The Salt Flats Are Not Flat - They Are Level

"The salt flats are perfectly flat - a vast, level surface that proves the Earth is flat."

Measure a big 'flat' place with GPS (or just read what has already been measured): the Bolivian salt flat Salar de Uyuni has been surveyed with kinematic GPS, and the roads across the Utah salt flats have been levelled. Compare the measured surface with the surveying definition of 'level'.

'Level' means conforming to the Earth's surface - a curve, not a plane. Surveying's definition: 'The true level is a curve conforming to the surface of the earth' (A Treatise on Practical Surveying). A surface made by evaporating water is level - it curves exactly as the globe predicts.

Bolivia: the GPS digital elevation model shows a complex surface with an elevation range of only 77 cm over 50 km - from 3,696.87 m in the broad depression along the southern boundary to 3,697.64 m at the northeast corner. Utah: the roads built across 47 miles of the Bonneville salt flats have 53 feet of elevation change - a 0.02% slope. It is not a hill; it is level.

The flat-earth community's favourite 'perfectly flat' places are level - which, by the surveyors' own definition, means curved. The word 'flat' and the word 'level' are not the same thing, and the measurements show which one the salt flats are.