The First Trilateration of the Globe 0 ▲ The Map Room 1 hour ago · Politics · hide · 0 comments J. B. Crawford’s long essay on geodesy looks at the challenge of synchronizing the datums created by the various national surveys, giving the reader sufficient background technical information for understanding the culmination of those efforts:… More No comments yet. Log in to reply on the Fediverse. Comments will appear here.