Researched
Earth measurement and maps
Eratosthenes estimated Earth's circumference from shadow angles around 240 BC, and Greek and Roman scholars turned geometry into maps.
Open in the interactive tree →Eratosthenes' result of about 250,000 stadia lies within a few to 15 percent of the true 40,000 km, depending on the length of the stadion. Ptolemy's Geography (~150 AD) introduced coordinates of latitude and longitude. Maps became tools for navigation, trade and empire, and later for geology and weather.
Prerequisites
- Number Systems & Place Value~3000-2000 BC
- Geometry (Euclid)~300 BC
Unlocks
- Caravel & Circumnavigation~1450Charts and map projections guided ocean voyages
- Geology and deep time1788
- First Geological Map (Smith)1815
- Epidemiology1854Snow's cholera analysis was a dot map of deaths
- Weather maps and services1854
- HMS Challenger expedition1872
- Continental drift1912