Check out these resources for free raster and geospatial data.
(The Green Swamp with false color and radiometric enhancements in SNAP)
1. EARTHEXPLORER and GloVis This is the USGS arm for raster data. There are twenty different satellite collection sources to choose from. You can use a shapefile or KML file to designate the coverage area you want or zoom in to the visible are on the map. EarthExplorer is the new and improved version of GloVis.
2. Copernicus Access to a global network of thousands of land, air, and marine-based sensors covering Europe and other select areas.
3. OpenStreetMap OpenStreetMap is a community mapping project that allows you to work with and edit various vector map layers (transportation, cycling, humanitarian) and download them.
4. NASA NEO and SEDAC - Get Earth observation imagery from NASA and select from several different data sets: vegetation, sea surface temperature, solar insolation, land surface temperature anomaly and many more. SEDAC is the NASA site for Socioeconomic Data and Applications Center. Here you can use their map viewer to see visualized socioeconomic, environmental and remote sensing imagery.
5. Open Topography - This is a wonderful site for high resolution topography point cloud and raster data.
6. UNEP United Nations and FAO GeoNetwork - Via UNEP you can access data from the Biodiversity Lab and many other branches and browse by topic. FAO is the UN agency for agriculture, forestry, fisheries and rural development. You'll find all kinds of data here, including historical maps.
7. Geofabrik - This is a consulting firm in Germany that offers OSM featureless data for download, as well as a plethora of contracted geospatial services should you need them.
8. North Carolina Spatial Data Download - If you need some North Carolina raster data, look no further. This is a great site for DEMs and LiDAR, Floodplain Hazards and the built environment. The LiDAR data is 1 meter pixel with 2 points per meter, or 8 points per meter in western counties..