Satellites: Make Earth observations open access : Nature News & Comment

"... A new era of open-access satellite data has arrived. In 2008, the US Geological Survey (USGS) released for free to the public its Landsat archive, which dates back to the 1970s and is the world's largest collection of Earth imagery2. Greater computing power is also enabling scientists to manipulate big data representing larger areas and with greater sophistication, to produce multibillion-pixel composite maps of land cover and change across regions, continents and the globe. Monitoring land-cover change in near-real time is now a reality. Obstacles remain. Data coverage in the Landsat archive is variable, in both space and time (see 'Global coverage'). And few people have enough computing power and bandwidth to download and manipulate the data. Decision-makers remain largely unaware of the vastly improved opportunities for environmental monitoring offered by the latest methods, and so are not yet using such data to their full potential. Scientists and policy-makers can support the shift to open-access satellite data, and coordinate efforts to deliver the detailed global monitoring required by international climate change and emissions-reduction programmes. Further, governments should open up their national satellite image archives and integrate compatible data to fill gaps. And satellite imagery from future missions should be freely accessible to all to promote innovation and use ... Governments and the remote-sensing community should now seize the opportunity to develop a unified strategy for land monitoring ... First, as much historical imagery as possible should be deposited in the Landsat archive or an equivalent open repository. Leading Earth-observation nations7 whose satellites have sensors that complement Landsat should explore opportunities to add their data to the global pool. Second, the Earth-observing community and governments should commit to making future satellite programmes open access whenever possible. We urge the European Space Agency to consider ways to widen access to Sentinel-2's images. Alternative delivery mechanisms, such as a third-party archive and distribution site, could make data available to a broader array of users, allowing the intended science benefits to be reached ... The remote-sensing community must advocate the development and maintenance of data archives and innovative processing methods. Best-practice approaches and standards can be developed by the Group on Earth Observations, a voluntary partnership between governments and international organizations to promote global collaboration around Earth observations, and offshoots such as the Global Forest Observation Initiative. To facilitate the use of data from differing sensors, scientists and data distribution centres should offer users calibrated data in widely compatible, analysis-ready formats ..."