There are now vast collections of remote sensing imagery available, much of it readily available for you to download, but it’s not always obvious where and how to access these archives. Below we explore some of the many publically available resources where users can search for and download remote sensing data for their own projects.
As you would expect, government agencies support some of the largest remote sensing data resources, most notably NASA in the U.S. and the ESA in Europe. These agencies provide robust web-clients that can be easily used to discover and download extensive collections of Earth observing data:
- For NASA, the centralized go-to data repository can be found on the Earthdata website, which itself provides an integrated portal for accessing a wealth of information related to NASA’s Earth Observing System Data and Information System (EOSDIS). Within the Earthdata website you will find links to Reverb, the “Next Generation Earth Science Discovery Tool”, which allows users to search and explore more than 3200 different datasets distributed throughout NASA’s 12 EOSDIS Data Centers.
- For the ESA, which represents an international consortium of more than 20 European Member States, Earth observing data is primarily hosted through Earthnet Online. This website offers users access to data from the full collection of different ESA Earth Observing Missions, Third Party Missions, ESA Campaigns, and GMES Space Component data.
For other entry points to U.S. data archives, you can also visit the USGS Global Visualization Viewer (GloVis) or USGS EarthExplorer (EarthExplorer) to access data from particular sets of sensors. Alternatively, one can directly visit the various EOSDIS Data Centers, which each provide their own unique data discovery tools, such as the NSDIC Data Search tool at the National Snow & Ice Data Center (NSDIC) Distributed Active Archive Center (DAAC) and the Mercury tool at the Oak Ridge National Laboratory (ORNL) DAAC for Biogeochemical Dynamics. For projects with time dependency constraints, such as natural disaster monitoring, there is also the option to download near real-time data from certain sensors using the Land Atmosphere Near Real-Time Capability for EOS (LANCE) tool. And for data from NOAA’s archives, the Office of Satellite and Product Operations (OSPO) provides links to a number of different data discovery tools, including NOAA’s Comprehensive Large Array-Data Stewardship System (CLASS). In the end, there is usually more than one way to reach the same data; it’s really a question of what tools you find easiest to use and which are most relevant to your intended application.
Searchable archives are also similarly available amongst various space agencies in other countries. For example, the Japan Aerospace Exploration Agency (JAXA) hosts the Earth Observation Research Center (EORC) Data Distribution Service (DDC), and the Indian Space Research Organisation (ISRO) offers Bhuvan, the geoportal for the National Remote Sensing Centre (NRSC) Open EO Data Archive (NOEDA).
And there are also commercial archives, such as the DigitalGlobe ImageFinder, which include high resolution satellite and aerial imagery from around the globe. While images from these archives do have a price tag, given the high spatial resolution and global coverage, such imagery can be an excellent resource for many different applications.
The above compilation is but a subset of what is ultimately available for users to access. The full extent of imagery that can be obtained, particularly when considering the many secondary data resources available from individual entities and researchers, is truly astounding. Additionally, as more and more Earth observing satellites are launched, and as airborne imagery becomes more cost efficient and easier to collect, the scope and number of both government and commercial archives will continue to expand.
What will remain a challenge is for these archives to maintain robust data discovery tools that can be used access the growing volume of data, that can adapt to new sensors and new image formats, and that can integrate data across different archives. As evident above, great progress has been made in this domain, and developers continue to explore and implement new tools for managing this valuable global resource.
So get out there and put these data discovery tools to work for your project.