<div dir="auto"><a href="https://wiki.openstreetmap.org/wiki/Overpass_API/Augmented_Diffs">https://wiki.openstreetmap.org/wiki/Overpass_API/Augmented_Diffs</a></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">нд, 21 сак 2021, 20:01 карыстальнік François Lacombe <<a href="mailto:fl.infosreseaux@gmail.com">fl.infosreseaux@gmail.com</a>> напісаў:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi all</div><div><br></div><div>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.</div><div><br></div><div>According to this discussion, it sounds to not be easy.</div><div><a href="https://help.openstreetmap.org/questions/58931/osc-to-osm-change-file-to-osm-osmium/58948" target="_blank" rel="noreferrer">https://help.openstreetmap.org/questions/58931/osc-to-osm-change-file-to-osm-osmium/58948</a></div><div><br></div><div>Currently, we convert an OSC file to CSV without any geometry information</div><div><a href="https://github.com/vdct/ProjetDuMois/blob/master/db/10_project_update.js#L275" target="_blank" rel="noreferrer">https://github.com/vdct/ProjetDuMois/blob/master/db/10_project_update.js#L275</a></div><div>with following xslt sheet</div><div><a href="https://github.com/vdct/ProjetDuMois/blob/master/db/osc2csv.xslt" target="_blank" rel="noreferrer">https://github.com/vdct/ProjetDuMois/blob/master/db/osc2csv.xslt</a></div><div><br></div><div>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.<br></div><div><br></div><div>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.<br></div><div><br></div><div>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.<br></div><div>See this chart (in French) : <a href="https://github.com/vdct/ProjetDuMois/issues/188#issuecomment-802221915" target="_blank" rel="noreferrer">https://github.com/vdct/ProjetDuMois/issues/188#issuecomment-802221915</a></div><div><br></div><div>I'll be happy to discuss about such process here as I think someone may already had to solve it.</div><div>Thanks in advance, all the best</div><div><br></div><div>François</div></div>
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