In the early ’80s, Dhiru Thadani was so disgusted by the proposed design of the Techworld buildings in Chinatown that he decided to map the public space around the area. Thadani intended to show how the complex, which was intended to lure technology companies to D.C. and now blocks off 8th Street NW, would mar its surroundings. Much to Thadani’s dismay, the map couldn’t stop the building. But Thadani had gotten his first taste of mapping Washington—and he liked it.

So for the next 22 years, Thadani, a founder of the New Urbanist movement in architecture, spent most Saturdays mapping the relationships between interior and exterior public spaces in D.C.’s monumental core—building by building, block by block. While working on the Techworld-area map, Thadani had realized that there were few good base maps of D.C. But more important, he’d realized that there were no maps that showed public space in the way that he saw it: as “outdoor rooms.”

“We’re talking about 1982, when it was all Xerox and photographic reproduction. No digital imaging at all,” says the 49-year-old 16th Street Heights resident, who estimates that he spent $1,500 on fine-point rapidograph pens over a period of about eight years.

Around the time he began the Techworld project, Thadani came across a 1748 map of Rome designed by Giovanni Battista Nolli. Nolli’s map rendered private buildings as black footprints and included the floor plans of public buildings in white. “There are many architects who don’t know what a Nolli map is, unfortunately,” says Peter Hetzel, who was Thadani’s business partner for 15 years. According to Hetzel, modernist architecture’s impulse to erase history caused many architects to overlook approaches to rendering public space such as Nolli’s.

“As I found out more and more about the Nolli plan, my endeavor didn’t seem so crazy,” says Thadani. It helped that other architect friends soon got excited about the project, too. Every Saturday, a dozen or so of them would walk around the city, verifying building footprints, coming up with unorthodox strategies for getting floor plans, and counting curbs. Later, they’d go back to Thadani’s studio for wine and food, and to talk about what they’d seen. Early on, Thadani decided to make 1991, the 200th anniversary of the L’Enfant plan, his project’s cutoff date; this goal allowed him to evade the temptation to constantly update the map, even as the city changed before his eyes.

Finally, in 1998, Thadani got his map digitized and placed on 100 CD-ROMs, which are currently being sold by the D.C. chapter of the American Institute of Architects; the map is also reproduced in the recently released compendium Washington in Maps. Though the published version shows footprints, trees, streets, and sidewalks, it leaves out the floor plans—the result, Thadani says, of post-9/11 security concerns.

He’s quick to bemoan the impact of metal detectors and barred-off entrances on the buildings that he loves. “You come into this fabulous lobby and it’s just not gracious. Civic buildings need to have that kind of graciousness. That’s what empowers them.” —Bidisha Banerjee