Accessing satellite data

Data acquisition with instruments mounted on airborne vehicles is commonly called remote sensing. Mounting sensors on satellites is a common practice by space agencies (for example, NASA and ESA), and other resourceful companies. These are also the main source of open source data as both NASA and ESA grant free access to preprocessed data coming from these sensors. In this part of the book, we will download remote sensing data (often called imagery) from USGS's portal: Earth Explorer. It can be found at  https://earthexplorer.usgs.gov/. As the first step, we have to register an account in order to download data.

When we have an account, we should proceed to the Earth Explorer application and select our study area. We can select an area on the map by holding down the Shift button and drawing a rectangle with the mouse, as shown in the following screenshot: