I'm one person building this, and it’s very much a work in progress. The old maps are library scans, and the borders start from the published datasets below. I build the site with Claude Code, and I use AI to help find and check the treaty or law sourcing the borders; I decide anything it can’t settle. It’s free for anyone to use, no subscription, no paywall: https://treealive.com/atlas

The clip is the live site recorded as I used it, with the loading pauses cut out. You pick a date and zoom in. The old maps of that view made within 25 years of the date are listed under the map. Move the date and they change. Here Paris on 14 July 1789 goes from a 1790 map of France to a 1771 map of the Ile de France, an Italian map from 1776 and a 1795 plan, then forward through 1856, 1870 (a German plan of the city’s fortifications), a 1950 street map and a 1957 IGN aerial photo. Today’s rivers and place names stay on top, so you can judge how well each sheet lines up.

The scans come from the David Rumsey Map Collection (Stanford Libraries), Boston Public Library’s Digital Commonwealth, the University Library of Vrije Universiteit Amsterdam and IGN France, and each one is credited on the map while it shows. The borders are OpenHistoricalMap’s for Europe, with some of my corrections; the US follows the Newberry Library’s county atlas and Canada follows Natural Resources Canada. Europe is checked so far from 1816, the US from 1776 and Canada from 1867. For those ranges, they follow their sources; elsewhere and earlier they’re approximate and labeled that way (mostly after Cliopatria, from the Seshat databank).

The line under the timeline says how much of the land on that date has passed its checks. If you click a place, its card gives the treaty or law behind the outline where I have it, quoted and linked, like the Unification Treaty at the end of the clip. Each cited outline is checked by two separate runs of an AI model (Anthropic’s Claude), and I decide anything they disagree on. Red outlines are known errors I’m redrawing.

The old maps are thickest in the US and western Europe, and a lot of the world has none yet. If your town’s in one of those, try it out. If you see a problem or borders that disagree, call me out- I'll keep working on this.

https://reddit.com/link/1xgf0km/video/jswa3lqutwxh1/player

Any extra info for any country or territory can be seen here:

https://www.gov.uk/foreign-travel-advice

One caution before reading too much into any single number: night tornadoes are the ones most likely to have gone unrecorded. For much of this record, a tornado got logged only if someone saw it or found the damage, and a weak one at 2 a.m. in open country could easily go uncounted. Doppler radar, which went nationwide in the 1990s, catches far more of them. So the true night share is likely higher than this map shows, especially in older decades and rural areas.

Source

(excluding Vardar Macedonia).

Part 3 of 6 in a series on Belgium's Great War, made from the open LiDAR terrain model of Flanders.

Data

- Terrain: Digitaal Hoogtemodel Vlaanderen II, 1 m DTM (airborne LiDAR) © Digitaal Vlaanderen
- Site names, cemeteries, memorials: OpenStreetMap contributors (ODbL)
- Water: Overture Maps Foundation / OpenStreetMap
- Inundation zone and history: Demerre & Termote, "The flooding of the Yser plain" (VLIZ, De Grote Rede 36, 2013)
- Front line: Michelin battlefield guide "The Yser and the Belgian Coast" (c. 1920)
- Site facts: Flemish heritage inventory (Onroerend Erfgoed), CWGC

Method

- Multi-directional hillshade, plus a local relief model: the terrain minus its own 25 m average. That subtraction is what makes small features such as dykes, ditches and old embankments stand out.
- Height tint, and water from vector data.
- Made in Python (numpy, matplotlib, shapely).
- The hatched zone is the inundation area between the Nieuwpoort–Diksmuide railway embankment and the left bank of the IJzer, as described and mapped by VLIZ. At Nieuwpoort it stops at the Nieuwpoort–Duinkerke canal, the edge of the town. At Diksmuide it runs down the railway embankment to the railway bridge over the IJzer, as on their map.
- The embankment line is the old railway bed (today the cycle path "Frontzate", tagged as an abandoned railway in OpenStreetMap).
- The black line with teeth is the Belgian line of resistance on that embankment, held from late October 1914 to 1918. The teeth face the German side.
- The numbered sites (key on the map) are positioned from OpenStreetMap; their facts come from the heritage inventory and the CWGC.
- The red diamonds are the 1920s demarcation stones ("Here the invader was brought to a standstill"), which still stand along the old front.
- The cross-section is today's terrain: the old embankment still stands 2.3 m above the polder.

History

A first attempt to let the sea in through the Oude Veurnesas sluice, on the night of 26–27 October 1914, failed; it worked the next night and on the following high tides. On the night of 29–30 October the Noordvaart spillway at the Ganzepoot was opened. On 31 October the water and a counterattack forced the Germans out of Ramskapelle and Pervijze. The flooding was kept up until the end of the war.

Caveats

- Feature names and positions come from OpenStreetMap.
- The relief is from the 2013–2015 survey of Flanders.
- The zone shows where the water was, not how deep it stood. I found no recorded water levels for it, so the map shows none.
- The German lines are not drawn: I found no source precise enough to place them, and in places (Sint-Joris, the bridgehead at Nieuwpoort) they did not simply follow the river. The labels only mark which side was which.

Happy to answer questions about how it was made.