c. 150 CE
Ptolemy systematizes coordinates and projections
Oceans, navigation & cartography · Nautical cartography
Claudius Ptolemy’s Geography combined a gazetteer with instructions for plotting places through latitude, longitude, and projections. It was not directly a nautical chart, and no secure original maps survive, but its system enabled map reconstruction and influenced later Islamic and European traditions.
Precision, calendar, and review
- Start
- year · approximate
- Calendar and convention
- Historical-era years; the source calendar is not identified. No conversion of days is assumed.
- Year zero
- The scale goes from 1 BCE to 1 CE without year zero. Changing era names changes labels only.
- Documentary review
- Date not recorded
Reading the date: point event.
Sources
- 1. guides.loc.gov (opens in a new tab)
Source provenance and scope
- Publication date
- 2024-09-17
- What this date describes
- The cited source or edition; it may postdate the historical event.
- Bibliographic date checked
- 2026-09-23
The correspondence between this reference and individual claims has not yet been itemized.
- 2. www.loc.gov (opens in a new tab)
Source provenance and scope
- Publication date
- Pending verification: the source could not be accessed
- Bibliographic date checked
- 2026-09-23
The correspondence between this reference and individual claims has not yet been itemized.
This record is an editorial synthesis. Consult the sources to check claims and their limits. Chronological relationships alone do not establish causation.