Methodology and limitations
Human Currents draws 1,459,578 lives as arcs from birthplace to deathplace, plus 2,493,655 people who are still alive and so appear as single anchored points. Every figure below is measured, not estimated.
What the data is
Everything comes from Wikidata, the structured database behind Wikipedia, queried through the free QLever endpoint. A person appears here only if Wikidata records both a birthplace that can be placed on a map and a usable birth date. Person details are fetched live from Wikidata and Wikipedia when you click someone; nothing about you is sent anywhere, and the site has no backend, no accounts and no tracking.
This is a map of what encyclopedias remember
It is not a map of human importance, achievement, or worth. Wikipedia and Wikidata record the past unevenly: European lives more than others, men more than women, recent centuries more than ancient ones, and written cultures more than oral ones. A region that looks empty here was never empty of people — only of people whose names were written down and later transcribed into a database. Read the bright clusters as evidence about record-keeping at least as much as about history.
Nothing is invented
- No fabricated coordinates. Where a birthplace is recorded only as a country or region, the person is excluded from the map rather than dropped onto a country's centre point.
- No fabricated dates. Wikidata records how precisely each date is known. A life recorded only to the century is shown as a century, never as a made-up exact year. In deep antiquity, where most records are that coarse, the map says so on screen.
- No silent disappearances. Every person removed by a cleaning rule is counted below.
Who was excluded, and why
| Reason | People |
|---|---|
| Birthplace recorded only as a country or region | 138,264 |
| Birthplace has no coordinates in Wikidata | 33,848 |
| Implausible lifespan (over 122 years) | 2,430 |
| Death recorded before birth | 1,753 |
| Implausible year | 14 |
| No usable birth date | 6 |
4,129,548 people were considered, 3,953,233 kept and 176,315 excluded — the totals reconcile exactly. A further 189,810 people in Wikidata have a recorded deathplace but no birthplace at all; they never enter this pipeline, so they are reported here rather than being quietly absent.
What you are seeing at any moment
An arc exists while its person is alive: it appears at birth and disappears at death. Because some eras hold far more recorded lives than can be drawn at once, each moment shows the most-noted lives of that era and says how many it is showing out of how many exist. The aggregate city-to-city flows, by contrast, are always computed from every qualifying life, including those whose individual arc is not drawn.
"Most noted" means how many language editions of Wikipedia carry an article about someone. It is a measure of attention, not of merit.
How much of the data actually reaches the map
Being honest about this matters more than the number flattering us. Drawing every life at once would mean sending hundreds of megabytes and rendering far more than a screen can distinguish, so each era ships only its most-noted lives:
| In the data | Drawable on the map | |
|---|---|---|
| Completed lives (arcs) | 1,459,578 | 731,615 (50%) |
| Living people (points) | 2,493,655 | 619,280 (25%) |
Search is the complete path: all 3,420,902 named people are indexed, and selecting anyone opens their record whether or not their arc is being drawn. So nobody is unreachable — but at any given moment the map is showing you the best-documented half of history, not all of it.
Known limitations
- A recorded place of death is not always a destination in life — it may be a hospital, a battlefield, or somewhere a person was travelling through. Individual arcs deserve that caution; the aggregate patterns are more robust.
- Occupations come from Wikidata's own categories and are grouped by majority vote. Polymaths land in whichever domain Wikidata subdivides most finely, which is why Leonardo da Vinci is filed under science rather than visual arts.
- Places are rolled up to their parent city, so a village birth is grouped with its nearest city for the flow view while the person's own exact birthplace is still what gets drawn.
- Modern political borders and place names fade in only as the timeline approaches the present, because they are anachronistic over older lives. They are still modern borders, not historical ones.