Early Ordnance Survey baseline. Map showing the baseline measured across Hounslow Heath (now part of London), England, in the summer of 1784. This all

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Early Ordnance Survey baseline. Map showing the baseline measured across Hounslow Heath (now part of London), England, in the summer of 1784. This allowed theodolite measurements of angles to be used to calculate and map other locations during this 1784-1796 survey of England and Wales. For this triangulation process to be accurate, extremely precise baseline measurements were needed. This work was first published in Philosophical Transactions of the Royal Society, then in volume one of a 1799 report by Mudge and Dalby for the UK's Board of Ordnance. This work led to a UK national mapping agency, the Ordnance Survey.

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Size: 7051px × 2543px
Photo credit: © ROYAL ASTRONOMICAL SOCIETY/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

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