What to know before you go for Aerial Photography

by Alice Wilson SEO Executive A photograph taken from the air is called an aerial photograph. These photos are usually taken vertically with the help of cameras that are installed on air crafts. A number of factors distinguish these photographs from each other and they are segregated by identifying the overlap, scale and type of film. These are the basic things that are seen and analyzed. Apart from these, there are other specifications like focal length, stereoscopic coverage, fiduciary points, index maps and flight lines.

Films

White and black film is used for most aerial photography ventures. Some special projects may require the use of infrared, color and false colored infrared films for filming purposes; as they are the main attractions of aerial photography today.

Focal length

Focal length is the distance from the center of the camera lens to the film, which is the focal plane. The image gets distorted as the focal length is decreased. Calibration of the camera tells you the real focal length of the camera.

Scale:

This is actually a ratio. This takes into account the distance on the photograph and the ground distance between two points. It simply says that 1 unit on camera is equal to “y” distance in actual landscape.

The two popular terms associated with the scale are large and small scale. The large scale allows a greater, finer coverage of smaller areas. Small scale enables the covering of larger areas but lack the detail as in case of large-scale photographs.

Fiducial marks

These are tiny registration points which are present on the side margins or corners of a photograph. When the aerial camera is calibrated, these marks are inbuilt in them. These are usually used by cartographers.

Overlap:

It is the extent to which one photograph covers its successive photograph. It is expressed in percentages. This overlap can be achieved in two ways. Forward overlap that is among photographs in the similar flight line and the other one is Lateral or side overlap among flight lines that are adjacent. Forward overlap is usually employed in stereo-viewing.

Stereoscopic Coverage:

A stereoscope measures the three dimensional view caused by a stereo pair. This kind of viewing allows the brain to create a 3-D image of the ground and helps in distinguishing altitude differences. Suitable overlap enables proper stereoscopic viewing.

Roll and Photo Numbers:

Each Aerial Photography Destin has a unique identifying number in accordance with the roll of the photo. This unique number allows detection of the photo in the archive of NAPL. It also helps in finding the metadata information like the date of photography, the altitude of the plane, the camera’s focal length and the climatic state of the region.

Flight Lines and Index Maps:

This is a graphical representation of the photograph that allows the NTS to detect the photos using geographical regions. The circles and the lines depict the photo centers and the number of photographs taken respectively.

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Created on Dec 31st 1969 18:00. Viewed 0 times.

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