Here at Apollo Mapping, we want you to find the satellite imagery you need, even if that means finding free imagery using tools besides Image Hunter. In this Free For All edition, we will review several sources of free imagery, and while each download system is different, you must expect the data to be limited in various ways.
In some cases, experience with GIS is a determining factor in finding satellite imagery. To access the oldest and widest ranging catalog of imagery, the United States Geological Survey (USGS) created an online tool known as Earth Explorer. Not only must you sign up for an account to download imagery, it also requires knowledge of GIS platforms and geospatial data to use efficiently. To begin, there is a plethora of data to sort through, ranging from optical imagery to aerial, UAV, radar and digital elevation models (DEMs). To search, users can enter coordinates, addresses or geographic features, draw their own region of interest, or upload a KMZ/KML/shapefile. Results can be filtered by area, date, cloud cover and specific sensors. Earth Explorer now includes even more medium-resolution imagery as the Sentinel-2 archive from the European Space Agency (ESA) was added recently. Sentinel-2 data can also be accessed via the Copernicus Open Access Hub, which is a relatively straightforward webmap that filters and downloads imagery from any of the three Sentinel missions.
An additional platform I would recommend is NASA’s Earthdata Search. Earthdata Search is a great place to find… you got it, data about the Earth! Much of it comes from analyses done in Earth science projects by NASA, hailing from the Earth Observing System Data and Information System (EOSDIS) Distributed Active Archive Centers (DAACs). There is a plethora of land use and land cover data that is specifically satellite-derived, such as permafrost and forest types. Users can filter searches in a variety of ways, including by features, keywords, platforms, instruments, organizations and more. But, in order to view or save the data, you need to create an account.
If you are interested in checking out more near real-time satellite imagery or completely free-to-use software that contains imagery, try Google Earth or Bing Maps as well as this tool from NOAA and NASA’s Worldview.
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