Importing and updating only a sub-region

[navigatrum]

What is the proper way to import only one administrative sub-region contained in a OSM extract file?

I'm performing this task with Osmconvert:

1. downloading the smallest super-region of my adminitrative sub-region from Geofabrik
2. downloading the .poly file of my administrative sub-region from https://polygons.openstreetmap.fr
3. clipping my sub-region with osmconvert:
   osmconvert super-region.osm.pbf -B="sub-region.poly" -o=sub-region.osm.pbf
4. passing sub-region.osm.pbf to Nominatim.

Which works fine, but with a such workflow I can't use Nominatim's auto-update features.

So I'm wondering if there is an alternative way to perform such a common operation.

Or should I necessarly implement an Unit service running periodically a shell script to do the osmconvert stuff? And in that case, is there any way to use pyosmium-get-changes and nominatim add-data --diff (as is done for multiple region maps in the utils script update_database.sh) to just reindex the database with the updates relative to my sub-region? Or does my sub-region database need to be re-created from scratch every time changes occurr in the super-region.osc.gz?

[edit: corrected url]

[mtmail]

There's no tutorial or script yet that deals with non Geofabrik extracts.

The osmium tool is a bit more powerful and you wouldn't have to deal with .poly files. https://osmcode.org/osmium-tool/manual.html#creating-geographic-extracts

If you version your .osm.pbf files, e.g. by date, then you can create the change files files .osc.gz with osmium derive-changes and call pyosmium-get-changes like you see in update_database.sh.

I'm not sure how comm

[navigatrum]

Thanks! So osmium derive-changes seems the way to go.

And just to dispel any doubts, may I ask you if you can confirm that there is no way to set an import style in such a way that only what is related to a given city, or province, which is one of the cities which are 'contained' in a given Geofabrik extract, will be imported and updated into the db?

[mtmail]

You're right. The import style only select the tags (the 'what'), not the bounds (the 'where') during the import.

[lonvia]

openstreetmap.fr has extracts with matching minutely updates. If you use their polygons, then you likely can use those extracts directly. The extracts are at https://download.openstreetmap.fr/extracts/ and the replication files can be found below https://download.openstreetmap.fr/replication/ They should work nicely together with Nominatim's update mechanism.

[navigatrum]

Nice! The subregion I have to clip with Osmconvert starting from a Geofabrik extract it's already clipped in openstreetmap.fr.