Aerial photography has been around since
Gaspard-Felix Tournachon started taking snaps from the basket of his hot air
balloon in 1858. Since then, the technology has been refined to deliver complex
images of land masses, settlements and military installations. Have a look
through these five fascinating facts about the technology – its history, its
application and its equipment – to get a handle on the most advance form of
photography on (and above) the earth!
World War I was fought with aerial maps
During the First World War, aerial
photography was used to create or correct maps of enemy territory. The first
protracted use of aerial photography for military uses was conducted by General
Allenby and a Royal Australian Air Force squadron based in the UK. His five
photographers flew over enemy lines in Turkish airspace, escorted by fighter
planes, to carry out a photographic survey that enabled Allenby to correct
vital tactical maps.
Robot helicopters take aerial snaps
One of the most common machines used for
surveying and aerial photography is the Coptercam, or Octocopter. The
Octocopter is a flying robot with a camera system mounted in its belly, powered
and steered by eight rotary blades (hence the name). It is used to survey land
from Australian airspace, and has recently been put into service surveying the
damage done by extreme weather systems.
In the US, it’s legal to spy on people using aerial
photography
In America, airspace is technically public.
In US law, if you can see something from a public space then you are not
spying. Because of this, it is perfectly legal to use aerial cameras to capture
people doing things that cannot be seen from the ground. This includes the
documentation of things that are happening in the boundaries of private
property – which may not be documented from the streets.
Aerial cameras have been taking giant pictures for
decades
In the 1930s, Sherman Fairchild
perfected his design for an aircraft mounted camera system capable of taking a
single image that accurately showed 225 square miles of land. Before the end of
the decade, Fairchild had increased the accuracy of his cameras to 600 square
miles per exposure. The advancement of the technology started by Fairchild is
the basis for modern photographic mapping.
Aerial photography forms the basis for modern maps
Photogrammetry (the process by which
geometrical relationships are deduced from aerial photographs) forms the basis
of much modern mapping. Highly detailed aerial photographs are taken, which are
then “translated” into cartographs (maps) using the principles of projective
geometry. In its simplest form, projective geometry involves measuring the
distance between two points on the map, then factoring in the known geographic
coordinates of those points to get the proper cartographic representation.
Photogrammetry requires range data to
work properly. This is often obtained through LiDAR (Light Detection and
Ranging) – a relative of RaDAR (Radio Detection and Ranging) in which light
pulses are measured to determine the distances between objects. For more information about
aerial mapping, LiDAR and photogrammetry, follow the link.
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