How do I download OSM power grid data (for India) for a particular year or at a particular time point? I do not want the latest maps but those with specific timestamps.
OpenStreetMap cannot tell you what the power grid was like at a particular time point. What it can tell you is what OpenStreetMap had mapped for the power grid at a particular time point. The two are slightly different concepts - if a power line was added to OpenStreetMap, you don't know if it's a newly constructed line, or a line that had existed for some time but wasn't yet mapped.
To get the data, start by downloading a full history extract (file with
.osh.pbf) from the Geofabrik Download server and use osmium-tool's time-filter command to create a PBF with a command like
osmium time-filter history.osh.pbf 2020-01-01T00:00:00Z -o extract-20200101.osm.pbf.
You will need to then filter the file for the parts of the power network you want. Since you haven't specified exactly what you're after, it's hard to know the best method. Popular methods include
- osm2pgsql with a style that only defines the features you want,
- osmium-tool with tag filtering,
- QGIS with suitable definitions for tags, or
- ogr2ogr with suitable definitions for tags