The Art of the Chart
Somewhere in those symbols, lines, and colors is all the information you need to fly from here to there.
- By Stephan Wilkinson
- Air & Space magazine, November 1999
I have in my airplane a microchip miracle: a small, expensive, ever-changing, dead-on accurate, utterly magical moving--map cockpit display. Driven by an assemblage of silicon powerful enough to run Rhode Island--well, at least to operate all its traffic lights--the unit sniffs data sent to it by Global Positioning System satellites. It instantly and continuously does the arithmetic necessary to say to me at all times, "Here you are, dummy, right where the little airplane symbol on the map is."
See the little mock-Cessna chugging along over highways, rivers, and radio beacons? See the screen display zoom out to show it crossing all of North America at an imperceptible rate? And then zoom in to make it herky-jerk at 200 mph across my hometown streets? That's what aeronautical charts have come to: green and black pixels on a screen the size of a playing card, doing their best to approximate the basic outlines of the world below.
Frankly, I prefer the old-fashioned way. It uses paper, ink, art, artisanship, and nearly a million tints to produce what pilots call sectional charts.
Sectionals don't need batteries. They won't break if you drop them. They never flash a red light and announce "WARNING: SIGNAL LOST!" They can be consulted on the kitchen table or in the bathroom. And they cost only $7.25 apiece.
Since 1927, pilots have navigated U.S. skies by using paper charts produced by what is today called the Office of Aeronautical Charting and Cartography (AC&C), part of the National Oceanic and Atmospheric Administration and thus a ward of the Department of Commerce. Sectionals began as strip maps showing the landmarks and terrain between basic destinations, the very first of them Moline, Illinois, and Kansas City, Missouri.
In those days, landmarks were roads, rivers, railroads, towns, fairgrounds, and the occasional lighted beacon, and the pace was slow enough that the charts were accompanied by text descriptions of the route, sometimes on the other side of the chart. "People would fly and take notes for the pilots who'd be coming along behind them," says Christo Cambetes, a NOAA staff cartographer.
Today, raging civilization has built cell phone towers, drag strips, domed stadia, airports, dams, skyscrapers, race tracks, power lines, many-spired Mormon temples, parachuting sites, Disneylands, radio astronomy antennas, tank farms, ski lifts, power plants, and a hundred other "cultural features." Today, they're all included on sectionals. Says Terry Laydon, director of the AC&C, "The FAA comes up with the [general] concepts and features to be depicted on the charts, but we develop the standards and then work out the issues--what should be depicted and how it should be presented to the pilot."
"The standards" have been collected in an inch-thick volume that spells out everything from how to depict a kanat (an underground aqueduct with surface air vents) to the symbols for "populated places in ruins," the difference between wadis and sebkhas in a desert, and when a rock that is "bare or awash" is big enough to be shown as a tiny island. Read it and you'll understand why AC&C map--makers all have degrees in cartography: There are 147 symbols for topographical and cultural information alone, with nearly 100 more for purely aeronautical features, and each is specified right down to type face and size, color, and line thickness. And what the cartographers must constantly keep in mind is that all this information has to be made crystal clear to a pilot reading a chart with one hand and flying an airplane with the other.