Landsat helped turn Earth observation from analogue photography into a quantitative science. A digital sensor records energy in several bands, and an algorithm helps convert those measurements into useful information. The resolution of the sensor limits the size of the features that a map can show.
Calibration helps measurements remain consistent so researchers can compare places and changes over time. Interpretation still has uncertainty because every product has a stated scale and purpose. A precise-looking map can be reliable without being perfect. Readers should check the sensor, processing method, resolution and calibration before making a detailed claim. A satellite product is measured, processed and calibrated evidence. This important distinction prevents the sharp appearance of a digital product from being mistaken for unlimited scientific certainty. It applies across products.