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Curator's introduction

War and the threat of war have always proved great incentives for map-making. The eighteenth and early-nineteenth centuries brought both. Revolution in France kindled a chain of events that set the Continent in turmoil for decades. Napoleon took command of the French army in 1795 and began the military campaigns he hoped would make him master of Europe.

Facing the threat of invasion, the English government commissioned a military survey of the vulnerable south coast. An accurate map of Jersey had already been made, soon after a French attempt to capture the island in 1781, but this had been restricted to government use only. The new maps were to be published – and at the detailed scale of one inch to the mile.

An earlier proposal to map the whole country had failed to attract government funding, largely due to the antipathy of influential landowners in Parliament who did not relish the prospect of surveyors probing their private estates to record matters that might have taxable consequences. But now, with national security at stake, the misgivings of the landed gentry were swept aside.

Responsibility for what became an historic venture fell to the Board of Ordnance, from which the Ordnance Survey takes its name. The Board had been established in Tudor times to manage the supply of stores and armaments for the army and maintain national defences. From its headquarters in the Tower of London, engineers and draftsmen set out to produce the military maps by a system of triangulation.

A theodolite was used to measure the angles of a remote point from each end of a steel chain. The triangle formed by the known length of the chain and the two sight lines enabled the precise distance of the far point to be calculated by trigonometry. The theodolite, specially built by Jesse Ramsden, was a formidable instrument, almost a metre in diameter and weighing over ninety kilos. A four-wheeled sprung carriage pulled by two horses was needed to move it from place to place.

The survey of Kent was first to go ahead. It began in 1795 under the direction of the Board’s chief draftsman, William Gardner. Critical communication routes such as roads and rivers were to be shown clearly and accurately. Attention was paid to woods that could provide cover for ambush, and elaborate shading was used to depict the contours of terrain that might offer tactical advantage in battle.

Preliminary drawings were made at scales from six inches to the mile, for areas of particular military significance, down to two inches to the mile elsewhere. Back in the Drawing Room at the Tower of London, fair copies of the drawings were prepared at the reduced scale of one inch to the mile. From these, copper plates were engraved for printing. The map of Kent was published in 1801, and Essex soon followed.

Although fear of a French invasion faded after the decisive Battle of Trafalgar in 1805, the mapping of the south coast was extended, piecemeal, to cover the rest of the country. Impetus slowed, but the quality of the maps remained superlative. It was the first comprehensive survey since Christopher Saxton’s county maps of the 1570’s – an age away. Then, Birmingham had been too insignificant to even merit a mention. Now, it was one of Britain’s largest cities.

The success of the first maps, coupled with a growing sense of patriotism, won over the formerly reluctant landed gentry. Some in Lincolnshire and Rutland even offered to pay in advance for copies of the finished maps if the Board would speed up the surveying of their region. Being on the Ordnance Survey had become a matter of pride.

The British Library is very fortunate in possessing 351 of the original preliminary drawings made by the surveyors between the 1780s and 1840. They cover most of England south of a line between Liverpool and Hull. The collection includes maps drawn by Robert Dawson, perhaps the most talented of the draftsmen, whose work set the style for British military map making. His Survey drawings of North Wales show his skill at its best.

Being significantly larger in scale, the preliminary drawings show much more detail than the printed maps. Together, they present a picture of Regency England and Wales unparalleled in its accuracy. The picture is not one of military significance alone: the recording of archaeological features betrays the surveyors’ antiquarian interests, and the delineation of mountains reflects the new desire to see majesty in Nature.

In some eyes, the Survey itself achieved a sense of heroism. Writing at the end of the undertaking, Pilkington White eulogised "those employed on the ‘trig’ work of the Survey… the lonely days and night watches on the summits of the highest peaks… snows and terrific hailstorms at times assailing, even in summer, the solitary camp."

The surveyors’ efforts sometimes were truly heroic. Captain William Mudge and his team hauled hundreds of kilos of equipment and supplies to the windswept peak of Black Comb Mountain in Cumbria during 1807 and 1808. His work was immortalised by the poet, William Wordsworth who penned a poem in his honour when visiting the summit where the "geographic labourer pitched his tent".

Mapmakers, poets and artists had each captured the British landscape and forged it, through their different disciplines, into a single coherent vision – the vision of a nation. From the summit of Black Combe, Wordsworth looked out over the terrain Mudge had surveyed, declaring it a "display august of man’s inheritance, of Britain’s calm felicity and power!"

By the time the Ordnance Survey of Britain was completed in 1874, it had been transformed from a military necessity to an enduring symbol of national identity.

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