Engines of Our Ingenuity

No. 284:
AERIAL MAPS

by John H. Lienhard

Click here for audio of Episode 284.

Today, we change our view of the world. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

As a young model-airplane builder, I sent my proxies into the sky, while I -- bound to the earth -- could only watch from below. I thought a lot how I could make them tell me what they'd seen up there. Once I put a tiny camera, with a pneumatic timer, in the belly of a huge glider I'd made. But all I got for my trouble was a gray blur.

My fascination mirrored 19th-century fascination. Photography had matured quickly after the Daguerreotype process proved workable. Those first pictures took fifteen minutes to expose. But cameras were now being turned on everything in sight, and film speeds were relentlessly being improved.

Balloons also captured the 19th-century mind. So it's no surprise that in 1858 a Paris photographer took his clumsy gear 240 feet into the air to photograph the village of Petit Bicetre. A Paris cartoonist jibed at him for carrying photography to the "highest" art, but no matter. The seed was sown.

Mapmakers saw the potential of combining cameras with flight from the beginning. In 1839 a scientist told the French Academy that the new art of photography would serve mapmaking. A mapmaker named Laussedat had already tried to photograph the earth from a kite. When that failed, he went on to develop earth-based techniques for combining photography with surveying.

Balloons also failed to provide the stable and navigable platform that was needed for aerial mapping. But as the airplane matured, it was able to serve that purpose. Aerial photo-reconnaissance became a prime element in the business of WW-I.

As a result, you could buy a commercial aerial-mapping camera by 1920. Of course a camera gives you only a photograph -- not a finished map. Twenty hours of data reduction are needed to process an hour's photography. But anyone who's walked the woods as a surveyor knows the hard alternative.

Now computers and image enhancement are bringing whole new orders of accuracy to the business. Suddenly, we have topographical maps of the far side of the moon and the canals of Mars.

Being able to stand and see what we could only imagine before changes what we see. When I was five my father showed me a panorama shot from a balloon 66,000 feet above the Black Hills. He pointed to the gentle curve of the far horizon and said, "See, the world really is round." Suddenly I knew that outrageous claim was true after all. Twenty years ago we first saw the island Earth as it looked from the moon -- all fragile, blue and white, and far more beautiful than we'd dreamed. And it hasn't been the same place since.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Wilford, J.N., The Mapmakers. New York: Vintage Books, 1982, Chapter 15.


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.


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