Meaning of Photogrammetry
Photogrammetry also originates from the Greek works; Photo – meaning light, Gramma – from graphy which means writing and Matron – meaning to measure. Thus, Photogrammetry is the art or science of obtaining reliable measurements from photographs.
The literal meaning of “Photography” is writing with light. It is derived from the Greek words, Photos – meaning light and graphy meaning writing. The art, science or process of taking Photographs from an airborne / space platform is called aerial photography.
History of Photography
The first permanent images made by the direct action of light were produced by the French scientist Joseph Nicephore Niepce, but were impracticable owing to the extremely long exposures required.
The discovery of first Practicable camera imaging process by Frenchman, Louis Jacques Mande Daguerre in 1839, discovery of Silver-bromide / silver iodide coating for better sensitivity by John Goddard in 1840 and designing of special new lens for photography by Joseph Petzval retailed their popularity until 1855, but it remained expensive and complicated and soon became obsolete.
William Henry Fox Talbot invented the principle of negative-positive process in 1835.
From 1835 onwards, various developments have taken place in the field of spectral sensitivity and photo processing, gradually increasing the sensitivity of light sensitive materials resulting in panchromatic photography in 1925.
George Eastman invented first Kodak camera in 1888, which is capable of recording 100 exposures.
First aerial photograph was captured by Frenchman ‘Nadar’ from a balloon in 1858, which was very pale positive image covering only a farm and three houses and inn.
In the same year colonel Aime Laussedat known as the “Father of Photogrammetry” of the French corps of engineers started researching into the possibility of preparing topographic maps from ballon photographs. He proved this in 1898.
During the period between 1858 & 1898 many enthusiasts have taken aerial photographs, kites as their platform. The kite photography obtained those days was useful to gain the meteorological data.
In 1903 pigeon flights have been carried out to take continuous pictures in a regular intervals.
In the same year, Wright brothers invented first aircraft. But the first aerial photograph with aercraft as platform was made only in 1909.
Since then, the gradual developments of Aerial Photography have put them to use for more military applications during the world war is primarily in reconnaissance.
In the period between two world wars, aerial photogrammetry for topographic mapping progressed to the point of mass production of maps.
During World War II photogrammetric technique were used extensively to meet the great new demand for maps.
Contributions in instrumentation and techniques during the past have too numerous to itemise. All the contributions take collectively, however, have made Photogrammetry so accurate, efficient and advantageous that at the present time, except for mapping small parcels, very little topographic mapping is done by other means.
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