Yesterday the December issue of American Surveyor magazine appeared in my mailbox. American Surveyor is one of the few trade publications I read from cover-to-cover every month, and it’s one of the very few I’d gladly pay a subscription fee for. But since the publisher, Cheves Media, provides it free of charge all the better.
This month’s issue hits it out of the ballpark. The cover is one heck of a teaser – a beautiful shot of the John Bird transit telescope used by surveyors Charles Mason and Jeremiah Dixon to establish the boundary between Pennsylvania and Maryland just before the Revolutionary War. This is the famous ‘Mason – Dixon line’ that today is viewed (incorrectly) as the cultural and political dividing line between the American North and South. Mason & Dixon’s achievement is an important topic in the history of topography in the Americas and we’ll have more on it in a later post.
Today however we’ll focus on the other key article in the magazine – a short overview of the achievements of Ted (Talbert) Abrams, an early pioneer in the science of photomapping and and photogrammetry. Abrams was one of the quiet heroes of topographic history, someone most have never heard about but who’s accomplishments revolutionized science, established an industry and helped found the geospatial profession many of us practice in today.
Just what were Ted Abrams’ achievements? He effectively invented the business of photomapping. It was his experience as a US Marine Corps reconnaissance pilot during WWI that convinced him that aerial photography could be used to make highly accurate maps. At the time traditional mapping technology required the use of ground survey and field verification crews to literally walk and survey the areas to be mapped, usually using laborious plane table survey methods. The process was slow and expensive. One of the earliest uses of aircraft during WWI was to take vertical photos of battlefields for the creation of map substitutes. These were simple photo mosaics annotated with things like road and town names, but they filled a critical need.
Coming out of the war Abrams was convinced that photomapping could not just be a viable business, but could revolutionize the science of large scale mapping over broad areas. Ted Abrams was part pilot, part scientist and part entrepreneur, and all genius. Where no industry existed, he developed the techniques and the instruments necessary to capture and process tightly controlled areal mapping photography and compile accurate maps from that data. He then developed the business model that made it all profitable. He also helped develop a lot of the science behind the processes involved in photomapping. You can’t claim your maps and photo mosaics are accurate unless you can prove the mathematics and geometry that went in to making them, and Abrams was an early pioneer in developing the mathematical principles behind processes like aerotriangulation.
Ted Abrams was also a life-long patriot and a proud Leatherneck. During WWII he set up schools that trained thousands of Marine Corps photo mapping and photo analysis specialists, and his techniques and textbooks were in wide use across all the military services. One of his simplest yet greatest accomplishments was the invention of the folding pocket stereoscope. This stereoscope was manufactured by the hundreds of thousands by the Abrams Instrument Corporation and other manufacturers and became the indispensable tool of photo interpreters, surveyors, cartographers and intelligence analysts around the world.
Invented by Ted Abrams in 1942, the simple folding pocket stereoscope has been the indispensable tool of topographers for over 70 years. They are still in wide use today
After the war Abrams’ business flourished as America went on a building boom. He built Abrams Aerial Survey into the leading aerial survey firm in the United States and the Abrams Instrument Corporation became a leading supplier of aerial photography, photogrammetry and aerial photo analysis instruments.
Ted Abrams was a founding member of the American Society of Photogrammetry (now the American Society of Photogrammetry and Remote Sensing (ASPRS)) and much of his pioneering work made its way into the first editions of the industry’s standard reference, the Manual of Photogrammetry.
In recognition of Abrams’ contributions the ASPRS presents the Talbert Abrams Award every year to ‘encourage the authorship and recording of current, historical, engineering, and scientific developments in photogrammetry.’
One last example of Ted Abrams’ genius. He came out of WWI with a clear understanding of the limitations of current aircraft designs when used as platforms for aerial cameras. Abrams knew he needed a more stable aerial survey platform designed around the needs of the camera system and crew. In the 1930’s Abrams sat down and designed what became the world’s first dedicated aerial imagery platform – the Abrams P-1 Explorer.
First flown in 1938, it was specifically designed for the mission of acquiring aerial mapping photography. The P-1 incorporated a number of unique design elements, including a pusher-type engine arrangement designed to keep leaking oil and fluids from smearing the camera lenses (a serious problem with conventionally laid out aircraft using rotary engines), and it was one of the earliest aircraft to utilize Plexiglas for windows. In fact the nose layout made its way into WWII military aircraft designs, particularly the nose arrangement of the early B-24 Liberators.
Unfortunately the P-1 design was a victim of war. By the time the aircraft became operational proved itself as an outstanding aerial camera platform WWII had broken out. The US Army Air Corps looked at the design and deemed it too slow and too vulnerable to enemy fire. Ted Abrams realized he needed to work on ways to mount mapping camera systems in fast moving fighters and modified bomber aircraft and threw himself into the task without looking back. Only one model of the P-1 was ever built and it remained in operation in the US until 1948.
A fascinating aircraft designed by a true genius and pioneer in our industry. We truly do stand on the shoulders of giants.
Brian
Northing & Easting 