Most of us have come across OS Maps when doing some serious walking in the countryside.
The Ordnance Survey was, until recently, a Government organisation that has mapped every inch of the UK. The OS maps show in great detail points of interest including pubs, post offices, telephone boxes, ancient monuments, and even heights of the landscape.
Originally founded in 1791, it was the military that was charged with mapping the south coast of England driven by the fear of a French invasion.
In 1794 the first ever reading was plotted using a “triangulation” process developed by a second lieutenant and mathematician in the Royal Artillery named William Mudge.
This reading was taken from a stable “permanent” point (an upright cannon sunk into the ground). Inscriptions on the gun recorded with an inverted arrow known as a “bench mark” to mark the height.
At a point opposite Old Sarum, the early home of Salisbury, an instrument known as a theodolite was placed on top and a reading was taken to another upturned cannon 7 miles away at Beacon Hill to the North.
To recognise this important point in the history of map making, a stone was erected on the side of the road which over the years had become loose, lichen covered and overgrown.
Following an enquiry from a local history group Salisbury City Council took on the responsibility to re-set the marker stone.
Recently the City’s Information Centre took a call from the same history group who wanted to pass on their thanks to the grounds team for their work and were delighted that this important piece of British history had been resurrected for future generations of history buffs.