Happy Anniversary, trig pillar

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wayn0
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Happy Anniversary, trig pillar

Post by wayn0 » 01 April 23 9:15 pm

87 years ago this month, the 18th to be exact in 1936, a group of surveyors gathered around a white concrete pillar in a field in Cold Ashby and began the retriangulation of Great Britain.

This trig is still there and can be visited.

Cold Ashby (PP076)
N52° 23.013' W1° 3.296'


A history of the trig pillar | Ordnance Survey


The original triangulation of Great Britain (Principal Triangulation) was carried out between 1784 and 1853. This provided the foundation for the Ordnance Survey mapping of the country. In 1935 Major-General Malcolm MacLeod, set out to modernise the country’s triangulation, and in a military style operation, called Retriangulation, running from 1936 to 1962, hundreds of triangulation stations were installed up hills and mountains in order to make the mapping of the country more accurate. Several thousand secondary points were placed across the country. Many have been lost to development and other reasons but many are still sitting quietly awaiting trig-hunters.

The last trig pillar from which retriangulation observations were made was Thorny Gale in Cumbria on 4th June 1962. It has a similar plaque to the one found at Cold Ashby. This can also still be visited.

Thorny Gale (NY71T025)
N54° 31.212' W2° 16.296'


Not every Australian state has concrete trig pillars but we all know what they look like. The Hotline design was mimicked in NSW but I don't know when and where the first one was installed. Anyway, there's some interesting reading in the above link for some interested in trigs.

Cheers

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