Earth Observation Open Data Imagery
Earth observation imagery is a valuable resource for researchers, environmentalists, governments, and businesses alike. By providing data on a variety of global parameters, these images help us understand our planet and make informed decisions.
This article explores the available sources of earth observation open data (i.e. free) imagery, the data they provide, licensing terms, URLs for accessing the imagery, and user reviews to help you decide which source is right for your needs.
NASA Worldview
Data available: NASA Worldview provides satellite imagery from multiple sources, including the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua satellites, the Visible Infrared Imaging Radiometer Suite (VIIRS), and the Global Precipitation Measurement (GPM) mission, among others.
Licensing terms: NASA’s satellite imagery is available under the public domain, meaning it can be used for any purpose without restrictions.
URL: https://worldview.earthdata.nasa.gov/
USGS EarthExplorer
Data available: The United States Geological Survey (USGS) EarthExplorer offers a vast collection of satellite imagery, aerial photographs, and other remote sensing data. This includes Landsat, Sentinel-2, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and more.
Licensing terms: Most of the data provided by USGS is available under the public domain, but some datasets might have additional restrictions. Users are advised to check the specific licensing terms of the data they intend to use.
URL: https://earthexplorer.usgs.gov/
Copernicus Open Access Hub
Data available: The Copernicus Open Access Hub offers free access to satellite imagery from the European Space Agency’s Sentinel missions. This includes data from Sentinel-1 (radar imagery), Sentinel-2 (optical imagery), and Sentinel-3 (specialized Earth observation sensors).
Licensing terms: Copernicus data is available under the Copernicus free and open data policy, which allows users to access, use, and redistribute the data without restrictions.
URL: https://scihub.copernicus.eu/
Google Earth Engine
Data available: Google Earth Engine provides access to a vast repository of satellite imagery and geospatial data, including Landsat, Sentinel-2, MODIS, and more.
Licensing terms: Data accessed through Google Earth Engine is subject to the licensing terms of the respective data providers. Most datasets are available under open data policies; however, users should verify the specific licensing terms for each dataset.
URL: https://earthengine.google.com/
User Reviews
NASA Worldview: Users praise the easy-to-use interface and high-quality imagery provided by NASA Worldview. The public domain licensing makes it a popular choice for many applications, including research and education.
USGS EarthExplorer: EarthExplorer is known for its extensive collection of datasets and the ability to filter search results based on parameters like date, cloud cover, and sensor type. Users appreciate the advanced search capabilities but note that the interface can be overwhelming for beginners.
Copernicus Open Access Hub: The Copernicus Open Access Hub is lauded for its free access to high-quality Sentinel imagery. Users appreciate the frequent updates (Sentinel-2 imagery is available every 5 days) and the wide range of applications supported by the data.
Google Earth Engine: Google Earth Engine stands out for its powerful analytical capabilities, enabling users to perform advanced geospatial analysis on the platform. The extensive dataset collection and integration with other Google products make it a popular choice among researchers and developers. However, some users find the learning curve to be steep, especially for those unfamiliar with coding.