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

[François Lacombe]

Thank you Darafei

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.

Any extra elaboration will be welcome, all the best

François

Le dim. 21 mars 2021 à 18:17, Darafei "Komяpa" Praliaskouski <me at komzpa.net>
a écrit :

> https://wiki.openstreetmap.org/wiki/Overpass_API/Augmented_Diffs
>
> нд, 21 сак 2021, 20:01 карыстальнік François Lacombe <
> fl.infosreseaux at gmail.com> напісаў:
>
>> Hi all
>>
>> For the needs of ProjetDuMois statistics computing chain, I'm looking for
>> an appropriate logic to get geometries associated with osm changes in an
>> osc file, particularly for past versions.
>>
>> According to this discussion, it sounds to not be easy.
>>
>> https://help.openstreetmap.org/questions/58931/osc-to-osm-change-file-to-osm-osmium/58948
>>
>> Currently, we convert an OSC file to CSV without any geometry information
>>
>> https://github.com/vdct/ProjetDuMois/blob/master/db/10_project_update.js#L275
>> with following xslt sheet
>> https://github.com/vdct/ProjetDuMois/blob/master/db/osc2csv.xslt
>>
>> We now aim to group and count changes against some administrative
>> boundaries. As a given feature can change of admin area between two
>> versions, we must filter the changes we're interested in, intersect each of
>> them with selected admin boundaries and finally count how may they are in
>> each admin boundary.
>>
>> Despite I'll be able to get lat/lon for nodes, rebuild linestrings for
>> ways will be tricky as we'll have to not only check against nodes ids but
>> timestamps as well.
>>
>> It's not a problem to do that each day with daily updates but issues
>> occurs when we drop the database and try to get back 2 or 3 month with no
>> geometry history at all.
>> See this chart (in French) :
>> https://github.com/vdct/ProjetDuMois/issues/188#issuecomment-802221915
>>
>> I'll be happy to discuss about such process here as I think someone may
>> already had to solve it.
>> Thanks in advance, all the best
>>
>> François
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>>
>
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