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When Lasers Took to the Air to Measure the Earth

Allan Carswell’s lidar systems helped map the waters of the Arctic and the atmosphere of Mars

2 min read
Allan Carswell
In this 1986 photo, Optech cofounder Allan Carswell considers a model of his company’s airborne laser system for mapping coastal waters in the Arctic.
Photo: Keith Beaty/Toronto Star/Getty Images

In 1974, lasers had been around for only 14 years. While there were a few applications in medicine and telecommunications, lasers were not the ubiquitous product that they are today. That year, Allan Carswell, a professor of physics at York University, in Toronto, decided that it was about time for someone to do something useful with a laser, so he and his wife, Helen, founded a company called Optech to commercialize the technology.

In the late 1970s, Optech started selling laser range finders, which use a single beam to determine the distance between the laser emitter and whatever object you pointed it at. Unlike most other range finders then on the market, Optech’s detectors were sensitive enough to work with “noncooperative” targets—that is, you didn’t have to point the laser at a reflector for it to work. By mounting an Optech laser range finder on an airplane and pointing it at the ground, you could then fly back and forth to build a topographical profile, which, when stitched together with other such profiles, formed a low-resolution three-dimensional map.

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How the Graphical User Interface Was Invented

Three decades of UI research came together in the mice, windows, and icons used today

18 min read
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Stylized drawing of a desktop computer with mouse and keyboard, on the screen are windows, Icons, and menus
Getty Images/IEEE Spectrum
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Mice, windows, icons, and menus: these are the ingredients of computer interfaces designed to be easy to grasp, simplicity itself to use, and straightforward to describe. The mouse is a pointer. Windows divide up the screen. Icons symbolize application programs and data. Menus list choices of action.

But the development of today’s graphical user interface was anything but simple. It took some 30 years of effort by engineers and computer scientists in universities, government laboratories, and corporate research groups, piggybacking on each other’s work, trying new ideas, repeating each other’s mistakes.

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