Aerial Photography

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Aerial Photography

Aerial Photography is the process of taking photographs of the earth’s surface from the air with the help of camera mounted on helicopter, rocket, aeroplane or any other similar vehicle.

 

History of Aerial Photography

 

Historical aerial photography refers to various stages of progress made in the field of aerial photography. The art of taking aerial view photos started with attaching cameras to kites. This was known as kite aerial photography. French photographer and balloonist, Nadar first practiced aerial photography in 1858. Fres Zinn and other aviators like him expanded the use of aerial photography for military purposes during the First World War. The French units are known to have printed as many as 10,000 photographs a night during the periods of peak activity during the war that lasted from 1918 to 1922. Since then special cameras are mounted on various airborne vehicles to take aerial photographs. Digital aerial photography refers to the use of digital camera for the purpose of taking aerial photos.

Aerial Photography Applications

In contemporary times aerial photography finds use in many fields such as cartography, environmental studies, archeological studies, town planning, urban planning and many other fields. The use of aerial photography in GIS is noteworthy. It is an excellent source to provide spatial data from the same location at periodic time intervals. The images obtained by aerial photography have radial distortion, which can be easily corrected in GIS. The applications, where typical use of the aerial photography integrated with GIS is made, include land-use surveys and habitat analysis. Aerial photography business is an upcoming profitable arena in view of the increasing commercial fields that use aerial photographs in various stages of business planning and development.

Advantages of Aerial Photography

Aerial Photography has the following advantages over ground-based observations:

Aerial Photography gives an enhanced vantage point. Aerial Photography captures action on the ground. The events are recorded permanently Aerial Photography offers a broader spectral sensitivity than the human eye. Aerial Photography is superior to the ground-based sensing methods as it has better spatial resolution and geometric fidelity.

Types of Aerial Photographs

 

Aerial Photographs are of two types:

• Black and White Aerial Photos
• Color Aerial Photos

Elements of Aerial Photography Interpretation

 

The basic elements of interpreting Aerial Photographs are:

• Tone (also called Hue or Color) — Tone refers to the relative brightness or color of elements on a photograph. It is the most basic of the interpretive elements because without tonal differences none of the other elements could be distinguished.
• Size — The size of objects must be considered in the context of the scale of a photograph. The scale will help you determine if an object is a stock pond or a lake.
• Shape — refers to the general outline of objects. Regular geometric shapes are usually indicators of human presence and use. Some objects can be identified almost solely on the basis of their shapes like:
  1. The Pentagon Building
  2. (American) football fields
  3. Cloverleaf highway interchanges
• Texture — The impression of “smoothness” or “roughness” of image features is caused by the frequency of change of tone in photographs. It is produced by a set of features too small to identify individually. Grass, cement, and water generally appear “smooth”, while a forest canopy may appear “rough”.
• Pattern (spatial arrangement) — The patterns formed by objects in a photo can be diagnostic. Consider the difference between (1) the random pattern formed by an unmanaged area of trees and (2) the evenly spaced rows formed by an orchard.
• Shadow — Shadows aid interpreters in determining the height of objects in aerial photographs. However, they also obscure objects lying within them.
• Site — refers to topographic or geographic location. This characteristic of photographs is especially important in identifying vegetation types and landforms.
• Association — Some objects are always found in association with other objects. The context of an object can provide insight into what it is. For instance, a nuclear power plant is not (generally) going to be found in the midst of single-family housing.

The major companies of the world, according to their continent, working in this field are enlisted below:

• North America
• South America
• Europe
• Asia
• Australia
• Africa