Satellites: make data freely accessible

Abstract

The cost of accessing satellite data is hampering the widespread application of satellite monitoring, a vital tool for controlling deforestation (Jim Lynch et al. Nature 496, 293–294; 2013). We urge government agencies producing taxpayer funded satellite images to make them available for free and in user-friendly formats. Lynch and colleagues call for daily satellite observations of forests, but that would mean aggregating information from numerous satellites that are operated by many countries. This aggregation is also seriously limited by a lack of policy among national governments to make satellite images freely accessible. Assembling the large data sets needed for global monitoring is therefore prohibitively expensive. One solution would be to combine data from the US Landsat satellites with those from the European Space Agency’s planned Sentinel-2 satellites — this could deliver optical imagery with global coverage every 3–5 days. The distribution of Landsat imagery has increased by two orders of magnitude since 2008, when the US Geological Survey made all the data free to access online. Data from NASA’s MODIS and all of their Earth-observation imagery are also available for free, as are data from the China–Brazil Earth Resources Satellite programme.