Schaerbeek - Schaarbeek",
    "display_name": "Schaerbeek - Schaarbeek, Brussel-Hoofdstad - Bruxelles-Capitale, Région de Bruxelles-Capitale - Brussels Hoofdstedelijk Gewest, België / Belgique / Belgien",
    "address": {
      "town": "Schaerbeek - Schaarbeek",
      "county": "Brussel-Hoofdstad - Bruxelles-Capitale",
      "region": "Région de Bruxelles-Capitale - Brussels Hoofdstedelijk Gewest",
      "ISO3166-2-lvl4": "BE-BRU",
      "country": "België / Belgique / Belgien",
      "country_code": "be"
    },
    "boundingbox": [
      "50.8434069",
      "50.8811977",
      "4.3571835",
      "4.4130849"
    ]
  }
]

osm_value in this case is town, same as addresstype.

However, if I look for Meierijstad, in photon:

{
  "features": [
    {
      "geometry": {
        "coordinates": [
          5.516390104700668,
          51.58844725
        ],
        "type": "Point"
      },
      "type": "Feature",
      "properties": {
        "osm_type": "R",
        "osm_id": 6838008,
        "extent": [
          5.3709476,
          51.6557026,
          5.6565559,
          51.5212962
        ],
        "country": "Netherlands",
        "osm_key": "boundary",
        "countrycode": "NL",
        "osm_value": "administrative",
        "name": "Meierijstad",
        "state": "North Brabant",
        "type": "city"
      }
    }
  ],
  "type": "FeatureCollection"
}

And in Nominatim:

[
  {
    "place_id": 100704797,
    "licence": "Data © OpenStreetMap contributors, ODbL 1.0. http://osm.org/copyright",
    "osm_type": "relation",
    "osm_id": 6838008,
    "lat": "51.58844725",
    "lon": "5.516390104700668",
    "category": "boundary",
    "type": "administrative",
    "place_rank": 14,
    "importance": 0.4566593489750686,
    "addresstype": "municipality",
    "name": "Meierijstad",
    "display_name": "Meierijstad, Noord-Brabant, Nederland",
    "address": {
      "municipality": "Meierijstad",
      "state": "Noord-Brabant",
      "ISO3166-2-lvl4": "NL-NB",
      "country": "Nederland",
      "country_code": "nl"
    },
    "boundingbox": [
      "51.5212962",
      "51.6557026",
      "5.3709476",
      "5.6565559"
    ]
  }
]

In this case, osm_value is administrative, osm_key is also different, but I cannot understand why.

Not that I'm using the following query params for photon layer=state&layer=county&layer=city&layer=district&limit=5&lang=en and the following for nominatim: featureType=settlement&format=jsonv2&language=en&layer=address&limit=10&addressdetails=1

Is this expected? I tried a few different layers and they seem to correspond to what I expected (towns, hamlets, etc), but this seems to be the case for municipality.

[lonvia]

osm_value corresponds to the type field in a Nominatim json response. Just as osm_key corresponds to the category (or class) field.

Photon's type field somewhat corresponds to Nominatim's addresstype field. It just doesn't have exactly the same categories.

[renatolond]

That's why the cases I pointed confuse me, if osm_value corresponds to type, then shouldn't the Schaerbeek example also have administrative as the osm_value?

[lonvia]

photon.komoot.io and nominatim.openstreetmap.org don't have exactly the same databases, they run slightly different software versions and are in different states of consuming minutely updates. OSM data changes all the time. If you get a boundary=administrative or a place=town depends on whether Nominatim managed to link the boundary relation and the corresponding place node.