Sunday, August 7, 2011

British Aerial Photography and Photographic Interpretation on the Western Front - Pt 2

Back to Part 1

The Pre-Cursor 1849 to August 1914

At the start of the twentieth century the evolution of camera design and photography (fast exposures and camera miniaturisation, automation/remote control and stabilisation) led to two main uses for photographs taken from a tethered aerial platform; survey and observation, both of which had direct military applications.  Survey provides the cornerstone of accurate mapping which when overlaid with observations; previous intelligence gathering and reconnaissance, provides military commanders with a two-dimensional representation of the area over which military operations are envisaged or planned.

The first successful experiments in photographic topography were carried out in 1849 by a French army engineer called Aimé Laussedat.  Laussedat pioneered the use of aerial photography as a surveying tool to map the city of Paris.  He used unmanned balloons and kites from which he suspended his camera.  In the mid 1880s E. G. D. Deville, the Surveyor General of Canada, refined and adapted Laussedat’s techniques for use in the Canadian mountains.  By comparing the terrestrial photographs taken from various locations and incorporating standard surveying techniques a third dimension was added to the mapping and this resulted in the first accurate contoured maps being produced.  Deville’s third dimensional technique was improved in late 1883 when Cornele B. Adams, a US Army officer, was given a patent for a ‘method of photogrammetry’ that involved the capture of two aerial photographs of the same area with a camera from two different positions.  The resulting stereo image was then used to create a topographical map.  Twenty years before the advent of powered flight the utility of aerial photography in support of accurate map production had been clearly demonstrated.

The use of the nascent aerial photography capabilities was not immediately apparent to many military officers.  None of the combatants in the Crimean war (1853-1856), the conflict closest to aerial photography’s birth, appear to have attempted to photograph from balloons.  In Britain the War Office could not be convinced of the balloons potential consequently they were not operated at all by the British.  The Civil War in the USA was the first large-scale conflict where balloons played a role on both sides.  The first reported military application of aerial photography is believed to have occurred in 1862 during the Union siege of Richmond, Virginia.  An aerial photograph of the town was taken from an observation balloon.  Two gridded map-like prints were produced one for General McClellan, the Union commander, the second for the balloon crew who observed the activity taking place in Richmond from a height of 1,500 feet.  Communication was established by telegraph and the balloon observers indicated movements within the town by using a grid marked on the photographs (Hamish B. Eaton, APIS Soldiers with Stereo: An Account of Army Air Photographic Interpretation, (The Intelligence Corps Museum, 1978) p. 1.).  A British eye witness to the event, Captain F. Beaumont Royal Engineers (RE), who served with the Union Army’s Balloon Corps in the American Civil War, wrote:

‘I once saw the fire of artillery directed from the balloon; this became necessary, as it was only in this way that the picket which it was desired to dislodge could be seen.’  J. M. Bacon, The Dominion of the Air, (Project Gutenberg Ebook, 1903).

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