By Chris Herwig, Geo Data Engineer, Google Earth Engine
Earlier this week, the Landsat Program celebrated its 45th year of continuous Earth observation. Landsat, a joint program of the U.S. Geological Survey (USGS) and NASA, offers an unparalleled record of our changing planet, with satellites that have been observing the Earth since 1972 to the present day.
At Google, we use Landsat data on a daily basis. Since 2010, we have worked with the U.S. Geological Survey’s Earth Resources Observation and Science (EROS) Center, the federal organization which maintains the Landsat long-term archive, to order, download, and add over 7M Landsat images to the Earth Engine public data catalog, which we make freely available online in an analysis-ready format in Earth Engine and on Google Cloud.
Scientists, researchers, and journalists using Earth Engine rely on our data catalog of over 200 open remote sensing datasets, including Landsat, as they pioneer new approaches in flood risk mapping, agriculture, Malaria and other infectious disease prevention, forest monitoring, land use change, and mapping global surface water occurrence in greater detail than ever before possible. Last year, journalists at the Center for Investigative Reporting used Landsat 8 imagery and Earth Engine for their Wet Prince of Bel Air investigation into residential water usage during the ongoing California drought.
Over the years, we’ve used the Landsat imagery to develop an incredibly accurate depiction of Earth and its changes over time, which we’ve published in Google Earth and Maps for use by billions of people worldwide.
Thanks to Landsat, we were able to dramatically improve our satellite base map in Google Earth and Google Maps on two separate occasions, first in 2013, and again in June 2016. Our most recent 15 meter-per-pixel global mosaic was made from over 1.5 million Landsat 7 and Landsat 8 images and forms the view of Earth you see across our mapping products for the first twelve zoom levels of the imagery basemap. To make the mosaic we looked at millions of images, threw out all the cloudy pixels, and took the clearest pixels to stitch together our cloud-free and seamless image.
More recently, we combined the Landsat archive with Sentinel-2 data to create a new version of our Earth Timelapse, a global, zoomable video that lets you see how the Earth has changed since 1984. Thanks to the Landsat Global Archive Consolidation (LGAC) program, we had access to nearly a million additional images acquired over Landsat’s 45-year lifespan, allowing us to produce a superior Timelapse with fewer artifacts like clouds.
From all of us here, we wish you a very Happy Birthday, Landsat!