[OSM-dev] Get geometries out of OSM changes file

[Roland Olbricht]

Hi François,

> You link points me to an OverpassAPI endpoint and I don't get how I'm
> able to produce augmented diff from an osc file.
> Osmchange is mentioned as a reader of augmented diff, but not as a producer.

To give a high level overview: The core problem is the the OSC file
itself does not contain the geometric information.

If your process allows to load data over the internet during processing
then Overpass API (or potentially other OSM APIs) will allow you to
fetch the missing data on the fly.

If it is easier for you to maintain a full database, run a patch and
extract then on the fly then you should look at what Osmium (and again,
some other tools) do.

In any case, there is a caveat that the timestamps in the database are
not strictly in line with the minute updates. As there is no direct
connection between events on nodes and events on ways or relations, it
may happen that a way get it final geometry not before half an hour
later. The new diff process should have mostly mitigated the situation.
Keep this in mind when the basic process has been set up.

I'm sorry, from
https://github.com/vdct/ProjetDuMois/blob/master/db/10_project_update.js#L275
I have not been able to figure out what is in "osh.pbf" to decide
whether there is already somewhere the geometry.

Best regards,

Roland