Early Charts

Mariners have had charts with accurate latitudes for about five hundred years, and there's evidence that cruder charts with latitude-type parallels existed as far back as 600 BC. Early charts were mostly sketches of coastlines and entrances to natural harbours drawn from third- or fourth-hand information.

As time passed charts improved, but errors persisted, mostly due to an inability to accurately determine longitude. This problem was solved when chronometers became reliable and were slowly adopted in the late 1700's and early 1800's. The ability to keep accurate time was the key to measuring longitudinal distance.