system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How could we have had so accurate world-maps before we could fly/see the world from space?

For example in the 1700's we already had very accurate world maps.
gpt
Surveying. Surveyors took records of how far they travelled, how far between landmarks, the angles between landmarks from their positions, and so forth and so on, creating a network of measured triangles. This allowed the creation of accurate maps.