2. Atlas: Discovering Linked Places

Forthcoming feature (beta)

Atlas is the new map-first way of exploring the World Historical Gazetteer. It is in active development and currently available to WHG staff and invited beta testers only, behind a beta toggle. These pages describe how it works in plain language; when Atlas ships they will move into Guides & Tutorials.

2.1. The problem Atlas solves

The same real-world place is described, over and over, by many different sources. GeoNames, Wikidata, OpenStreetMap, the Getty Thesaurus, historical gazetteers, and data contributed by researchers all record their own version of it — each with its own spellings, coordinates, dates, and categories.

WHG brings roughly 47 million of these records together in one place. That is wonderful for coverage, but it means that a single city can show up dozens of times. Search for Istanbul and you might find separate records for Byzantion, Constantinople, Constantinopolis, Tsargrad, Qusṭanṭīniyya, and İstanbul — all the same place on the ground, scattered across sources and centuries.

Atlas’s job is to recognise that these belong together, and to show you one place, many sources, instead of a pile of look-alikes.

2.2. What Atlas does

As you explore the map, Atlas groups records that refer to the same place and presents each group as a single result you can open up to see all its sources. Nothing is decided in advance and frozen — the grouping is worked out on the spot, live, from the records your search actually returns.

Think of it like a librarian who, faced with a stack of index cards written by different people in different languages, quietly sorts them into piles — one pile per real place — while you watch.

2.3. How Atlas decides two records are the same place

Atlas never relies on a single clue. Like a good detective, it weighs up several kinds of evidence and asks how strongly, taken together, they suggest that two records describe the same place:

  • Name — do the names sound alike, even across different alphabets and languages? Atlas compares the sound of names, not just their letters, so it can tell that Köln and Cologne, or القاهرة and Cairo, are close relatives. (This is powered by WHG’s phonetic matching.)

  • Location — are the two records in the same spot on the map?

  • Time — do their date-ranges overlap? A record for a Roman fort and a modern town in the same place may be different things worth keeping apart.

  • Kind of place — are they the same type of thing — a city, a river, a temple? — judged using the Getty Art & Architecture Thesaurus, a standard hierarchy of place types.

  • Stated links — has anyone explicitly said “these two are the same” (or “these are not the same”)? Authorities like the Library of Congress and Wikidata publish such links, and WHG contributors can add their own.

Each clue produces a score, and the scores are combined into a single measure of how likely it is that two records are the same place.

2.4. You are in control: the grouping dial

Different questions call for different strictness. A quick overview might want places grouped generously; careful scholarship might want only near-certain matches merged.

So Atlas gives you a dial (a slider). Slide towards loose and more records merge together; slide towards strict and only the most confident matches are grouped. You can even adjust how much each kind of evidence counts — for instance, leaning more on names and less on exact location when you are working with sparsely-located historical data. Every adjustment re-groups the map instantly.

2.5. It all happens in your browser

The grouping is computed on your own device, in the browser, in a fraction of a second. That is what makes the live dial feel instant — there is no round-trip to a server each time you nudge it.

It also has an important privacy benefit. In the companion Collaborative Workbench, you can bring your own place data and see how it lines up with WHG. Because the matching runs in your browser, your unpublished data never has to leave your computer to be compared against the gazetteer.

2.7. Why not just fix the groups once and for all?

Older versions of WHG did exactly that: places were grouped a single way, in advance, and that was that. But historical places are genuinely contested — experts disagree about whether two names refer to one place or two, and the right answer often depends on the period and the research question. A single frozen answer cannot serve everyone.

Atlas embraces that. Instead of one fixed set of groups, it gives you a transparent, adjustable view you can tune to your own needs — and it improves continuously as authorities publish new links and contributors share their expertise.

2.8. What’s coming

  • The map-first Atlas interface, with live grouping and the strictness dial.

  • Contributor tools to confirm or reject links, shared with the Collaborative Workbench.

  • Grouping that draws on WHG’s full range of evidence — name sound, location, time, place type, and stated links — all combined in your browser.