Early cartographers relied on astronomical observations

Position 1: Today, satellite-based positioning systems have effectively eliminated the measurement errors that once made cartography an exercise in educated approximation.

Position 2: These sources, however, were frequently imprecise, resulting in coastlines and landmasses that were significantly distorted.

Position 3: As a result, successive editions of world maps became progressively more faithful representations of actual geography.

Position 4: Early cartographers relied on astronomical observations and travellers' accounts to construct maps of the known world.

Position 5: The invention of the marine chronometer in the eighteenth century allowed navigators to determine longitude accurately for the first time.