Historical Notes: Air reconnaissance on the Western Front

THOSE WHO followed the air campaign over Kosovo and Serbia will have noticed the large number of air reconnaissance photographs published in the media and on the World Wide Web. Every day, Nato released air photographs of the ground targets which were being attacked.

Most of these photographs published on the web were taken from satellites, and one can only wonder at the detail shown when one considers that they are taken with cameras perhaps 200 miles away from the target. The photographs are analysed by specialist photographic interpreters, who apply their skills to "interpret" the information needed by Nato, to define their targets, avoid civilian damage and assess the effects of weapon attack.

The interpreters' skills require specialist training in order for objects of similar size and shape to be correctly identified, for example differentiating between barracks and blocks of flats, military warehousing from factories, military vehicles from civilian. Photographic Interpreters (PIs) must also be able to work out the length, breadth and height of objects to a high degree of accuracy, and, from their military knowledge, identify unit sizes and formations by correctly identifying military equipment.

In modern conflicts such as the Gulf War and the Balkans including Kosovo, the PIs have had the advantage of apparently permanent surveillance from satellites to give a wide perspective, but they also have the additional assets of low-flying photo-reconnaissance aircraft to investigate specific target areas. In addition the PI can now call upon unmanned "drone" aircraft that can not only loiter over a target but can send back "real time" television pictures to the PI. He or she is then able to analyse the target, call down artillery or air strike, observe the attack and analyse the result.

So much for modern warfare, but it is nothing new. Over 80 years ago, in January 1915, the first photographic section of the Royal Flying Corps was set up to take and interpret aeroplane photographs over the Western Front. From that small beginning rose a photographic reconnaissance organisation that by 1918 had taken over 100,000 photographs on the Western Front alone. The first PIs were self-taught, but by 1916 the first training courses for Photographic Interpreters were started.

PIs learned how to decipher size, tone, shape, shadow and associated features, and to scale and accurately measure objects on the prints. From this training, they could find machine-gun positions, artillery, communication cables and all kinds of things in the devastation of the battlefields of northern France.

During the First World War, all air photos were taken on glass plates which had to be changed in the air, usually by hand; in some cases they were also developed in the air. Special cameras were developed including stereo cameras, which, by providing a three-dimensional image, helped to identify enemy camouflage; experiments were also undertaken with infra- red photography.

The PIs' skills that were developed and practised so effectively during the First World War were used with even greater effect during the Second. But those same skills have been used in the same way, albeit with much more sophisticated equipment, in the Gulf War, and currently in the Balkans and Kosovo.

My new book looks at the history of aerial photography and intelligence in the First World War. Concentrating on specially annotated air photographs from the Imperial War Museum's Box Collection, plotted on accompanying trench maps, it covers seven battles on the Western Front from early 1915 to 1918, and is the first book to cover First World War battles from the original air reconnaissance photography. It provides the reader with a view of the Western Front as seen by the Royal Flying Corps, but not seen since 1918.

Nicholas Watkis is the author of `The Western Front from the Air' (Sutton Publishing, pounds 20)