Photogram metric surveying or photogrammetry is
the science and art of obtaining accurate measurements by use of photographs,
for various purposes such as the construction of planimetric and topographic
maps, classification of soils, interpretation of geology, acquisition of
military intelligence and the preparation of composite pictures of the ground.
The photographs are taken either from the air or from station on the ground.
Terrestrial photogrammetry is that Brach of photogrammetry wherein photographs
are taken from a fixed position on or near the ground. Aerial photogrammetry is
that branch of photogrammetry wherein the photographs are taken by a camera
mounted in an aircraft flying over the area.
Mapping from aerial photographs
is the best mapping procedures yet developed for large projects, and are
invaluable for military intelligence. The major users of aerial mapping methods
are the civilian and military mapping agencies of the Government.
The conception of using
photographs for purposes of measurement appears to have originated with the
experiments of Aime Laussedat of the Corps of the French Army, who in 1851
produced the first measuring camera. He developed the mathematical analysis of photographs
as perspective projections, thereby increasing their application to topography.
Aerial photography from balloons probably began about 1858. Almost concurrently
(1858), but independently of Laussedat, Meydenbauer in Germany carried out the
first experiments in making critical measurements of architectural details by
the intersection method in the basis of two photographs of the building. The
ground photography was perfected in Canada by Capt. Deville, then Surveyor
General of Canada in 1888. In Germany, most of the progress on the theoretical
side was due to Hauck.
In 1901, Pulfrich in Jena
introduced the stereoscopic principle of measurement and designed the stereo
comparator. The stereoaitograph was designed (1909) at the Zeiss workshops in
Jena, and this opened a wide field of practical application. Scheimpflug, an
Australian captain, developed the idea of double projector in 1898. He
originated the theory of perspective transformation and incorporated its
principles in the photoperspecto graph. He also gave the idea of radial
triangulation. His work paved the way for the development of aerial surveying
and aerial photogrammetry.
In 1875, Oscar Messter built the
first aerial camera in Germany and J.W.Bagloy and A.Brock produced the first
aerial cameras in U.S.A. In 1923, Bauersfeld designed the Zeiss
stereoplanigraph. The optical industries of Germany, Switzerland, Italy and
France, and later also those of the U.S.A and U.S.S.R. took up the manufacture
and constant further development of the cameras and plotting instruments. In
World War II, both the sides made extensive use of aerial photographs for their
military operations. World War II gave rise to new developments of aerial
photography techniques, such as the application of radio control to photoflight
navigation, the new wide-angle lenses and devices to achieve true vertical