The National Geographic Society, appalled at America's ignorance of geography, celebrated its centennial yesterday with a $20 million foundation to fight the problem.

At the same time it opened a dazzling show at Explorers Hall featuring records of early Geographic exploits, the newest thing in 3-D video and one of the biggest holograms in the world.

"Thirty percent of the students at a Florida university couldn't locate the Pacific Ocean," society President Gilbert M. Grosvenor told a press conference. "Fifty percent of the college students on the West Coast couldn't find Japan. And 95 percent of the college freshmen in the Midwest don't know where Vietnam is."

In Baltimore, he said, 45 percent of the high school seniors, asked to shade in the United States on a world map, couldn't locate their own country. And geography, he added, downgraded as it has been since World War II in favor of driver education and other novelties, "is essential in today's world ... If you don't know where you are, you're nowhere."

Without a basic knowledge of our planet's surface, how can one deal with such global issues as drought, deforestation, air pollution? he asked. He speculated that unrealistic bank loans to developing countries could be traced to geographic illiteracy, that even our foreign trade deficit is related to lack of elementary knowledge of the rest of the world, its physical resources and industrial potential.

The National Geographic Society Education Foundation will begin by training teachers and awarding grants for geographic study. Eventually, through further pledges and matching grants, the society hopes to raise $100 million under its "mandate to popularize geography in the school curriculum."

The foundation's goal, Grosvenor said, is to achieve geographic parity with the rest of the world within 10 years. Schools in Europe, he pointed out, require five years of geography. In Japan, pupils attend school 240 days of the year, compared with 183 for Americans.

We are decades behind Western Europe, Australia, Japan, Canada, he said, and this is disastrous, because "geography helps drive history."

A program in geography education was launched by the society three years ago. Copies of a new historic atlas of the country -- the latest in a long tradition of superb NGS maps -- are being donated to every junior and senior high school in the United States at a cost of a half-million dollars.

But the new foundation, to be headed by Lloyd H. Elliott, president of George Washington University, is, as Grosvenor put it, "the centerpiece of our centennial."

Not to put down the lavish new exhibit, which remains open through 1988.

It starts, like any corporate production, with itself: reminders of that fateful meeting of certain visionary men at the Cosmos Club Jan. 13, 1888, to establish the society.

The magazine, born nine months later, was distinctly an amateur operation, with an unpaid staff. Then-editor Gilbert H. Grosvenor published some of his travel photos, for instance. Luckily for us, they are fascinating: haunting glimpses of prerevolutionary Russia in 1913.

A slide show gives a quick review of some stories covered by the Geographic in the early days, notably the digging of the Panama Canal in 1911. There are posters for the Africa films of Martin and Osa Johnson, part of the movie-going childhood of anyone over 50. One teaser: "From a woman's standpoint: the sensations of living among the gnome-like pygmies."

There are fuzzy but hair-raising movies of the first overland trip across Asia, 7,370 miles from the Mediterranean to Peking, in a half-track vehicle that sometimes had to be dismantled to get it past certain obstacles.

There is lean young Hiram Bingham at the site of his fabulous discovery, Machu Picchu, the Inca city above the clouds, in 1911. The first interior photo of Carlsbad Caverns, 1924, with its giant chamber half a mile across. The first photographic proof that the world is curved, 1935, taken from an NGS balloon that rose 72,395 feet into the stratosphere.

And Lindbergh and Earhart, and the first dive by Cousteau using an aqualung, an invention that opened a new dimension in exploration, including the discovery of lost ships from the HMS Bounty to the Titanic.

And the first pictures from the top of Mount Everest. The Geographic goes everywhere.

Incidentally, the Corcoran Gallery will open its own exhibit of 100 years of Geographic photographs -- seen as art -- in June.

But the show is just getting started. Here is a mock-up of a bathysphere, through whose portholes you can watch 3-D videos of feeding sharks, deep-sea eels and other creatures. The video, developed by staffer Emory Kristof and Lenny Lipton's StereoGraphics Inc., is an electronic first, flashing 120 images per second, alternating between the viewer's eyes, so that the stereoscopic picture appears remarkably real.

"This will have all sorts of applications in industry and medicine," said Kristof, who earlier had pioneered undersea robot cameras with the aid of Lipton. He said the Geographic has been spending a quarter-million dollars a year on this R&D.

Just around the corner is an enormous hologram, the design for the Parc des Folies a` la Villette, near Paris. This elegant landscape in green and red jumps clean off the wall to surround and literally include the passerby in its orderly little world.

And finally the visitor reaches a 100-seat auditorium where a 12-minute film, "Honoring the Earth ... Seeking the Stars," runs all day. Set on a wide screen, this beautiful show uses the video projection technology of something called Metavision to achieve an effect on videotape reminiscent of the revolutionary 1970 film "Woodstock." Three pictures appear on the wide screen; they melt together to form two, then one marvelous broad shot of, say, Earth and moon, or waterfalls, or the African savannas. Pictures play across the screen like music, swelling and fading. It is as exciting as anything shown on the Air and Space Museum's giant Imax.

The National Geographic Society has 10 1/2 million members, which means probably, Grosvenor says, 40 million readers. If you had been getting the magazine from its first issue, by now you would have a stack 52 feet high.

And you would certainly know where the Pacific Ocean is.