Override IDs ?

[etienneJr]

Hi Richard,
Is it possible to override the ID of an osm element when it is added on a layer? For example on an admin_center node, to put the ID of its parent boundary relation (a much more interesting element for the user on a clickable map) rather than its own ID?
Thanks!

[oberhamsi]

i don't think that's possible right now.

i think you are looking for something opposite to what, for example, LayerAsCentroid provides:

if you're processing a multipolygon-type relation (e.g. a boundary) and it has a "label" node member, then by adding "label" as an argument here, this will be used in preference to the calculated point.

this looks at the "child" node and you want to look at the parent.

[etienneJr]

You are right, LayerAsCentroid is perfect for boundary and other multipolygon relations with a label node. But it won't work for example for waterway relations. When adding a waterway=river way in the tile, I want it to get the ID if its parent type=waterway relation.

[systemed]

It's not currently possible, but after a quick scan of the code it looks like it might be patchable. I think you'd need to create a new method in osm_lua_processing.cpp to set originalOsmId. Something like this:

void OsmLuaProcessing::rawModifyId(const int newId) {
    originalOsmId = static_cast<int64_t>(newId);
}

and add luaState["ModifyID"] = &rawModifyId; to the constructor around line 250 with all the similar statements. I haven't tried this but do have a go and let me know if it works.

[etienneJr]

Thank you for these advice! I will test it and keep you informed of the results.

[etienneJr]

That was perfect advice, I pushed #866, thanks !