With the base established, each sectional is built from, typically, 53 layers of information, each layer a separate transparent sheet, all laid atop the map base. Each contains only the uniform graphics and color that are assigned to it. One layer has nothing but uncontrolled--airport symbols, little magenta circles with at most a runway or two shown. Another has control-tower airports, colored blue, with the runways depicted in scale. Another layer is nothing but man-made obstructions. Another: VOR (Very High Frequency Omnirange) compass roses. Another: yellow "urban tint" denoting built-up areas. Water. Highways. Drainage areas. Mountainous elevations. Radio-frequency boxes. Restricted areas. And so forth, amounting to, in the case of the particularly complex Los Angeles sectional, nearly 70 layers.
Continental U.S. sectionals are revised and reprinted every six months--twice the frequency of British and German air charts, which are generally considered to be in a class nearly as good as those of the U.S.--so the individual chart layers are constantly under revision. (Most Alaskan sectionals are renewed annually.) An updated master goes off to the printer every 28 days, since chart revisions are staggered to spread out the workload.
Changes can be wrought by everything from a private pilot calling AC&C (800 626-3677) with the news that the road west of Middletown shown as two lanes sure looked like four when he flew over it, to a mayor writing to announce that his town had just erected a new water tower and it would be swell if the chart honored it. Says Carl Nixon, chief of the Visual Chart Branch, "One of our best sources of new information is simply people flying around looking out the window. We get one or two tips a day, most of them phoned in."
Wander through AC&C's offices and you'll also see Rand McNally road atlases on many a desk. "We use the best available source of information," Nixon says, "whether it's a road atlas or a newspaper clipping." But this is only the first stage in a chart revision. AC&C never takes anything for granted, whether it's a phone call from a pilot, a letter from an electric company announcing completion of a power line, or even an official document from the Federal Aviation Administration. Everything is double-checked, sometimes by cartographers demanding photo verification.
The ultimate proof is "flight editing." NOAA has a small fleet of twin-engine airplanes--a Shrike Commander, Turbo Commander, and Citation business jet--that fly back and forth, over the ground covered by sectionals, like lawnmowers cutting row after row of grass. The in-house joke is that the pilots are simply scouting for nice places to retire to, but in fact they're checking virtually every item on the busier sectionals. They come back from their mind-numbing missions with notes that eventually are scribed onto the margins of the sectional under revision: "add new tower," "dragstrip still good landmark," "airport north of road," and, as the last of the drive-ins crumble, the frequent "delete outdoor theater."
"I get upset when pilots tell me that they can use an outdated chart for several years," Ronald Bolton says. "We can have 800 changes on a single sectional in one six-month cycle." Still, many pilots resist spending $7.25 per chart twice a year. Which in my case, as a pilot who ranges the occasional thousand miles from home base, means a not--unreasonable collection of 10 sectionals for compete coverage: $145 a year. Dare I upset Bolton? I break down and buy a new set of sectionals only when my prime chart--the New York sectional--wears out from constant use. (But if an FAA inspector ramp-checks my airplane and finds out-of-date charts, I could get the aeronautical equivalent of a ticket. And were I to have an accident, particularly as a result of getting lost, my negligence could be used against me in an FAA enforcement action.)
The Office of Aeronautical Charting and Cartography is on the cusp of change--some of it good, some of it the subject of much contention. For one thing, the Department of Commerce is trying to kick them out. "Commerce says we no longer fit in NOAA, which is primarily an environmental organization," says director Terry Laydon. "The aeronautical charting business started with charts intended to promote interstate aeronautical commerce, which is why I keep saying we belong in the Department of Commerce." Commerce, however, wants the AC&C shifted to the Department of Transportation, where it probably would be placed under the FAA. "We're concerned about that," says Laydon, "because it isn't clear that the FAA will support the non--aeronautical part of our activities, such as printing and distributing nautical and military charts." Laydon sees obvious efficiencies in the consolidation of such production.
If they do go to the DOT, the Aeronautical Charting and Cartography Division will be renamed Transnav--short for Transportation Navigation Services. But this is the least of Laydon's concerns. "We don't have a lot of name recognition anyway," he says. "Our charts are known as 'NOS charts' [National Ocean Survey] or 'Nozz charts.' Nobody calls them AC&C charts."
The positive changes, however, are the AC&C's increasing reliance upon computerization and automation, the goal being the eventual disappearance of the cartographer's traditional tools and techniques. "It's a dying art," says printing specialist Nick Alsop as he demonstrates how corrections compiled from flight editing and other sources are hand--engraved onto huge plastic sheets. "We'll probably see all of our tools in the Smithsonian someday."
At one end of the spectrum are Alsop and senior cartographer Ray Harris, who uses nothing more than a Koh-i-Noor lead pencil, an eraser, and an X--Acto knife to endlessly, laboriously draw the properly shadowed lumpiness of thousands upon thousands of square miles of mountainous terrain all over the United States. Harris uses as his guide an underlay of U.S. Geological Survey topographic contour lines and an understanding of how the land will thus fall, fold, and furrow.