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. 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.