Early Days of the Ordnance Survey

Gillian Allardyce

The Ordnance Survey founder was the 3rd Duke of Richmond who between 1782 and 1795 was the Master General of Ordnance. However, the idea of a national survey came from a Mr William Roy who joined the Corps of Engineers in 1755. Whilst maps had been drawn for many years, no complete survey had been undertaken, but Roy had previously been involved in military surveying in Scotland, and in 1763 made a proposal for a national survey of Britain recognising the vulnerability to future invasion. This was refused based on cost and time, however in 1783 Roy began what was to become a triangulation scheme "for his own amusement". Barometers were used to measure height and, with an experiment with the Astronomer Royal and a Professor of Mathematics, contour lines were developed.

Hounslow Heath was used for measuring and was where triangulation was developed. Mr. Jesse Ramsden, who was a leading instrument maker constructed a three-foot theodolite for Roy, although it took three years before it was finally delivered.

Charles Lennox, the 3rd Duke of Richmond, had employed surveyors on his Goodwood Estate since 1758, and in 1782 the Duke was appointed Master General of the Board of Ordnance and the Ordnance Survey was officially launched in 1791.

Since Roy's plans for a national survey matched Richmond's own ideas for a defence policy, he made his men and equipment available for Roy's Hounslow Heath project.

William Roy died in 1790, and Richmond was able to continue with Roy's project and appointed a Mr Isaac Dalby to the Map-Drawing Board of Ordnance. Soon a Major Edward Williams and a Lieutenant William Mudge followed in the project's development.

The first published Ordnance Survey map of Kent was in 1801, drawn to a scale of one inch to the mile. The version illustrated was reduced to one inch to two miles, published in 1807.

Information sourced from ordnancesurvey.co.uk