The data for this infographic comes from Wikidata.
While it took me some time to come up with the easiest approach, it eventually seems best to use a SPARQL query.
After working around it for a bit (and using Wikipedia's great Query service), I came up with this query:
SELECT ?item ?itemLabel ?start_time ?timeprecision WHERE {
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE]". }
{
SELECT DISTINCT ?item WHERE {
?item wdt:P580 ?start.
{ ?item (wdt:P31/(wdt:P279*)) wd:Q103495. }
UNION
{ ?item (wdt:P31/(wdt:P279*)) wd:Q8465. }
UNION
{ ?item (wdt:P31/(wdt:P279*)) wd:Q198. }
UNION
{ ?item (wdt:P31/(wdt:P279*)) wd:Q350604. }
}
}
OPTIONAL {
?item p:P580/psv:P580 ?timenode.
?timenode wikibase:timePrecision ?timeprecision.
?timenode wikibase:timeValue ?date.
?item wdt:P580 ?start_time.
}
FILTER ( ?timeprecision > 10 )
}
- The P580 property corresponds to "start time";
- The P31 property corresponds to "instance of";
- The possible results corrspond to types of items I'm looking for (wars, armed conflicts etc.);
- Precision > 10 means we'd get results whose start time's precision is at least "daily".