On the 6th Day of Christmas Trigmas the Ordnance Survey sent to me......Trigopoly - #6 Meddat
All pillars are trigs BUT not all trigs are pillars. This is the case with this trig - It's a large bolt which is an OS survey marker, usually placed in natural rock but in this case, it's on the roof of the old WW2 building. This means you won't actually get to see it but trust us, it is there.
*** THE FARMER HAS REQUESTED THAT THE CACHE IS NOT VISITED WHEN IT IS DARK - PLEASE RESPECT HIS WISHES ***
Trigpoints are the common name for "triangulation pillars". These are concrete pillars, about 4' tall, which were used by the Ordnance Survey in order to determine the exact shape of the country. They are generally located on the highest bit of ground in the area, so that there is a direct line of sight from one to the next. By sitting a theodolite (an accurate protractor built into a telescope) on the top of the pillar, accurate angles between pairs of nearby trigpoints could be measured. This process is called "triangulation". A major project to map out the shape of Great Britain began in 1936. The network of triangulation pillars, with accurately known positions, led to the excellent OS maps which we enjoy today.
