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Question:

How accurate is the radiometric calibration of Landsat images?

Answer:

The ETM+ instrument aboard Landsat 7 was designed to maintain a radiometric accuracy of +/- 5% during its 5-year mission. The design supports this requirement through hardware design changes, prelaunch characterization, an on-orbit monitoring and calibration program, and changes in the ground processing of the data. Calibration Parameter Files (CPFs) describe radiometric and geometric data characteristics.