History of Aerial Photograph

Aerial photography, photogrammetry and aerial photo interpretation are relatively recently developed techniques. Their development has closely been connected with the development of aeronautics, high precision aerial camera and photogrammetric and photo interpretation instruments. An aerial photograph is a photographic image of the earth’s surface, usually taken from an aircraft, while photographic interpretation is an act of examining these photographic images for the purpose of identifying objects and judging their significance. Photogrammetry is the art of making reliable measurements from the air photographs.

 Air photo survey and the preparation of map with their help was first initiated by Aime Laussedat, a French military engineer in 1840. In 1858, a French photographer and balloonist, G.F. Tournachon took the first aerial photograph of Paris city from a balloon and that was the beginning of scientific photography from air. It was Lucida who had started preparation of maps with the help of Air Photograph taken from the balloon. The earliest existing aerial photograph was taken from a balloon over Boston in 1860 by James Wallace Black. From the time of Tournachon to the beginning of twentieth century a number of attempts were made in England, Russia, Austria and United States to take aerial photographs using balloons and simple cameras.

As an outgrowth of their use in obtaining meteorological data, kites were used to obtain aerial photographs beginning in about 1882. The first aerial photograph taken from a kite is credited to an English meteorologist E. D. Archibald. Since then, there has been a rapid development in the science of aerial photograph. The balloon has been replaced by modern aircraft and a simple hand camera has been developed into a fully automatic measuring camera for aerial exposures with high quality performance lenses and film magazine for taking several hundreds of photographs.  

Yet in the real sense such a technique was used by Canadian Surveyor general Capt. Devile in 1880. Devile used the Bridge Lee phototheodolite in surveying inaccessible areas of the Rockies and prepared their map with the help of such aerial photograph. Such systematic effort continued before the First World War. The countries involved in the First World War realized the strategic significance of the aerial surveys since the beginning of the war. In 1914 Lieutenant Law used aerial camera to obtain photographs of parts of Germany. Later, the same techniques were soon followed by the Royal Air Force, England, France and United States for aerial military reconnaissance. By that time many advancement were made in scientific and commercial uses of photo interpretation and photogrammetry.

But the real progress in this direction was could be made in 1920, when aeroplanes were invented, the first credit for which goes to Prof. B. Melvil and M.J. Grifith of Cambridge University. Gradually in course of time improvements were introduced in aeroplanes, camera and other associated tools and materials. The growth and development of this technology was put to its optimum used during the World War II (1939-1945) with the beginning of military photo reconnaissance. Practically, all the countries involved in the war made extensive use of aerial photograph. This included photographing mainly important military installations and transport facilities, air fields, ports, bridges, canal, railways and other significant landmark in enemy’s territory.

After the II World War the experience and importance of photo interpretation gained during the war was realized all over the world. The greatest contribution of war to aerial photography and photo interpretation was further realized through the training of a large number of engineers, geographers, geologists, forester, soil surveyors and others who received both training and practical experience in photo interpretation while serving in the armed forces. Upon returning to their professional activities at the end of the war, they found many civil applications of photo interpretation and demonstrated the value of the technique.

Many improvements in the quality of photographs may be attributed to war time developments in aerial photographic equipments and techniques. Intensive research has developed cameras with fast and nearly distortion free lenses, fast and dependable shutters, mountings which absorb aircraft vibrations and film drive mechanism which partly compensate for image motion. The sensitivity of film emulsions has been improved and special types of films have developed for high sensitivity for certain parts of the spectrum. Drift meters, view finders and electronic navigation aids now help the pilot to navigate his flight lines so as to maintain the required forward and side lap. Improvements were also made in stereoscopes, plotting instruments and in the technique of photo interpretation.

During the last 30 years scientific advancement has been developing at an ever increasing rate and aerial photography is not an exception. New techniques have been added to the tradition one of black and white photography exploiting a much wider part of the electromagnetic spectrum, namely colour, infra-red, colour infra-red, multiband photography and radar and thermal infra-red imagery. A new dimension has been opened up due to the advent of photographs and Multi Spectral Scanner (MSS) imageries from Orbital satellites.

Thus, a tremendous amount of information and data is now available. By 1933, the use of air photographs began to be made at commercial level. In USA aerial survey was started in 1920, and by 1938 nearly 1.6 million sq. miles of area were covered by such surveys and maps completed. It is the leading country in the field of remote sensing from air and space platforms. Space photography dates back to 1965, when 25 colour photographs of the earth were obtained from Gemini III. Since then a number of space missions by Gemini and Apollo series of rockets which took hundreds of black and white colour photographs of the surface of the earth.

The more systematic coverage of the earth surface was made by the First Earth Resources Technology Satellite, ERTS-I which was launched on July 23, 1972. Ladsat-2 was launched on January 22, 1975. The national Aeronautics and Space Administration (NASA) unmanned Skylab space vehicle was placed in orbit in May 1973. Subsequently, the manned space vehicle Skylab-II was launched on May 5, 1973, Skylab 3 and Skylab 4 on July 28 and November 16 1973 respectively. In India, the preparation of maps through aerial photographs was started after the independence. Aerial photography is controlled and coordinated by Survey of India. Three flying agencies are responsible for executing the photography and supply of photographic prints and enlargements; these are Indian Air Force, M/s Air Survey Co. Pvt. Ltd (Dum Dum) Kolkata and National Remote Sensing Agency, Hyderabad. The cartographic work through such surveys and revision of existing maps and topographical sheet is done by the Survey of India. The Government of India has established Indian Photo Interpretation Institute at Dehradun. Through aerial survey the whole country has now been completed on different scales.