Where Have They Been?

One of my interests is looking up N-numbers on the Federal Aviation Administration's (FAA) website.  I don't always know why I find this interesting but, once in a while when I see an airplane that has something unusual attached to it or an aircraft that I may not recognize, I save the N-number and look it up at http://registry.faa.gov/aircraftinquiry/NNum_Inquiry.aspx.  Sometimes, I look up aircraft and what they have been up to  by going to Flightaware.com and looking up their N-number or in the case of Keystone Aerial Surveys Inc. you can even search it by their ICAO callsign; thier callsign is Footprint (FTP).

Out of all the survey aircraft that I have looked up, I find that most of these are usually of the Cessna or Piper variety.  Occasionally I find that there are a few aircraft as in the case of Fugro Earth Data and Aerial Viewpoint, that use other various airplanes.  Generally, the aerial platform used tends to be a high wing single engine piston  aircraft or a light twin.  The one exception happens to be the Rockwell Aero Commander, which is a high wing piston twin.  High wing aircraft offer stability and a downward looking view. 

All of this may seem nosy, but one aspect that is made readily visible is who and what kinds of persons are hiring aerial survey firms.  I think of this as being competitive by using all available public knowledge to my benefit.

A Brief History of Aerial Cameras and Remote Sensing Technologies

Introduction

There are many ways to extract desired pieces of information about the earth's surface.  The method is generally dependent upon the tools available to the practitioner.  Without the necessary tools, the quality of information available to the practitioner is severely degraded.  This accuracy of the information is reliant upon the methods used to collect the data, and the reliable interpretation of this data along with other variable factors. As it is in many information gathering occupations, this same reasoning is applicable to aerial survey and remote sensing techniques.  From the early beginnings of balloon photography to the prolific use of aerial photography in World War II (WW II), the basic tool was the camera.  As the technology progressed, it evolved into even more advanced methods of gathering information.  These methods consist mostly of the aerial camera and satellites.  The way in which their evolution occurred, although similar, is decidedly different.

Development of the Aerial Camera and Remote Sensing

One of the earliest uses of the camera as an aerial tool was reconnaissance in WW I.  The camera as a tool of war gave observers a more accurate way to record the enemy’s positions and activities.  Originally, the cameras used for aerial surveillance were no different than cameras used in everyday life.  It was in World War I that cameras used for aerial survey applications became more sophisticated.  People began experimenting with different parts of the light spectrum to create better imagery.  Some of the advances and experiments during this era included layering different colored films to get different results, a three lens multispectral camera, camera stabilization and stereo-photos.
It wouldn’t be until after the war that a good camera for aerial survey would be created.  This advancement was due to an invention by Sherman Fairchild.  “Fairchild’s invention was to create a camera shutter sandwiched between lenses, thereby reducing the significant image distortion previously hampering aerial photography and mapping” (Sherman Fairchild: Totally Explained).  Fairchild sold his invention to the military and lost money on the deal.  Although he lost money, Fairchild would make other advances in aerial survey.  He eventually started Fairchild Aviation, and worked to create a better aerial survey platform.

Between the World Wars, aerial survey had to find a niche to remain viable.  In the United States, there were lots of farms and most farmers had no idea how much land they really had and what was useable.  Part of the Farm Credit Act of 1939 allotted for aerial mapping of these farms.  In fact the largest user of aerial mapping during this time period happened to be the U.S. government.  Out of all the governmental users the Tennessee Valley Authority (TVA) had the sole job of mapping the Tennessee Valley during the Great Depression.  By the end of the 1930’s the TVA had charted over a million acres and was one of the best mapped regions in the nation.  The knowledge and skills that were acquired by those who were employed in the aerial surveillance field would later be put to use in the Second World War.  Because of their great mapping expertise, the TVA would be assigned to map the coastal areas of the United States in order to prepare for a possible invasion.  Later on, the Army would use the TVA to map Nazi-occupied France. 

By the Second World War, aerial mapping had advanced to the point that it was no longer a daytime activity.  The general uses of aerial mapping in the Second World War, included mapping and damage assessment.  This was important in the fact that it gave military strategists insight on how well something was bombed in order to finish the mission or just go home.  In 1944 the Army would ask an MIT professor to design a flash strong enough to penetrate through the dark but not noticeable enough to be detected by enemy troops.  Harold E. Edgerton had already had the basic concept created by use of a strobe like device that would slow motion down.

In the 1950's President Eisenhower offered to trade aerial reconnaissance information between Russia and the United States.  However, the plan was met with opposition.  Russia declined the offer.  In response, Eisenhower made an agreement between the CIA and the US Air Force to contract with Lockheed Martin to design and produce an aircraft capable of high altitude aerial reconnaissance.  This brought about the creation of the U2.  As a result the first flight over the Soviet Union was on July 4, 1956.  The U2 had the capability to fly higher than any anti-aircraft mechanisms available at the time.  However, in 1960 Francis Gary Powers, a civilian pilot flying a U2 for the CIA was shot down, imprisoned and put on trial in the Soviet Union.

Later in the 1960's, some members of the United States Geological Survey (USGS) would propose to use satellites as a more cost effective solution for aerial surveillance applications.  The USGS was mostly interested in topography, although they acknowledged that there were a wide variety of applications for the technology.  Due in part to the capture of Francis Gary Powers, a satellite program was created in order to better apply surveillance to countries hostile to the United States.  This led to the creation of a number of satellite programs. Among these programs were the Corona and Landsat Satellite Programs, with the Corona Satellite Program being the first satellite program to be created.  The Corona satellite was equipped with two reels of cassette tape.  After the film was exposed to the cassette, the cassette was jettisoned and an aircraft recovered the jettisoned cassette in flight.  It is of interest to note that one Corona mission obtained more information than all of the U2 missions combined.  Some of the information obtained from this Corona mission included surface to air missile sites and other previously unknown air fields.  The Corona program lasted until 1972, when the United States Government began using the Landsat series satellites.

The Landsat satellites were used by the United States Geological Survey, the Department of the Interior, the Department of Defense, and many other governmental organizations.  Although the Corona satellite program was used mostly for military strategic purposes, the Landsat 1 Satellite was used for many non-military applications.  However the military still had access to more information than they did previously from the Corona series satellite.  The Landsat series satellites incorporated two different image sensors.  The most notable of the sensors was the MultiSpectral Scanner System (MSS).  The MSS would prove to be the workhorse of the Landsat Series satellites.  The MSS is important because it records multiple bands of spectral data.  The Landsat series of satellites had seven generations.  The seventh generation is still being used today and is scheduled for use up until 2012.  Advances from the Landsat series include thematic mapping, multispectral scanning and Return Beam Vidicon (RBV). 

One of the biggest mistakes in the Landsat program was privatization of the program.  Previous to the privatization of the Landsat program, imagery was relatively cheap to acquire and readily available.  However, when the Landsat program was privatized, the cost of imagery prices rose over 100%.  For this reason, many users of satellite technology opted for cheaper, lower grade imagery.  During this time, other companies such as Orbimage were trying to find a niche in the remote sensing market through selling satellite imagery.  Orbimage would later be acquired by GeoEye, which would become one of the largest providers of satellite imagery. 

To this date, aerial images acquired by satellite are almost as good as or better than surveys from an aerial platform.  However, the demand for survey from an aerial platform has not diminished to date.  For this reason, technological advances have been made in aerial survey cameras.  Some of these technological advancements include low distortion lenses, forward image motion compensation, the ability to use multiple sensing mechanisms in one unit, and most notably, the digital aerial camera.  "The hardware and software used to transform information from 2D digital imagery into 3D data has allowed the mapping process to become increasingly automated.  Leica Geosystems was the first company to introduce the large format digital camera, the ADS40, in the market in 2001.  The ADS40 produces images that are radiometrically and geometrically superior to images captured by conventional film cameras.  Vexcel, a company founded in 1985 and recently acquired by Microsoft, has also developed UltraCamD Digital Aerial Camera System that delivers large format aerial imagery.  Another such camera is Intergraph's Z/I Imaging DMC (Digital Mapping Camera)." (GIS Development)  Currently Leica has the most advanced camera.  Leica and Microsoft hold the greatest share of the digital aerial camera market. 

Conclusion

Aerial mapping and remote sensing technologies have advanced rapidly over the last eighty years.  The way in which we see the world now is far different than the way in which we used to see the world.  We are able to see on a thermal level, an ultraviolet level, infrared level, and are able to manipulate the information to suit our geographic needs.  Not only have advances to camera technology been important, but also advances to the aerial platforms have been made, including widespread use of satellite technology.  This technology is beneficial to a wide variety of people, from professionals needing accurate information about the surface, to the ordinary person needing directions to the coffee shop courtesy of Google Earth and Google Maps. 

How About a Piece of History

Go ahead and see for yourself.

http://news.google.com/newspapers?id=NGspAAAAIBAJ&sjid=MucDAAAAIBAJ&dq=aerial%20camera%20history&pg=791%2C737112

Aerial Triangulation as Presented by ASPRS

Farm Photography

I would like to thank the United States Department of Agriculture for today's material.  To visit their site just visit http://www.fsa.usda.gov/FSA/apfoapp?area=apfohome&subject=landing&topic=landing. I will also include this link in the useful sites index. The USDA provides an image library and a host of geospatial products.  I found it by googling aerial farm photography.  I decided to check the website out and found it to be informative.  In the meantime, here is a somewhat unrelated photo to entertain your eyes.  By the way, I like cows.