The Connecticut State Library houses the 1934 aerial photography collection. Below are excerpts from the Connecticut State Library website about the history of the 1934 aerial photos and their efforts to preserve and provide access to the photographs. The Connecticut State Library and the UConn Map and Geographic Information Center (MAGIC), part of UConn Libraries, have worked together to provide the aerial photographs as one mosaic that can be accessed online and with other geographic data. A long list of contributors are listed on the MAGIC website. Thanks to all for making this dataset accessible.
There are multiple ways to view and download the scanned 1934 aerial photographs.
FAQ: Why doesn’t the 1934 mosaic align with more recent aerial imagery?
The 1934 aerial imagery mosaic was created by UConn MAGIC. Each tile was georeferenced using a GIS. Georeferencing is the process of giving coordinates to a dataset, in this case, a scan of the original 1934 aerial photographs. Georeferencing involves identifying ground control points on each 1934 scanned image and comparing the points to a "truth" dataset in order to tie them together. Students did this work to enable the creation of a true mosaic - a single, statewide raster of 1934 aerials. This is a tremendous accomplishment but is not perfect for multiple reasons. The accuracy can vary considerably between tiles are areas.
1. Technology
1934 camera and airplane technology is quite different than today, nearly 100 years later. The airplanes twist and tilt and can cause distortion and warping. The cameras were not as sophisticated and resulted in inconsistencies between tiles and days of flying.
2. Control Points
Finding control points for each scanned tile can be a real challenge. Each control point needs to be on a spot that is visible and doesn't change over time, like shorelines. Ideally, multiple control points are spread across the tile. Some areas have experienced extensive land cover change and there are virtually no areas that are consistent between 1934 and today. Forested areas are also difficult as obvious, unchanging land marks are hard to come by.
3. Mosaic
When a true mosaic is created in a GIS, the GIS professional and the software do their best to ensure that seams line up and seam lines are not visible. When seams line up, linear features like a road are straight across many tiles. Shen seams are not visible, any changes in brightness/darkness, seasons, or other factors are not obvious. A mosaic can only be as good as it's input data tiles AND it's georeferencing results. For the 1934 mosaic, imperfections from both the technology and control points will be evident in the mosaic.
FAQ: Is there an effort to improve the 1934 mosaic?
Yes! We are glad you asked! There are two ways that we are working on improving the mosaic.
Improve georeferencing
Through several research projects, UConn CLEAR is revisiting the georeferencing of individual 1934 tiles to improve their accuracy. Each tile is carefully checked by UConn CLEAR's geospatial team. We are also working with geospatial partners who have done the work for specific areas. To date, this includes MetroCOG and the Connecticut coast through another project.
Virtual mosaic
Instead of creating a true mosaic where all tiles are actually merged together, the team is creating a virtual mosaic. A virtual mosaic means that each tile remains independent but is viewed in relation to other tiles. One benefit is that it can slowly be expanded and improved without redoing all of the work. Another benefit is that one tiles brightness/darkness does not have to influence it's neighbor, resulting in more visual detail. The 1934 tiles have a lot of overlap, and the virtual mosaic allows us to display higher quality tiles on top of poorer quality tiles.
We will post the link to a service of the improved tiles when it is ready. Please check back and/or let us know you are interested by emailing CLEAR, see footer.
Viewers
Neighborhood Change in Connecticut, 1934 to Present. UConn MAGIC hosts an interactive map that compares the 1934 mosaic to current Google maps.
CT ECO Aerial Imagery Viewer. The 1934 Mosaic is now part of the Aerial Imagery Viewer which contains all of Connecticut's statewide, digital aerial imagery. The layer list and tools like swipe and transparency allow for comparison of different imagery datasets.
GIS Services
MAGIC WMS Service. MAGIC provides the 1934 Mosaic as a WMS service (no secure connection).
CT ECO Image Service. CT ECO now provides the 1934 Mosaic is as an image and WMS service. The Service can be viewed online as well as opened in online and desktop GIS software.
Download
UConn MAGIC Air Photo Archive. Use the layer list to select the desired dataset (here, AirPhoto 1934 CT) to see the centerpoints of all photos. Each centerpoint links to downloads in jp2, pdf and tif formats. The downloaded files are not georeferenced.
CT State Library. Use the town map locater to find the correct tile for a location. The download files are not georeferenced.
The 1934 Aerial Survey Project: a Tool for State Planning
Source: CT State Library website
Governor Wilbur L. Cross recommended an aerial survey of the entire state of Connecticut to the State Planning Board in 1933. The governor and the board saw such a survey as an essential tool in planning for the state’s future. Dr. Charles G. Chakerian, director of the Board, said "The Water, Tax, Health, Highway and other departments had wanted one for years." (Hartford Daily Courant Mar. 31, 1935) The survey would be the first government sponsored aerial survey of an entire state. (The Institute of Geographical Exploration at Harvard University conducted an earlier survey of Massachusetts, the first of an entire state. These photographs can not be found today.)
Fairchild Aerial Surveys, Inc. of New York City, an innovator in aerial photography and aviation, conducted the aerial photography for Connecticut’s survey. The result was thousands of individual photographs, which were pieced together to make a massive mosaic view of the state.
Governor Cross organized the State Planning Board in late 1933 and the first board statement was issued on January 8, 1934. The Planning Board was originally composed of:
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- William L. Slate, Chairman (Director of the State Agricultural Experiment Station)
- Joseph W. Alsop (Public Utilities Commission)
- Austin F. Hawes (State Department of Forests and Parks)
- William F. Ladd (State Militia)
- John A. MacDonald (State Highway Department)
- Allen W. Manchester (Connecticut State College)
- Daniel S. Sanford (Fairfield County Planning Association)
- Sanford H. Wadhams (State Water Commission)
- Charles G. Chakerian, Director- a prominent writer on social and religious issues, then a research fellow at Yale University
Civil works planning was a national initiative through the National Planning Board of the Federal Emergency Administration. The effort was to identify worthwhile public works projects that could be funded with federal money. The National Board delegated to a regional board for New Jersey, New York and Connecticut. The state board reported to both. The money for Connecticut’s planning board came through the Civil Works Administration and the Public Works Administration.
The purpose of the planning board was to coordinate and integrate information pertaining to growth and development of the State. They collected information, data and maps from across departmental lines and made the information available to all. There were several projects initiated by the board relating to water quality, forests, highways, population demographics and zoning. An aerial map of the State was considered “the most essential single step for our state-wide data.” (Connecticut State Planning Board, Statement #9, April 4, 1934. CSL call number: ConnDoc P693 st) The aerial survey would give valuable information to many state departments.
1934 Aerial Photography
"Two men in a cabin plane circled around in a cloudless sky. They flew, at 100 miles an hour, up the state. Every 25 seconds the photographer took a picture of three and one quarter miles." (Hartford Daily Courant Mar. 31, 1935)
The planning for the aerial survey had already begun before January 1934. Fairchild Aerial Surveys, Inc. was chosen to conduct the photography and photographing of a photo mosaic. Fairchild was perhaps the only company capable of doing a survey of a complete state at this time. The company was named after its founder, Sherman M. Fairchild. He was a restless scientific genius that came from a wealthy family. In consequence, he had means to form companies around his inventions. After the First World War, he formed a company to manufacture his revolutionary aerial survey camera. Fairchild Aerial Surveys, Inc. was formed in 1922 to exploit the innovations of the camera. He then formed a company to build airplanes with enclosed cabins and single wings to expedite aerial surveys.
In the 1920s, the Fairchild Aerial Survey company “constantly lobbied Governor John Trumbull to contract for a survey. After all, Trumbull could be called, ‘The Aviation Governor,’ because … he was an active pilot. When Lindberg came to Hartford … after crossing the Atlantic, Trumbull flew his plane in to Brainard Airport to meet him” (memo from State Archivist Mark Jones to State Librarian, Ken Wiggin, dated 6/25/99). But at that time, no one state agency could pay for an aerial survey. The project waited till the State Planning Board coordinated the effort.
Four airplanes did the aerial photography for the Connecticut survey in March and April 1934. The early spring months were chosen so as to be free of snow cover yet be before the sprouting of leaves on trees. Fairchild owned three of the airplanes, probably Fairchild manufactured FC-2 cabin airplanes. It had a heated, enclosed cabin so that pilot and photographer could endure long hours in the air. It was a monoplane with the wing extending from the top of the airplane to have an unobstructed downward view. The wings also folded for transport by railroad to survey locations. The fourth airplane belonged to the Connecticut National Guard, 43rd Air Division, 118th Observation Squadron. This was a Douglas O-38E two-seat, open cockpit observation biplane that was standard with the Air Corps at the time.
The pilots for the photography were:
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- S. Reiss- Fairchild Aerial Surveys, Inc.
- Lt. Charles L. Wright-118th Observation Squadron (lived in New Britain in 1930 and was perhaps a solderer for Landers, Frery and Clark, manufacturing electric appliances.)
- William Knox- for 118th Observation Squadron
- Stanley Ferguson- for 118th Observation Squadron
The photographers, all from Fairchild, were Sidney Bonick (project supervisor), Harry Holstrom, Thomas Noble and T. Domins.
The camera used was a Fairchild K-3 aerial survey camera with a 9.5” focal length, F4.5 lens and a haze-reducing filter. The camera was mounted on a frame and had an electric motor advance and a timing device to automatically shoot pictures. The view-finder had two inked lines to aim for current exposure and overlap of image. The film was 9 inches wide and 75 feet long rolled in canisters. There were 100 exposures per roll. The exposures were 7.5” x 9” each. The scale was 1”:1,200’. (The prints in the collection of the State Library have the same scale.)
The survey fights were flown at 11,400 feet, as level as the pilot could fly. The speed of the airplane was kept at 100 miles per hour. The photography was taken at vertical (90 degrees.) The exposures were taken at a rate to have a 50% overlap. That is, each photograph would have half of the previous exposure and half of the subsequent exposure. Photographs were taken in flight lines of 16 to 20 miles that were plotted from topographic maps. The air crews could take as many as four rolls of film in a day of filming.
The aerial photography was done on good weather days in March and April 1934. Optimum time of day for photography was from 10 AM until 2 PM. A total of 153 flying hours were required for the four airplanes to cover the 5,004 square miles of the state.
There were 10,484 exposures made in the state survey of which many were unusable because of missed orientation, clouds or reflections. The film was shipped to Fairchild Aerial Surveys Inc. for developing and printing. At least two sets of prints were shipped back to Hartford: one to the Connecticut State Library and one to be used in the creation of the mosaic map. Copy photographs were requested from the State Library almost immediately after arrival. Copy photographs were ordered from Fairchild, who housed the negatives.
Fairchild also provided index sheets to the photographs. The 33 index sheets are reproductions of the 1895 U.S. Geological Survey topographic maps with boxes inked in to locate particular photographs. The photograph number was printed inside the box. A photograph number in a circle identified photographs not printed. Approximately every other photograph was indexed perhaps for reasons of space on the sheets. The State Library enlarged the index sheets to the scale of the U.S. Geological Survey topographic maps.
Report on the State Library Scanning Projects: Aerial Survey Photos of Connecticut
Source: CT State Library website
Providing access to the aerial photographs while ensuring their preservation has been a goal at the Connecticut State Library since the first statewide aerial survey was delivered in 1934. Researchers have always used the individual aerial photographs frequently: 27% of all items retrieved from secured collections in 2001-2002 were the prints from the 1934 aerial survey.
1934 AERIAL SURVEY OF CONNECTICUT
There have been two projects at the Connecticut State Library to preserve and provide online access to the 1934 aerial photographs. The Connecticut State Library, State Archives has 8,731 black-and-white prints from the 1934 aerial photograph flight. In addition, there are 239 mosaic panels, which were created from the individual photographs in 1934-1935.
There was no back-up copy because the nitrate negatives were destroyed long ago, there was a continual risk of damage due to wear and tear, some prints had gone missing over the years and the acidic envelopes were a poor storage option.
The State Library received 10,500 envelopes in 1934 but many envelopes were empty because a large number of photographs were deemed unusable. This could be because there were clouds in the picture or due to human error (Hartford daily courant Mar. 31, 1935 p. D3). The photographs start with number 00035 and end with 10,484. In all 8,731 photographs were available for scanning. Because the flight lines overlap by 60% and because photographs were taken every 25 seconds there is sufficient coverage that every area of the state is adequately represented.
SCANNING THE 1934 MOSAIC PANELS
The first effort was a collaboration in 2003 with the Map and Geographic Information Center (MAGIC) at the Homer Babbidge Library of the University of Connecticut to have the 239 mosaic panels scanned. The mosaic panels had a tic mark in each corner that indicated the latitude and longitude of that point, which was a help in geo-referencing them. Ben Smith, a Master Degree student at the university did this work. It wasn’t as easy as we hoped. Along the shoreline and the borders, he had to look for road intersections or buildings to get the panels to line up properly.
The mosaic panels were scanned by DataVault. Scanned at 400 dots per inch (dpi), the 239 mosaic panels created files of about 100 megabytes each, and when merged, created a 27 gigabyte file. This file has been compressed using a 'wavelet' compression and now the 239 panels appear as one seamless image. Users can zoom in on a point and move around from one end of the state to the other. Tips are available on Using the Mosaics and Maps on UConn Web Sites and use Internet Explorer to view the 1934 Aerial Mosaic Online.
However, because the mosaic panels were not as sharply focused as the individual photographs, researchers continued to use the individual prints heavily. It was considered important to proceed with a project to preserve and improve access to them.
SCANNING THE 8,731 PRINTS FROM 1934 AERIAL SURVEY
A further motivation was the fact that properly made and properly stored photographic materials have a life expectancy of 500 years whereas the successful long-term storage of digital images is still the subject of much debate.
Therefore, the State Library conducted a project to create new negatives, a set of new copy prints for use, and scanned images of the 8,731 individual photographs. Funding for this project was provided by the Historic Documents Preservation Program of the Connecticut State Library, which also contributed to the scanning of the mosaic panels.
In 2005-2006, the prints were sent to the Chicago Albumen Works where the first step was to scan them at 1270 dpi. This high resolution level was chosen because aerial photographs contain many fine details and subtle tones or shades of grey. It was very important to make faithful copies of the original prints. The high-resolution scans, which have been compressed for public online access, have given us the accuracy we hoped for.
One of the great challenges in copying a photograph is accurately capturing all the tones or shades of grey. The new negatives were made from the digital images using a machine called a Light Valve Technology Film Recorder. This machine exposed the negative film based on the tone values captured by the scanner. The LVT can be calibrated to minimize the loss of the light tones without making the dark tones too dark, providing a more faithful copy than traditional photographic duplication could do. The new copy prints were made from the negatives in the traditional way.
A grey scale bar was used when scanning the photographs as a way to judge that we produced a reasonably accurate copy. With the right software, the scanned photograph with the grey scale bar can be compared with the scan of an official grey scale bar to judge how accurately the shades of grey are printed.
Researchers can use the grey scale bar, along with the National Archives and Records Administration Monitor Adjustment Target to adjust the contrast and brightness of their computer monitors so that the scans of the photographs look their best.
NORTH ORIENTATION OF THE 1934 PHOTOGRAPHS
We deliberately scanned about half the photographs with the photograph numbers upside down in the bottom left corner. In modern aerial photographs, the north portion of the image is always at the top of the photograph when the number is in the top right-hand corner. But that is not true of the 1934 aerial photographs.
In 1934, the airplanes flew first north, then south, in a grid pattern and the north/south orientation of the film changed as the plane changed directions. The numbers were printed in the same corner of the film regardless of where north was on the image. Thus for some 1934 aerial photographs, north is at the top when the photographs number is printed in the top right corner. But for other photographs north is at the top when the number is upside-down at the bottom left.
The quality control steps, performed by Steve Rice and John Lenehan, included viewing all 8,731 sets, which consisted of an original print, a negative, a copy print and a scanned image, to look for obvious errors such as scratches or blurring. Ten percent of the sets were re-examined at great length, first under magnification to check for sharpness of the details and fidelity to the original print. Then, the negative was measured with a densitometer and the histogram of the scanned image was measured to discover the levels of light and dark tones. This information will give us a reference point for subsequent inspections as the negatives get older and scanned images are transferred or migrated to other equipment.
As work was completed, the copy prints were made available to researchers, the negatives were moved to a temperature-and-humidity controlled vault and the original prints were put into acid-free envelopes and stored in another State Library facility.
CENTER POINTS OF THE 1934s
The latitude and longitude of the center of each photograph was identified by trying to find the same point on an online, geo-referenced U.S. Geological Survey topographic map. There were some difficulties with this process. For example, the Barkhamsted Reservoir did not exist in 1934. It is difficult to pin point the center of photographs of land that is now under water.