"Our goal is to be able to have layers of information, from terrain and buildings to troop movements. Our maps have to be relevant, timely and accurate," said Darryl Garrett, NIMA's chief technology officer. "I don't know of anyone else in the world who's as comprehensive as we are."

The ultimate goal, he said, is to fill the agency's supercomputers with 40 "petabytes" of data on mapping and analysis. That's 20 times the amount of all the data that's on the internet today.

Garrett won't say how far along NIMA is toward that goal, but the $200 million the agency is spending on the shuttle radar mapping mission should be a big help. The mapping data is nine times as detailed as what's available today, allowing the agency to better complete such tasks as charting 60,000 airfields throughout the world.

NIMA's customers range from the Pentagon and intelligence services to the Interior Department and the Federal Emergency Management Agency. The State Department has used NIMA's maps to delineate borders in Bosnia and the Golan Heights. Two years ago, NIMA helped the U.S. government broker a peace treaty between Peru and Ecuador by providing detailed maps of a border that had been in dispute for 40 years.

Closer to home, NIMA provided satellite maps of St. Louis, Missouri last year so the Secret Service could set up security for Pope John Paul II's motorcade. And at the request of the Air Force last year, the agency's spy satellites helped in the search off Martha's Vineyard for John F. Kennedy Jr.'s plane.

NIMA was founded in October 1996 with the merger of the old Defense Mapping Agency, the Central Imagery Office, the Defense Dissemination Program Office and the CIA's National Photographic Interpretation Center. Also included in NIMA are parts of the Defense Intelligence Agency, the National Reconnaissance Office (NRO) and the Defense Airborne Reconnaissance Office.

NIMA's 7,000 employees are spread through three states and the District of Columbia and representatives can be assigned to U.S. military bases stateside and overseas. The Bethesda headquarters is responsible for maps and analysis that focus on surface and water features, while an office in St. Louis, Missouri concentrates on aerial and satellite imagery features. NIMA also has branches in Reston, Virginia and at the Washington Navy Yard.

"The main reason you had this merger is that there was a growing convergence of the imagery business and the mapping business," said John Pike, space policy director at the Federation of American Scientists in Washington. "In the old days, you had film and paper maps. Now you have digital information systems and there's less and less difference between imagery and maps."

One of NIMA's main duties, Pike said, is to decide which targets are to be photographed by the nation's spy satellites on any given day. "They're the ones that say, 'Out of the 5,000 pictures we're going to take today, these are the ones we're going to take.' Your spy satellites are operated by the NRO but they are operated for, and at the direction of, NIMA."

Bringing the nation's super-sleuths together under one umbrella agency was no easy task, said Garrett, who arrived from the CIA the first month of NIMA's operation.

"It was like a shotgun marriage sometimes," he said. The intelligence-gathering and mapmaking cultures were not a ready fit. People who had been working for components of the CIA suddenly found themselves working for the Department of Defense.

One thing that did continue was the secrecy. Visitors are discouraged -- this includes social calls by spouses or family members of NIMA employees. Workers in the most sensitive jobs must take two lie detector tests as a condition of employment -- one to measure their risk to national security, the other to assess their personality.

From the start, there was plenty of work to go around. "My first day on the job, I had no computer, no trash can, no secretary and my phone rang off the hook for three solid days," Garrett said.

There were stumbles along the way. Two years ago, NIMA and other U.S. intelligence services were criticized for not detecting in advance that India was about to test a nuclear weapon. And last year's mistaken U.S. bombing of the Chinese embassy in Belgrade was blamed on NIMA, even though the agency's maps of that city were intended only to be used for civilian evacuations, not for purposes of targeting.

Today, NIMA assembles its maps from a variety of sources, including high-resolution commercial satellite photos from companies in Canada, Russia and France.

One of the agency's main projects is creating sophisticated software maps for laptops that can be used by military pilots and soldiers. The maps can zero in on a particular location in much the same way that web surfers use "address finder" websites to get maps of a particular neighborhood.

"We call it 'NIMA-in-a-box' and it's all built out of commercial equipment," said Garrett. "It's a portable mapping system that can get you down to street level. It's $12,000 to $15,000 worth of equipment you can buy with a credit card."

NIMA-in-a-box already has proven successful in the field. A U.S. F 16 pilot shot down in Bosnia a few years ago used the device to tell rescuers precisely where to find him. He was rescued after just 90 minutes on the ground.

Down the road, NIMA plans to refine its 3-D maps, making them similar in quality to high-definition television.

"You can use game technology like in Doom and Quake to do visualization," Garrett said. "If I'm a rescue team to go rescue hostages, I need to know what the area looks like from all angles. We have to figure out smart ways to make use of the commercial technology that's already out there."