Tilemaker: include_ids and OSM ID

Question

I'm currently using tilemaker https://github.com/systemed/tilemaker/blob/master/docs/CONFIGURATION.md to generate mbtiles from osm pbf files.

I'm setting, in the config file, the parameter include_ids to true to generate in each mbtiles object (node or way) the original osm ID.

"settings": {
        "include_ids": true,
        ...
        }

What I don't understand so far is that the ID which is generated by Tilemaker is actually not the original OSM ID, that I can fetch via obj:Id()

Is there any reason why tilemaker ID generated via the 'include_ids = true` is actually not the expected osm id from the initial source ?

I'm using queryRenderedFeatures from maplibre to verify the content of my mbtiles, and for instance I have

[
  {
    "type": "Feature",
    "properties": {
      "osm_id": "4349756002",
      "name:latin": "Gilgamesch",
    },
    "id": 1103861383778,
    "layer": {
      "id": "poi",
      "type": "symbol",
      "source": "openmaptiles",
      "source-layer": "poi",
      "metadata": {},
      "minzoom": 15.5,
      "layout": {
        "text-font": [

where "osm_id": "4349756002" is the real node id from OSM (that I'm manually getting from obj:Id() from the pbf) and "id": 1103861383778 is the one generated by tilemaker. I can confirm that the expected osm id is https://nominatim.openstreetmap.org/ui/details.html?osmtype=N&osmid=4349756002

Anyone able to shed a light on what I'm doing wrong? Curious if there is mask to apply to go from 1103861383778 to `4349756002``

Answer 1

Lowest 40 bits of feature.id is real OSM id, and the rest encodes type of object: 1=node, 2=way, 3=relation. See include/output_object.h in TileMaker source. So:

osmId = feature.id & 0xffffffffff;
osmType = feature.id >>> 40;