The remnants of the 1846 mapping of Ireland, finalised during the Irish famine. These benchmarks are from the first Ordnance Survey mapping of Ireland… …to provide the information for the British Government to update land valuations for tax. Carved in the years before 1846, they were used to establish the location’s height against sea level. Trig Pillars were built on top of mountains, within sight of others. Brass ‘spiders’ on top of the pillars were the fixing point for a theodolite - the meas

38K views · 87 reactions | TOPIC: TRIANGULATION The New Prince -...