Eric Sanderson came up with the Mannahatta Project one evening in 1999 after buying a beautiful book of historical maps of the city. A recent deserter from Northern California, he was curious about developments in his host city. “The landscape of Manhattan has changed so much that you wonder what was before,” he said. There are some places in this city where you don’t see a single other living thing, except maybe a person or a dog. Not a tree, not a plant. How did a place get like this? »
One map in particular caught his attention: a splendid color print from 1782 or 1783 showing hills, streams and marshes, as well as roads, orchards and farms, all over the island; a unique feat of its kind for the time. Three meters long and one meter wide, this map was drawn by British military cartographers during their eight-year occupation during the American Revolution. This now-famous map, dubbed the “British Headquarters Map,” shows the island’s topography in an unusual light, as British officers needed special intelligence to be able to defend Manhattan.
Eric Sanderson wondered what would happen if we superimposed the Hippodamian plan of the current city onto this 18th century renderingAnd century. Would they stand in line even a little bit? To find out, Eric Sanderson recruited family and friends, starting with his wife Han-Yu Hung and their young son Everett, to accompany him on weekends to the places still visible marked on the old map. Trinity Church in midtown Manhattan, founded in the late 17th centuryAnd century, is one example among many. A typical headstone in the aster reads: “Here lies the body of John Abrell whose days ended January 10, 1762 at the age of 40”. Since the cemetery is locatable on both the British HQ map and the current grid, Eric Sanderson was able to, as it were, push a thumbtack through both maps by taking a GPS survey of the site and projecting it onto a digitized version of the old map. After repeating the process some 200 times, pin by pin, he and his team were able to match the “British Headquarters map” and the current Hippodamian plan with an accuracy of half a block, or about 39 meters. In Eric Sanderson’s view, a whole new dimension had been added to the modern urban landscape. He now he could stand anywhere in Manhattan and pretty much imagine what was in 1782.
Take the false floor of Fifth Avenue as you pass the New York Public Library (NYPL). “There’s a good reason that standing on the sidewalk here you can see the tops of people’s heads a few blocks away,” she explained. We are near the top of Murray Hill, where the Murray family had a farm and orchard in 1782. During the New York campaign, the British landed at Kips Bay on the East River and marched up here, squeezing half the army of Washington who was trapped in midtown Manhattan. A legend says that Mrs. Murray reportedly offered tea to British officers. They halted here at the farm, and while they were drinking tea, Washington’s troops slipped through their lines across the Bloomingdale Road, now Broadway, and fled. »
As fascinating as the famous British officers’ map was, Eric Sanderson had no intention of stopping his time machine in 1782. It was 1609 or nothing. With his colleagues, he then removed from the map everything that had been added by settlers and soldiers (roads, farms, fortifications, etc.) until his digitized version counted only the building cubes of the physical landscape elements: coast, hills, cliffs, land use, streams and ponds. As a landscape ecologist, Eric Sanderson used to mentally dissect wilderness areas to figure out how they worked; for example, separating a Gabonese tropical forest into geological, hydrological, ecological and cultural strata. But in this case, he and his colleagues set out to build a landscape from the ground up, starting with the earth and filling it with the plants and animals that presumably inhabited it.
