Where Am I at?

What a common question.  It has been my fortune many times in my life to not know where I am at.  With the advent of GPS, we are able to instantly know our exact location within plus or minus a certain parameter, but always close enough to get us to our destination.  As the technology improves, the factor of error becomes smaller.  In this beautiful age of gadgetry, we often rely on batteries to make the tools work.  This can be a very unfortunate issue if that is all we know how to do.  While I was in the military, we would often teach other soldiers how to use known landmarks, or their known position to help them find themselves.  This awesome method is known as triangulation.

Through triangulation, you are able to figure out based on the information available to you, where you are.  In the first example, you decide to drive some forest service roads.  You know that you just came from point "X" and you haven't been paying attention for a while.  After making a series of turns, you finally decide that you are lost.  Lucky for you, you know where you came from,

In a much simpler example, you are in a city.  In many US cities, the streets are at times laid in a grid and are labeled which direction they go.  If this is not the case, then it still doesn't matter.  Just by looking at your map, you can orient yourself based solely on the direction that you are walking.  This in itself, is a very basic form of triangulation.

Limitations in Satellite and Aerial Imagery Collection and Production

Introduction

It is inevitable that everyone has something to hide.  This includes even the most honest of people.  Whether it is that they cheated on their diet, to the candy bar that they stole when they were six, people have secrets that they either need or want to keep.  The rationale for keeping secrets isn’t always so clear or even logical.  Some of these secrets are exposed by taking the higher ground.  By taking the higher ground and using some form of aerial imagery, it is possible to expose some of these secrets, whether dirty or innocent.  In the case of the moonshine distiller or the marijuana grower, the reason to hide this secret is easy; getting caught is bad and cuts into their profit margin.  In the case of a state or government, the reasons may not always be so clear.  Generally the reasons usually have to do with national security, and the general welfare of the people in the care of the state.  However, the successful grower or distiller will find or create methods to conceal their labors, through methods of camouflage, misdirection and other creatively available methods.  Governments, in an attempt to conceal sensitive information, will also do the same.  It is herein that the question lies: what am really I looking at?

“Ground Truthing”

The easiest way to confirm an aerial photo is to physically visit the location, if at all possible.  This method of verification is loosely termed ground truthing. Ground truthing carries a couple of definitions.  However the basic idea of ground truthing is to verify an image is accurate in its depiction of the terrain and to verify that no anomalies have occurred.  In an extreme sense, ground truthing can also be used by strategic planners to ensure that a military asset is what it is meant to be.  An easy but good example of this occurred during World War II and the ensuing years after the war.  In order to trick the enemy, the allies would place dummy tanks complete with dummy tank tracks to fool the photo interpreter (see fig. 1).  

Fig. 1

The tools often used for this type of campaign generally relied upon deception, misdirection and camouflage.  In a non-military environment, a good reason to ground truth an image is that an image may contain some unknown variable.  However, without visiting the site, the image interpreter may be unable to accurately discern certain features such as a house that may be hidden within a grove of trees.  In ground truthing, there also may be errors in the imagery.  Some of these errors can be classified as errors of omission or commission.  An error of omission may occur when an object is not classified, even though there is a classification for that object.  For instance, though a manhole may be visible on an aerial, the interpreter of the aerial image may fail to classify it as a manhole.  An error of commission may occur when an object becomes classified as another object that it is really not.  An example of this would be an asphalt road labeled as a train track. (Wikipedia; Ground Truth).  It is important to ground truth because remote imagery has many limitations.

Limitations in Collection and Production

In aerial mapping and remote sensing, there are many limitations which can affect the final outcome of the product.  Some of these limitations are directly related to the sensor, the airborne platform, the environment, the interpreter/user of the information, and multiple other factors such as cost.  In order to mitigate these effects, there are a variety of solutions which may be employed. 

The biggest cause for error is human.  Being human is in itself a limitation that enables us to do or not do certain tasks well.  It is for this reason that one of the limitations if imagery is human error.  In classifying objects in an image, the image is only as good as the interpreter.  As discussed previously, this is one of many reasons why we ground truth.  Although we are human and this is a limitation in itself, we are also limited by how well we understand the technology, our ability to exploit the technology, and the ability of the technology to adequately perform the required task.

One of the most obvious limitations in acquiring imagery is the weather.  Weather factors such as cloud cover, fog or snow may make it difficult to obtain quality images for both satellites and aerial platforms.  Additionally, weather factors such as wind may make it difficult for an aircraft to fly within tolerance of the planned flight path required to obtain quality data.  Even though weather has its limiting factors, there are ways to overcome this.  Sensors attached to a space based platform are rarely affected by weather. Radar sensors such as Synthetic Aperture Radar (SAR) and side looking airborne radar (SLAR) have the ability to penetrate clouds.   In general, space based platforms are able to outperform the aerial platform as the space platform is not weather dependant.

Trees and other ground features may also create limitations in obtaining quality imagery data.  Trees and shadows from trees and other objects may make it difficult to see objects on the ground.  As discussed previously, radar sensors have the ability to penetrate clouds.  Unfortunately, radar sensors consistently fail to penetrate through dense objects such as forests.  This makes it difficult to acquire good data about ground topography and ground features from radar in forested areas.   The best way to verify objects on the ground is through ground truthing and supplementary ground survey.

When acquiring aerial imagery, the cost and time of travel must also be taken into account.  It is possible for some companies to affix multiple sensors at one time.  As technology becomes better, some sensors have incorporated multiple modes of acquisition.  An example of this would be an operator such as Keystone aerial surveys out of North Philadelphia (KPNE) who use the UltracamX.  “The UltraCamX is a multispectral imaging sensor capable of capturing panchromatic, red, green, blue, and near infrared data simultaneously” by incorporating multiple sensors, the operator has the ability to better serve the client through faster turnaround times. 

Another consideration is the need to set up control points on the ground for aerial surveying.  These control points on the ground provide a way to correlate the images collected with the ground grid coordinates and elevations.  Setting up control points is also a form of ground truthing.  Setting up ground control points is a project cost and requires additional time and coordination.  It requires a survey crew to go out and set up panels, and survey the panels location.  A process known as analytical triangulation is used to correlate the ground control points with the aerial data.  In the article titled “From the Ground Up: Direct Georeferencing in Aerial Photography” by Mark E. Meade, the author states that one way to overcome the need to set up control points is to use Airborne Global Positioning Systems (ABGPS).    By using ABGPS, it is possible to know the aircrafts position relative to the earth at all times.  With the advent of Airborne Global Positioning Systems (ABGPS), the number of control points required for a project is greatly reduced, thus saving time and money.

There are different advantages and disadvantages to the use of satellites versus an aerial platform.  Satellites are generally more able to acquire large areas with relative ease, whereas an airplane may require several flight lines and multiple control points in which to gather the information.  Aerial platform radar systems tend to be a good method to map an area quickly and efficiently with a relatively lower cost, because the flight line tends to be wider and would require fewer flight lines flown In this same way that radars are used on aircraft, this is a sensor that also translates to a space-borne platform. 

A satellite can often produce the same image that an aerial mission would acquire, but would be at a greater cost.  For small projects, satellite may not be cost competitive with the aerial platform.  For large projects, the time saving benefits of using satellite might outweigh the additional cost.

Let’s just propose an example.  In this example I need to do a noise abatement study because commercial traffic at Prescott Love Field (KPRC) in the last two years has increased by 15%.  The surrounding neighbors keep calling the City of Prescott airport manager and complaining about how noisy traffic at the airport has become and how they can no longer sleep at night.  It is bad business to drive this traffic away, since this is the very traffic that is bringing money in for the city.  In an effort to solve this problem, the city manager along with various other authorities would have to come up with a way to move the traffic away from the housing development.  This would keep the airport manager employed and the neighbors happy.  In order to effectuate this plan however, an aerial image of some sort must be acquired in order to show any new development that may have taken place.  The City must minimize the cost required to perform this study. 

Aerial imagery of this nature is readily available through various vendors.  One of the more prominent online vendors, mapmart of mapmart.com prices imagery with a two foot resolution for satellite at $822.  This same area can be acquired for $567 if you desire imagery from an airborne flight.  Although this is a savings of $255 (even for large companies that is a decent savings), the imagery is slightly outdated (See Fig. 4 below).

Fig. 4

It would likely cost even more money to have aerial photographs of this area taken specifically for this project.  The problem is that the City must balance the cost of the data they need against the quality of the data.  If the Airport Manager believes that growth to the area surrounding the airport has been minimal over the few years, the older data may be acceptable.  If the Airport Manager is unsure of how much growth has occurred recently, or if recent growth has been substantial, the manager may choose to have aerial imagery collected specifically for this project, despite the increased cost.

Conclusion

Though there are limitations to all forms of imagery data collection, satellites generally seem to have fewer limitations.  There are still applications in which data from an aerial platform may be preferable to data from a satellite.  Because both forms of imagery are imperfect, the only way to know for sure what is being seen is to ground truth the data.  Through real time verification, we can ascertain the properties of hidden marijuana plants or mislabeled tanks with the all inclusive fake tank tracks.


For a complete works cited please leave a comment.

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.

GIS is one of the best ways to get information...

History of Aerial Photography Platforms and their Uses

Introduction

Aerial Photography, Aerial Mapping, Aerial Survey, Remote Sensing or however it is called serves many different purposes.  The basic tools required to carry out an aerial photography mission consist of an aerial platform and a way to capture the imagery.  These tools usually consist of an airplane, and a camera.  Although airplanes are the most commonly used platform, there are other methods used to achieve basically the same result.  Some of these other methods include balloons, kites, rockets, airplanes, helicopters, satellites and multiple other unusual creations.  Many of these methods were creative solutions to a challenging problem, when airplanes and helicopters were not available.  Today, it is a lot easier to fly a mission with a helicopter or a fixed wing aircraft.  Using a fixed wing platform allows for a more thorough picture and has the ability to deliver higher quality images. 
When aerial photography was in its infancy, the tools used at the time were large bulky cameras and balloons.  In fact, the cameras were actually and are still called large format cameras.  Many of these cameras used a variety of plates that required a cocktail of toxic chemicals in a wet or dry format.  Often these plates were likely to be exposed to contaminants that would ruin the photo.  Throughout the development of camera technology, cameras became progressively smaller, lighter, easier to use, and photos became easier to develop.  Even though aerial reconnaissance was a high priority in World War One (WW I), it wasn’t until after the war that a camera suitable for aerial photography would be invented.  It was Sherman Fairchild’s intention “to create a camera shutter sandwiched between lenses, thereby reducing the significant image distortion previously hampering aerial photography and mapping” (Wikipedia; Sherman Fairchild).  Aerial mapping has come a long way since the French incarnation of a balloon and a camera and in many ways it is WW I is where aerial mapping really began to mature.

Balloons as a Platform
 
Throughout the late 1800’s many attempts at aerial photography were made, and largely failed.  Of the many forms of aerial photography that exist, the balloon as a platform was one of the first.  Although the photographs no longer exist, some of the first aerial images were captured by a Frenchman named Gaspard-Félix Tournachon more commonly known as Nadar.  Because he was using the wet process, Nadar often had difficulties in getting the images to develop correctly.  The wet plates he used in the camera would become contaminated with the hydrogen sulfides emitted from his balloon. This contamination caused the plates to fog.  Though most of Nadar’s aerial photography experiments failed, he did succeed a number of times, albeit by accident.  In an attempt to conserve fuel, Nadar closed off the vent to the balloon and the balloon released fewer sulfides.  By closing the vent, this allowed Nadar’s photos to be less obscured and provided for greater clarity in the photographic details.  Photographic evidence of his success has unfortunately been lost over time. 
As sad as it is that Nadar’s photographs do not currently exist, the first known aerial photos still in existence were taken only a few years later by James Wallace Black. Like Nadar, Black had his fair share of problems.  In an effort to make the balloon more stable, Black’s balloon was tethered to the ground.  This proved difficult in that the wind made the photography hard.  By this time many photographers had converted from wet plate technology to dry plate processes.  Even though technology had moved from the wet plate to the dry plate, photography was still a slow moving art in the sense that if there was a lot of movement then the exposure wouldn’t turn out very well. 
Not long after Black had shown how useful balloons could be, “balloons were used for surveillance and reconnaissance during the Civil War for both sides, [with] the Union side invest[ing] heavily in their development. The ability to locate troops and assess their numbers quickly became a very important capability, but it is not known if a photograph from a balloon was ever taken because to date no vertical or oblique aerial photography captured by balloons from the Civil War period have been found” (US War Balloon Corps.).  This trend to use balloons for military use gave the advantage of high ground.  In fact, “the French had first used balloons for reconnaissance during the Napoleonic wars and later in the Franco-Prussian War. So aerial reconnaissance was a strategy that was familiar to them…” (Century of Flight). 

Kite Aerial Photography

Even as far back as Greek mythology will take us, mankind has been seeking ways to fly.  This innate desire to harness the wind is manifested as far back as the kite.  Probably one of the best known Chinese inventions, the kite has rendered itself not only as an item of beauty, but also an item of utility.  One of the challenges that faces kite aerial photography (KAP) is the ability to make a camera airborne and acquiring a stable image.  M. Arthur Batut, one of the earliest practitioners of KAP accomplished this by attaching a camera directly to the kite.  “The camera attached directly to the kite, had an altimeter that encoded the exposure altitude on the film allowing scaling of the image. A slow burning fuse, responding to a rubber band-driven device, actuated the shutter within a few minutes after the kite was launched. A small flag dropped once the shutter was released to indicate that it was time to bring down the kite“(History of Remote Sensing, Aerial Photography).  Other KAP practitioners developed their own methods for capturing aerial images.  This generally included stringing kites together in series, or by using a combination of kites and balloons.  Interestingly enough it is from KAP, where to this day, George R. Lawrence is credited with capturing some of the largest aerial photos to date.  Lawrence’s technique in fact used multiple kites strung together in combination with a large format camera.  Lawrence’s photos are so large in that he designed a curved plate to provide a larger panoramic view of San Francisco.  It is appropriate that the photos were large as a matter of necessity, the cause being a large fire and earthquake that had devastated San Francisco in 1906.  Although there were many others using kites to capture aerial photography, the methods were generally all about the same.  The largest differences lie in the way in which the photographer was able to capture the image.  As was previously stated cameras were bulky, heavy pieces of equipment.  Therefore the photographer had to either create a kite large and stable enough to effectuate good photography or as is the case today, camera technology had to improve.  From a historical perspective, the history of KAP has yet to find an ending.  Still to this day amateurs and enthusiast alike still attach cameras to kites in an effort to produce beautiful aerial photographs.  As a general rule and because of its limitations, it is no longer a practical method for capturing aerial imagery.  KAP shows us that anything is possible, and provides a small form method for capturing aerial imagery.

Pigeon Cameras

As technology improved, cameras became smaller. This allowed for the use of smaller aerial platforms. It no longer becomes necessary to airlift a camera in a balloon or on a kite.  One innovation that has no other place than its own is pigeon photography. “In 1903, Julius Neubranner, [a] photography enthusiast, designed and patented a breast-mounted aerial camera for carrier pigeons. Weighing only 70 grams the camera took automatic exposures at 30-second intervals along the flight line flown by a pigeon” (History of Remote Sensing, Aerial Photography). In 1909 Neubranner had the opportunity to showcase his fleet of pigeons at the Dresden International Photographic Exhibition.  To most the photos proved a novelty and were used as postcards.  Even though the pigeons were not always reliable in their flight paths, it is of importance to note that there needed to be a time interval.  This is true for a simple reason; physics.  In flight it is crucial to know your time, speed and distance.  If you have two of the three you can figure out the third part of the equation.  For example: if you have a speed of 30 knots with a distance of 10 nautical miles you can determine the amount of time it would take you to travel 10 nautical miles at a speed of 30 knots.  For purposes of reference, the answer is that it costs you about 20 minutes of your time.  When the speed is known it is easier to calculate how many images should be acquired over a certain distance in order to get a complete picture.  Although more of a novelty and like kite aerial photography, pigeon photography goes to show that almost any airborne item can serve as a platform.

Fixed Wing Platforms

As technology evolved so did the platforms used to capture aerial images.  Balloons had been around since the late 1700’s and man had been trying to achieve flight for many years before a successful attempt was made.  The first winged flight was not actually an airplane but a glider designed by a German named Otto Lilienthal. Before the Wright brothers invention of the airplane there had been many different attempts at producing other incarnations of vehicles that were heavier than air.  There were even a few successful attempts that almost made it before the Wright brothers.  It is for this reason that the Wright brothers are also credited with many firsts.  Among the many firsts that the Wright brothers can claim include the first aviation fatality, the first aerial recording and a host of other accidental firsts.  Another first that still exists to this day is the way airplanes are sold.  In order to buy an airplane the salesman will put the airplane on display and a prospective buyer can ask for the opportunity to demo the airplane.  It is in this fashion that “on April 24, 1909, Wilbur Wright was giving exhibition flights in Italy, and on one of these flights he carried a passenger who took motion pictures of the military field at Centocelli, near Rome” (Manual of Aerial Survey).  
If there was ever a place or a time where aerial photography would flourish, it would be WW I.  In the history of aviation, aircraft made it easier and faster to trespass into enemy territory and leave quickly.  The chief of the German General Staff, General Werner von Fritsch, once stated, “The nation with the best photoreconnaissance will win the war” (History of Remote Sensing, Aerial Photography). Having an aerial presence, made it easier to gather information and to relay it back to the command post.  Reconnaissance missions usually required an observer and a pilot. Most commonly if an observer were to relay messages, the observer would use a variety of methods.  Some of these methods included hand signals, message drops, or sketches.  It quickly became apparent that by using a camera the observer would have more accurate information.  This proved to be a very efficient way to gather information and soon it became a common practice. “By the end of WW I, Camera technology had flourished.  “The quality of cameras had improved so much by the end of the war that photographs taken at 15,000 feet (4,572 meters) could be blown up to show footprints in the mud” (Century of Flight; Aviation During World War One).

By WW II, Germany was the most prolific user of aerial photography.  Its use was so abundant that it was used for damage assessment, and mapping.  In fact, some speculate that one reason Germany lost the war is because they stopped using aerial photography.  Use of aerial photography was also important to the Allied forces. In 1945, Admiral J. F. Turner, Commander of American Amphibious Forces in the Pacific, stated that, “Photographic reconnaissance has been our main source of intelligence in the Pacific. Its importance cannot be overemphasized.” 

It was in WW II in which mapping became an important part of America.  It is because of these wars that remote sensing and aerial mapping technology developed so rapidly.

Conclusion

Man has always wanted to be free from the bonds of earth.  Man has always wanted to record his surroundings.  It is in these aspects that aerial surveillance comes to fruition.  Without these freedoms we can neither record nor visualize what we need to know.  It has been a valuable resource to those who use it, and continues to be of value today.  Even though mainly in the past it has been a resource mostly available to military planners, the technology has and will continue to spill over into the civil sector.  This is important because there are many useful aspects to aerial surveillance and many different ways to record the information.  It is from this that we are able to gain the big picture in order to more accurately define the boundaries of our world.  It is in fact, with these methods that the boundaries grow ever smaller.  It is in this way that man frees himself from the bonds of the earth, and it is in this way that man records what he has just freed himself from.

Pioneers of Aerial Mapping

How about a nice youtube video courtesy of ASPRS.  For more information about ASPRS check out the link to your right.

What is to Come

I think for a while I will switch gears and focus on the history of aerial photography in it's early stages up till about the end of WWII.  Pigeon photography fascinates me and so like subjects will be the focus for a short while.  

How to use pidgeons in aerial photography.

1. Strap a camera on to a pigeon.

2. Make sure you know it's flight path and speed.

3. Set camera to take pictures at regular intervals.

Well, if only it were that easy.  Amazingly enough it has been done before.  Generally when we think of an aerial platform, we assume it is going to be a helicopter, UAV, or some form of fixed wing aircraft.  Historically speaking, aerial photography has been around as long as Wilbur and Orville Wright and even longer.  One of the methods used was actually pigeons.  In fact "in 1903, Dr. Julius Neubronner patented a miniature pigeon camera activated by a timing mechanism. Equipped with the cameras, the pigeons photographed a castle in Kronberg, Germany, around 1908" (http://www.nasm.si.edu/exhibitions/lae/SCRIPT/be_first2.htm).

The basics of this would involve knowing the pigeons flight path, the speed at which the pidgeon flies, and maybe the altitude of the bird.  As was demonstrated, it would then be possible to take photos at certain time intervals.  I found a lot of info just by googling pigeon aerial photography.  Give it a look, it is quite interesting.

Company Profile: Surdex

Again, as stated in the previous post Surdex is currently hiring, and for this reason Surdex gets a company profile.

History: http://www.surdex.com/CompanyHistory.aspx
Aircraft: Cessna TU206F (1), Cessna 335 (1), Cessna 404 (1), Cessna 441 (3)
Types of Services: Aerial Photography, Orthophotography, Topographical and planimetric maps, GIS and Lidar.
Major Projects: http://www.surdex.com/RecentProjects.aspx


Look it up and see what Surdex is about.

Surdex is Hiring

The link is from USpilot.com and reads:

Details
Title  Pilot – Aerial Photography

Description    Surdex Corporation, a St. Louis Missouri based, leading nation-wide provider of
aerial photography, and mapping services for federal, state, local governments, and private
industry, is seeking experienced pilots. Preference given to experienced high-altitude Turbine
Photo Pilots with the USDA NAIP program. Candidate must possess at a minimum, COM/INST/MEL
certificate, 1,000 hours PIC, 300 hours multi. Surdex operates C-441, C-404, C-340 & C-206.
Out-of-town travel and deployment required. Competitive pay and benefits. Applications accepted
only via e-mailed cover letter and resume including relevant qualifications and compensation
requirements to: Human Resources, Surdex Corporation, 520 Spirit of St. Louis Blvd.,
Chesterfield, MO 63005 or e-mail to: hr@surdex.com. Visit www.surdex.com EOE/M/F/D/V

for more information sign up for a free account at uspilot.com.  I also recommend checking out the Surdex website. The link can be found at the right in the companies worth noting section or at http://www.surdex.com/positionsmoredetails.aspx?id=80.  I would get it while it is hot.