'Trig Points’ or ‘Trig Pillars’ were once
part of a state of the art network built to
begin the retriangulation of Great
Britain.
6,500 shining white monoliths standing
atop hills, mountains and high points
used mathematics to accurately map
Great Britain.
• Beginning in 1936 this massive task
was not completed until 1962
• Triangulation is a mathematical
process that made accurate map
making possible before GPS and
altimeters
• 5,500 trig points still remain in place
today
• The last used trig pillar was on June
4th 1962 and sits on Thorney Gale,
Westmorland, Cumbria.
• The survey network was accurate
down to just 20m across the whole
GB
• Modern receivers which now make
up the OS network are coordinated
to an accuracy of just 3mm!
• Like an iceberg, there is more pillar
below the surface than above
