What is the difference between the CPF Effective date and Version date?

Question:

Answer:

Calibration Parameter Files (CPFs) each have an Effective date and a Version date. The Effective date of the CPF must match the acquisition date of the scene. A CPF version is active until it is superseded by a new CPF for that date period. Data can be processed with any version of a CPF; the later versions have more refined parameters.

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Landsat represents the world's longest continuously acquired collection of space-based moderate-resolution land remote sensing data. Four decades of imagery provides a unique resource for those who work in agriculture, geology, forestry, regional planning, education, mapping, and global change research. Landsat images are also invaluable for emergency response and disaster relief.