The booming economies of Gulf oil states. The rise in the global demand for meat. The continued migration of Americans to sprawling metropoles of the South and West. These major social and political trends of the past two decades aren’t just stats and figures--they’re stories inscribed into fast-changing landscapes, just as visible on satellite imagery as they are on the news.
Using satellite data from Landsat--the United States Geological Survey’s satellite imagery program that’s photographed Earth since the 1970s--Google constructed timelapses of some of the most rapid changes to the built environment that have occurred throughout the past couple decades.
The resulting archive, available on Google’s platform Earth Engine, provides a shocking perspective of the pace of economic growth across the world, with its myriad consequences for natural and man-made environments, and the ability of capital investment to create whole cities out of nothing--or in the case of Dubai--even build islands where there was once nothing before.
"We believe this is the most comprehensive picture of our changing planet ever made available to the public," Google engineering manager Rebecca Moore writes on the company blog. Timelapses include the irrigation of the Saudi desert, the disappearance of Iran’s Lake Urmia and the Aral Sea, the retreat of Alaska’s Columbia Glacier, and the deforestation of the Brazilian Amazon.
Moore gets into detail about how these captivating images were created:
We started working with the USGS in 2009 to make this historic archive of earth imagery available online. Using Google Earth Engine technology, we sifted through 2,068,467 images—a total of 909 terabytes of data—to find the highest-quality pixels (e.g., those without clouds), for every year since 1984 and for every spot on Earth. We then compiled these into enormous planetary images, 1.78 terapixels each, one for each year.
As the final step, we worked with the CREATE Lab at Carnegie Mellon University, recipients of a Google Focused Research Award, to convert these annual Earth images into a seamless, browsable HTML5 animation.
Beyond creating something pretty to look at, Moore describes the purpose of the project as follows: "This time-lapse map is not only fascinating to explore, but we also hope it can inform the global community’s thinking about how we live on our planet and the policies that will guide us in the future."