Managed a few Trig points over the Easter weekend …..
Yesterday marked the 80th Anniversary of the Trig Pillar .
On 18 April 1936 a group of surveyors gathered around a white concrete pillar in a field in Cold Ashby and began the retriangulation of Great Britain. That trig pillar is still standing 80 years on, along with thousands more around the country. We’re celebrating by sharing the story of the humble trig pillar, still much loved by walkers today, and giving you the chance to join our celebrations with The Trig Pillar Trail Challenge.
The shining (sometimes) white monoliths are now instantly recognised by any walker, or geography lover and have inspired many a trigbagger. They’re quintessentially British, and even made it onto Bill Bryson’s list of favourite British items in his 2015 book ‘The Road to Little Dribbling’. But what were they for? Now largely redundant, back in 1936, they formed a state-of-the-art network built to re-map Britain, dreamt up by Brigadier Martin Hotine. Responsible for the design, planning and implementation of the retriangulation, Hotine also designed the iconic trig pillar to provide a solid base for the theodolites used by the survey teams to improve the accuracy of their reading.
Some 6,500 were built, to be used for triangulation, the mathematical process that makes accurate map making possible. It works by determining the location of a point by measuring angles to it from known points at either end of a fixed baseline and in this case, those known points were the 6,500 trig pillars, across the country. OS surveying teams spent 26 years gathering measurements across Britain to create a highly accurate map of the country, but time and technologies have moved on enormously to the point where the traditional trig pillar is now obsolete in its original guise. They still act as a beacon for many an outdoors lover, but they no longer help shape our maps. Look out for tomorrow’s blog where we’ll share more detail on the history of the trig pillar, how they were built and used, the inner workings and much more.
Although 6,500+ trig pillars were built, hundreds have been lost to housing developments, farming, coastal erosion and other causes. The greatest source of information on trig pillars (and other Ordnance Survey surveying marks) is
www.trigpointing.uk. Users on there regularly ‘bag’ trig pillars and take photos to track their condition.
While there are many trig-baggers out there, trig-bagger extraordinaire Rob Woodall completed his 13-year mission to bag all of Britain’s trig pillars last weekend in Fife. He’s bagged 6,190 trig pillars, a seriously impressive achievement. We joined his final bagging expedition and awarded him a mounted flush bracket to mark the moment. Look out for Thursday’s blog with more details on his final trig-bagging adventure.
TP 6242 - Suffield
And
TP 2392 - Coomb Hill
en.wikipedia.org
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