Ecology has always been a bit doughy compared to subject like physics, chemistry, and hell, even biology. But cut ecologists some slack. The places they study, like alpine prairies, peat bogs, or oases, are the diametric opposite of controlled lab settings. So how do you bring hard data to the study of life on our soft planet? A new map.

The Global Ecological Land Unit map is the most detailed look ever at Earth's ecosystems. Basically, it partitions the planet into squares 250 meters on a side—roughly the size of a couple of football fields. An ecosystem looks at lithology (that's rocks and dirt), climate, topography, and land cover—from pristine forest to pavement. Each square on the map combines those categories of data, and every pixel can be described in a single sentence—say, warm, wet hills on volcanic rocks with mostly evergreen forests. Underneath: reams of reference. A world's worth of data.

The US Geological Survey pulled that information from a wide swath of sources—soil surveys, digital elevation models, satellites, weather stations. But the agency didn't have the computing power to chew it into meaningful maps. So, they partnered with Esri, the titanic digital mapping company, which marshaled an army of geographers, analysts, and cartographers to knit everything together. Ecologists have always relied on maps made by experts based on their on-the-ground research. They were good, but subjective. Data is better. "It’s a huge confidence boost to the scientists that we are on the right track to understanding things in a comparable way," says Charlie Frye, Esri's chief cartographer. After sharing it with veteran ecologists, Frye says they responded by telling him that this map showed them what they already knew, but at scales they'd never seen before.

And what's good for research is good for conservation. The maps will help land use managers make better estimates of an ecosystem's economic value. This can make a good counterargument for conservationists facing off against parties who, for instance, think empty, windswept shoreline would be much better with a crowded boardwalk.

One of the biggest uses for the map will be for climate change research. It sets a baseline for global ecosystem locations, so researchers can watch how ecosystem distributions change under climate change. The data allow for modeling backwards and forwards in time, so the new map becomes a way to understand past and future ecosystems, says Roger Sayre, the agency's point man on the project. And map-oriented amateurs can play along with the ecologists—Esri also put together a web-hosted version for armchair ecologists. Sayre says these maps let the public get familiar with the way ecologists view the earth. "We’re putting a concept out there that ecosystems are these areas of unique landform, climate, geology, and vegetation," he says.