Introduction to Aerial Photographs
A photograph taken from an air borne platform using a precision camera is called an aerial photograph.
Aerial photographs are used in topographical mapping and interpretation.
Aerial photography in India started in 1920 when large scale aerial photographs of Agra city were obtained.
Three flying agencies have been officially authorised to take aerial photographs in India. These are the Indian Air Force, the Air Survey Company, Kolkata and National Remote Sensing Agency, Hyderabad.
Aerial photographs provide many advantages over the ground based observations. A bird’s eye view of large areas is provided by aerial photography. Aerial photograph can be regarded as a record of surface features at the time of exposure. Sensitivity of the film used in aerial photography is more than the sensitivity of human eye. Aerial photography provides a three-dimensional view of the photographed surface.
On the basis of the position of the camera axis, aerial photographs are classified into vertical photographs, low oblique photographs and high oblique photographs.
On the basis of the scale, aerial photographs are classified into large scale, medium scale and small scale.
In aerial photography, the kind of projection of image is an important aspect. The three main types of projections are parallel projection, orthogonal projection and central projection. Aerial photograph, with lots of features, is an indispensable tool in geography.