GIS

The USGS collects a huge amount of satellite imagery for mapping uses. You can search by address, feature, or coordinates, and the data is filterable by date. Check out the “Data Sets” tab to see all the sources you can pull from including Aerial Imagery, Commercial Satellites, Landsat, and Radar. These maps are excellent for evaluating vegetation, changes in sea level, etc. Remember that though these datasets do their best to select the clearest imagery, it’s always a good idea to download a few days in a row to ensure you don’t get an image with too much cloud coverage. This is USGS, but most datasets are global, so don’t hesitate to check even for non-US data.

Copernicus is an EU program designed to develop Europe’s scientific information with satellite imagery of Earth, but they provide free open access to all users. You can draw a box or a polygon around your area of interest, and apply filters to drill down to more specific information. These filters are highly specific, so it helps significantly to know exactly what you’re looking for. Browsing isn’t the easiest prospect here! You can sort by satellite platform, sensing or ingestion period, cloud cover, or Sentinel mission (these are Europe’s satellite launches from their space program).

This is yet another reliable source for satellite data. Most of their datasets are available in daily TAR files for the last 90 days. There are nine data products, and sets are searchable by name under the “Search for Data” tab. In my opinion, the best is the Environmental Data from Polar-orbiting Satellites set. As with all these satellite imagery sources, it’s best to look carefully to find the one that suits your needs for quality, location, age, etc.

EarthDATA is run by the masters of satellite data, NASA! There is fantastic filtering available here, and data is available in near real time. Check out “Keywords” to get a quick overview of the topical scope available. As you might expect, biosphere, land surface, and atmosphere are the most numerous. I highly recommend you take the tour the site offers when you first visit. It’s a handy guide to utilizing all the features on EarthDATA. NASA has over 6,000 collections hosted here, so you’re bound to find imagery for almost every purpose.