In the face of so much shocking and widely available imagery, why does the boot look the same as it did in the 1930s? That was why Jeff and I started devising an expose—this expose—about the boot. In our imagining, the idea spread beyond the confines of journalism, sparking a movement united around the cause of revising the boot in the spirit of advocacy and accuracy. Supporters would mobilize armed with t-shirts, stickers, and posters, all printed with the image of an alternative boot. More wine brought talk of a website and a conference launched under some incendiary title. (The Map is a Lie! Change the Map Now!) Politicians across the ideological spectrum would find common ground on the issue, because one thing environmentalists and global warming deniers can agree on is the basic fact that Louisiana is shrinking. The rest of the country would take notice, forging national agreement on the Master Plan and its funding as the most effective means for averting economic catastrophe. And then Jeff and I wouldn’t have to worry about tripping over more corpses, or being forced to move someplace with inferior cuisine.

South Louisiana has always vexed cartographers. Lawrence N. Powell’s book The Accidental City: Improvising New Orleans is front-loaded with tales of early explorers being led astray by maps that were imprecise at best. In the 16th century, Spanish explorers relied on charts that showed the Mississippi “emptying into the Bay of Espíritu Santo, in present-day Texas.” When Pierre Le Moyne d’Iberville, the Canadian who helped colonize Louisiana for France, arrived in the late 1600s, in search of the river’s mouth, he “carried with him a fraudulent map prepared by a disgraced Récollet missionary. It depicted a mythical east fork of the Mississippi.”

“Louisiana has perhaps the most complex coastline of any state in the union. It’s not just a coastline but a coastal zone that has many inland lakes that are part of coastal change,” said Snead. “Any map you make of the Louisiana coast is obsolete the day you make it. It’s an exercise in futility.”

Snead was the first person I called in my pursuit of the truth about the boot. He neither agreed nor disagreed with my theory that it’s a disingenuous artifact. Cartography, as Snead explains it, requires navigating tensions between precision and compromise. The 2000 map, he explained, is “‘official’ because there is an act of the legislature that says the Department of Transportation will produce an official map of Louisiana. And you should be aware that the legislature is full of politicians.” Elected officials, according to Snead, are not so concerned with the map depicting an accurate coast as they are with the visibility of the public works projects, like highways and canals, that signify their accomplishments. Complicating matters is the sheer expense of collecting the fresh data necessary to render a land-water interface perpetually on the move. As a consequence, the Louisiana map holds “a very generalized coastline,” according to Snead, that “is hard to draw even under ideal conditions. You have to have a very large scale to render it.”

Harold Fisk’s maps of the lower Mississippi River valley (U.S. Army Corps of Engineers)

Viewed from a distance, the shape of Louisiana on Snead’s 2000 map isn’t noticeably different from the boot. But its larger scale allows for the wetlands along the coast, particularly in the southeastern part of the state, to convey some of the porousness that is so obvious when you actually see them in real life. On the boot, those same feeble swamps and marsh appear as invulnerable as Iowa farmland.

The 2000 map was the first Louisiana map ever created entirely digitally using Geographic Information System (GIS) software, which enables the storage, management, and manipulation of massive quantities of geographic and scientific data. GIS technology is behind the spread of the web-based mapping tools that have disrupted the paper cartography trade in a manner similar to how the internet disrupted every other business tied to the printing press.

James Mitchell, the GIS manager at the Louisiana Department of Transportation and Development, is a former professor in environmental studies at Louisiana State University with the confident air of a person in possession of truths you may not be able to handle. His embrace of GIS technology is tempered by a frustration over what he sees as the public’s tendency to see digital maps as windows to the material world. “No one questions these things,” Mitchell told me when I met him at D.O.T.D.’s state headquarters in Baton Rouge. “A map is a model. It’s an abstraction of reality. So by making a model of reality, we can’t depict anything exactly.”

He pulled up a PowerPoint to help illustrate what he calls “Mitchell’s first rule of GIS: Everything you know is wrong,” which basically boils down to the idea that GIS technology is only as good as the data you feed into it. His experience updating maps with digital tools has exposed how inconsistent existing maps already were. “The topographic layer might have been done in 1956, and the land cover layer was done in 1962, and the transportation came from 1945,” Mitchell said of his findings. “And those are some of the good ones.”

Mitchell said the aerial photography and satellite laser data that lend GIS maps their lifelike immediacy pose problems of their own, particularly in Southeast Louisiana. He pulled up an aerial image of Pass Manchac, the channel between lakes Pontchartrain and Maurepas. On both the image and the Louisiana state map, the area appears to be forest. Anyone who has visited the flood-prone town of Manchac, about a 45-minute drive northwest of New Orleans, knows it is surrounded by wetlands. “People see the vegetation and the trees and think it’s land,” Mitchell said.

Setting aside the disorienting business of mapping swamps, Kurt Johnson, a former U.S.G.S. hydrologist and Mitchell’s colleague, pointed out that Southeast Louisiana’s dizzying interface of coastal tides, river currents, and sinking land can make what appear to be distributaries flow like tributaries, and vice versa. The hydrology is so atypical that he and Mitchell believe USGS should establish new protocols for collecting the dataset it uses to portray surface water on maps.

In March, I boarded a seaplane that took off from a canal in Belle Chasse, a suburb across the river from New Orleans, for a bird’s-eye tour of Louisiana’s imperiled coastline. The vulnerability is unmistakable from the air.

Our flight path took us south and then west, away from Lake Pontchartrain and across the Mississippi River, which winds east through the city before angling sharply downward en route to the mouth. New Orleans is nestled between the river and the lake. On a map it appears as if the city sits comfortably inland from the ocean. In reality, Lake Borgne, which land loss has allowed the gulf to annex, is knocking at New Orleans’s door from the east. Much of the “land” separating the city from the ocean to the south isn’t really land. It’s deltaic swamp and marsh that satellite images — a crucial source of mapping data — cause to appear indistinguishable from inland soil when reduced to the low-resolution shorthand that is Louisiana’s boot. But wetlands are not terra firma. Communities like Delacroix, an island in the wetland wilds below New Orleans, looks from the air to reside on the tips of reeds. It persists mainly due to the obstinance of its inhabitants.

By the time we reached Grand Isle and nearby Port Fourchon, south of Galliano, both just west of the bird’s-foot delta, our flight had provided us a sizable visual sample of arguably the world’s least stable coastline. At one point, as our pilot was preparing to announce our arrival at tiny Caillou Island, only to discover it under water, he said, “There’s supposed to be land here. There was a couple weeks ago.”

Comparable examples of incidental tragicomedy occur whenever I commune with Louisiana’s coastal estuary. I’ve never set foot on a boat in Louisiana without hearing my captain offer a running commentary on the landmarks — cypress trees, barrier islands, fishing camps — that have recently disappeared, casualties of the encroaching gulf.

“How do you represent a place where there is no edge?” asked Jeff Carney, director of L.S.U.’s Coastal Sustainability Studio. A wall of his studio on the university’s Baton Rouge campus contained various map-like representations of what he calls South Louisiana’s indeterminate landscape. As Carney put it, “We don’t have a shoreline. We’re not Florida. It’s not like you’re on solid ground and then you step into water.” That “unclear edge,” Carney said, “creates problems with land ownership, insurance, all of these things. We don’t deal with ambiguity very well.”

Carney, in partnership with the state, is trying to capture this fluidity with data visualization tools that communicate the progress of the Master Plan’s sundry land building projects. Because many of these projects will employ Mississippi River diversions to create land over time with sediment-filled water — in essence flooding land and wetlands you’re endeavoring to protect — detractors fear the Plan could cause more harm than good. Members of Louisiana’s seafood industry are particularly vocal opponents, because the fresh water from diversions kills oyster beds and chases other prey offshore.

Carney, a professor with degrees in architecture and regional and city planning, nimbly mingles left- and right-brain concepts. He said one of the goals for his maps will be to help “develop a language that doesn’t undermine confidence but actually allows people to better understand the environment we live in.” Thinking out loud, he began drawing a series of curving lines on a piece of scratch paper. Carney’s sketches brought to mind the famous maps Harold Fisk created in the 1940s that visualized the various paths taken by the Mississippi River before it was artificially fixed in place (that’s them running alongside this section). The maps look as much like posters in an art museum’s gift shop as pages from an atlas. They also effectively communicate the scale of a never-ending engineering conundrum whose complexities continue to fill shelves of doorstop-size books.

Carney was imagining how wetlands could be depicted “as neither land nor water” on future maps, encouraging people to recognize them for what they are. “Louisiana has an inferiority complex about its wetlands. We don’t understand them, so we dump everything into them. We tear them apart,” Carney explained. “But what if we had a way of drawing future maps that said, basically, all that fluffy green stuff is actually protecting everybody and building our economy?”

The political drama in Louisiana over the past year has revolved around the disappearing coast, the oil and gas industry’s role in contributing to it, and a lawsuit that seeks billions of dollars from the energy companies for the damage they’ve caused the environment.

Louisiana is both the country’s second-biggest crude oil producer and refiner and the largest entry point for crude oil coming into the U.S. (It is also near the top in the nation in total and per capita energy consumption, a reminder that producing energy requires a lot of fuel.) Oil and gas removal exacerbates subsidence of land, and the canals the companies have dug through the marsh disrupt the delicate balance of salt and freshwater in wetlands, killing plant and wildlife and causing erosion on the interior swamp and marsh already threatened on the outside by global sea level rise.

“It’s crystal clear, according to every single scientific study, including studies done by the [oil and gas] industry itself, that industry activities are responsible for a substantial part of the land loss,” said John M. Barry, the best-selling author of Rising Tide: The Great Mississippi Flood of 1927 and How It Changed America and former vice president of the Southeast Louisiana Flood Protection Authority-East (SLFPA-E), the government body charged with overseeing the flood protection system covering most of metro New Orleans.