YearMaps adheres to radical transparency in historical geography. Our maps and encyclopedic dossiers synthesize verified, peer-reviewed open geospatial datasets under open licenses.
Compiled by T. Matthew Ciolek. YearMaps uses two of its data sets: the list of caravan halting places, and the route segments of the Silk Road between Dunhuang and Kashgar. Other route lines on the atlas are schematic, drawn between documented stations.
Authoritative, public domain map dataset providing shaded relief, physical coastlines, continental landmass polygons, and hydrographic lines built by cartographers for cartographers. It is the source of the river lines on the map and on river pages.
The river network of the Ministry of Jal Shakti and ISRO. Where Natural Earth draws an Indian river coarsely or not at all, YearMaps takes its line from India-WRIS instead, among them the Barak and the Sharavathi.
The ground height at both ends of each mapped river, used only to tell its source from its mouth where the coastline cannot: water runs downhill, so the higher end is the source. A river whose ends differ by less than 25 m, and that no other test can orient, is drawn without source and mouth markers. Heights are not shown on the site.
A free and open knowledge base acting as central storage for structured entities, linking historical monarchs, sovereign capitals, dates, and bibliographic citations.
Introductory article extracts provide narrative context on individual dams, peaks, lakes, rivers, cities and archaeological sites. An article is used only when it passes two checks: its coordinates must lie within a set distance of ours, and its own short description must say it is the right kind of thing, so that a river is not given the article of the province named after it. Longer pages also carry up to four body sections of the same article. Each page links back to the source article.
Supplies the "Key Facts" tables: river lengths and discharge, lake depths, dam heights, city elevations, and for historical states their capitals, languages, predecessors and successors. Also the source for country population fallback, capitals, land and maritime neighbours, the list of UNESCO World Heritage Sites with inscription year and criteria, and the caravanserais shown on the map and on trade route pages. Each table links to the Wikidata item it was read from.
Current country indicators shown on country pages, each with its reference year: population, GDP and GDP per person, life expectancy, urban share, population density, forest and arable land, access to electricity and internet use.
Plain-language notes on each country: location, climate, terrain, highest and lowest points, natural resources, land use, natural hazards, languages and religions. The Factbook is no longer updated, so an archived edition is used and its date is printed with the text.
A short visitor-oriented passage on island, country, state and region pages. Guides for islands are accepted only when the guide's own coordinates agree with ours.
A community-built gazetteer of ancient places, recording ancient names, feature types, provincial context and occupation date ranges for sites across the Greek and Roman world.
Harbour characteristics including approach channel depth, anchorage and cargo pier depths, tidal range and maximum accommodated vessel class — the physical constraints that determine what each port can handle. Every harbour is listed on the page of the sea it lies on.
The limits of the oceans and seas defined by the International Hydrographic Organization, as published by Marine Regions (Flanders Marine Institute, 2018, IHO Sea Areas version 3). Each harbour is placed on the sea whose area contains it or lies nearest to it.
Year-by-year boundary polygons for more than 1,600 political entities, published by the Seshat Global History Databank project. Its 13,800+ dated shapes supply the empire territories and era maps, the pre-war borders of the World War II map and the territory outside Europe on the World War I map.
Dated front lines for the Western, Eastern, Italian, Balkan and Romanian fronts, battle areas, 1914 European borders and each country’s alignment by date, used on the World War I day-by-day map.
Historical borders were rarely line-drawn razor edges; rather, they existed as zones of suzerainty, tributary frontiers, desert buffers, and fortified limes. When visualizing pre-modern empires, YearMaps combines core administrative territory polygons with frontier buffer zones to accurately convey the reach of imperial authority.
All vector geometry is indexed in WGS84 coordinate space and rendered client-side using GPU hardware-accelerated shaders and vector tiles.
